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General Discussion => General Discussion => Topic started by: mr. mark on 02/15/2013 05:14 AM

Title: Meteor Strikes Chelyabinsk, Russia
Post by: mr. mark on 02/15/2013 05:14 AM
A meteor has struck Chelyabinsk inside Russia. Air defenses have hit the meteor.
http://rt.com/news/meteorite-crash-urals-chelyabinsk-283/

https://www.youtube.com/watch?v=QIMKQihoYRI&feature=player_embedded
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: catdlr on 02/15/2013 05:52 AM
Here is another from a closer vantage point:

Meteor Hits Russia Giant Meteor shower Over Russia

Published on Feb 14, 2013
Giant Meteor Explodes Over Russia meteorite may be part of Giant Asteroid that nearly Collided with earth Meteor shower reported in eastern Russia


https://www.youtube.com/watch?v=BO_uo0bPbu4


Quote
A powerful blast rocked the Russian region of the Urals early on Friday with bright objects, identified as possible meteorites, falling from the sky, emergency officials said.

"It was definitely not a plane," an emergency official told Reuters, without elaborating. "We are gathering the bits of information and have no data on the casualties so far."

No one was hurt in a meteor shower, an emergency official told RIA-Novosti. Local residents said they witnessed burning objects in the sky of the Chelyabinsk and Sverdlovsk regions.

A Reuters witness in Chelyabinsk reported hearing a huge blast early in the morning and feeling a shockwave in a 19-storey building in the town center.

The sounds of car alarms and breaking windows could be heard in the area, the witness said, and mobile phones were working intermittently.


"Preliminary indications are that it was a meteorite rain," an emergency official told RIA-Novosti. "We have information about a blast at 10,000-meter (32,800-foot) altitude. It is being verified."

The trace from a falling object could be seen in Yekaterinburg, some 200 kilometers (125 miles) southeast of Chelyabinsk, another Reuters witness said.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Bubbinski on 02/15/2013 06:43 AM
Lots of crazy, amazing videos out there.  Apparently an airburst or strike on Chelyabinsk, reports of a zinc factory being damaged and over 100 injured.  Some on Twitter are saying it would have come from the wrong direction for a companion object of DA14.

As far as air defenses shooting it down, I'm not sure how that would even be possible.  Maybe a Russian equivalent of that Air Force 747 with the laser in the nose?  But I'm not sure shooting at it just to break it up into more pieces that hit the ground would be advisable.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mlindner on 02/15/2013 06:52 AM
Lots of good videos here. Huge explosions, reports of many people injured from falling glass and shockwaves. Meteor boloid was brighter than the sun.

http://www.slate.com/blogs/bad_astronomy/2013/02/15/breaking_huge_meteor_explodes_over_russia.html
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mlindner on 02/15/2013 06:55 AM
Lots of crazy, amazing videos out there.  Apparently an airburst or strike on Chelyabinsk, reports of a zinc factory being damaged and over 100 injured.  Some on Twitter are saying it would have come from the wrong direction for a companion object of DA14.

As far as air defenses shooting it down, I'm not sure how that would even be possible.  Maybe a Russian equivalent of that Air Force 747 with the laser in the nose?  But I'm not sure shooting at it just to break it up into more pieces that hit the ground would be advisable.

No its most certainly a meteorite. Probably not related to DA14. Different direction of travel (from looking at videos). It's also many hours in advance which puts it in a different orbit.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Maciej Olesinski on 02/15/2013 07:51 AM
I hope this will make humanity working harder in space technologies.

Few links:
Inside:
https://www.youtube.com/watch?v=1kvHl5Qcnzc

Explosion:
http://www.youtube.com/watch?v=b0cRHsApzt8

And another:
http://www.youtube.com/watch?v=inPclE7RwFY
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Star One on 02/15/2013 07:54 AM
I know this is not strictly spaceflight related but it does demonstrate why we need a good early warning system for these object be it on the ground or in space.

 http://www.guardian.co.uk/science/2013/feb/15/meteorite-explosion-shakes-russian
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Star One on 02/15/2013 08:04 AM
There's a thread over in space Science, but I think it might be prudent to merge or move that thread to general or live event, because this could be an event. Especially if they find fragments or the like.

What with the asteroid close encounter tonight and taking a positive from this event, it must be doing a lot for pushing this whole issue up the agenda & maybe as a result some will follow the attention for getting things moving on the early warning front.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Damon Hill on 02/15/2013 08:15 AM
Quite a contrail, too.  Must have been a lot of water and other volatiles, perhaps a small comet?

Tunguska, anyone?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Dalhousie on 02/15/2013 08:45 AM
http://www.bbc.co.uk/news/world-europe-21468116

At least 400 injuries.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: DLR on 02/15/2013 08:51 AM
I wonder whether it's connected to the Pope's abdication? :P


In all seriousness, itt shows what kind of energy even a small object will release upon impact. Hope this event lead to further efforts by space agencies to get more serious about asteroid identification and deflection. Deputy Prime Minister Rogozin already mentioned that Russia will look into that further.

Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Targeteer on 02/15/2013 09:00 AM
Visible from space.  From ESA via Facebook...

http://www.flickr.com/photos/simon_rp/8474794165/
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Satori on 02/15/2013 09:02 AM
The images and videos of this event are amazing. Check at http://zyalt.livejournal.com/722930.html#cutid1
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Maciej Olesinski on 02/15/2013 09:05 AM
http://say26.com/meteorite-in-russia-all-videos-in-one-place

all videos in one place
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: shuttlelegs on 02/15/2013 09:18 AM
WOW
that was a close one.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Kaputnik on 02/15/2013 09:31 AM
Any ideas about what sort of size this was? Smaller than Tunguska?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 02/15/2013 09:36 AM
Has to be much smaller than Tunguska. Thousands if not hundreds of thousands of people would be dead if this were Tunguska.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Star One on 02/15/2013 09:46 AM
Any ideas about what sort of size this was? Smaller than Tunguska?

Have seen one to two metres mentioned.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Dalhousie on 02/15/2013 09:55 AM
All the reports, videos, etc. are from 200-300 km away, nothing from near the imapct site.  At least 500 (mostly minor) injuries so far, but from 250 90 minutes ago.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: smoliarm on 02/15/2013 09:59 AM
Any ideas about what sort of size this was? Smaller than Tunguska?

MUCH smaller, fortunately. At Tunguska site, there was area of ~10 km2 with forest burned to ashes.

Interesting detail on trajectory calculations: there is report on ONE MORE similar event (although less violent) some 500 km North-East from Chelyabinsk. It happened almost at the same time, near Tavda village of Tumen' region:
http://www.gazeta.ru/social/news/2013/02/15/n_2756425.shtml
- The locals reported loud rumbling noise, rattling windows, smoke trail.


>>Any ideas about what sort of size this was?
The energy release depends on velocity and angle more than on the size. Without such info, it could be anywhere from kilograms to hundreds of kilograms.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Dalhousie on 02/15/2013 10:13 AM
The video show it moving ESE to WNW, does this tell us something immediately about the type of orbit?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Ben the Space Brit on 02/15/2013 10:21 AM
This probably is unrelated to 2012 DA14.  The biggest thread of evidence is that the two major objects in the 15/2/13 shower were in the north-east whilst 2012 DA14 is approaching from the south-west.

The only way to wiggle around it would be to suggest that Earth 'overtook' a cloud of far smaller objects in a parallel orbit to 2012 DA14.  This would account for the direction of approach and the relatively low contact velocity.  However, I don't personally expect this theory to turn out to be even close to the truth.

Either way, 500 people were injured today by an object that dropped out of a clear blue sky with little or no warning.  The airburst was pretty fierce and I suspect that only luck meant that no-one was killed by falling structural debris from the concussion wave blowing out windows and removing poorly-secured roofs.

I call 'bovine excrement' on the claim that the object was disintegrated by a Russian SAM - a conventional air intercept missile wouldn't even scratch an impactor of that size, even assuming it was able to get close enough.  That statement was almost certainly released in an attempt to calm panic, combined with possibly an ambitious junior officer trying to earn praise for his quick thinking and heroic resolution in the face of an unexpected crisis.  FWIW, I can't believe that, from first contact to detonation, there would have been sufficient time to bring an SAM system on-line, launch a missile and for it to reach IP with the object.  This is ignoring the amount of time it would have taken to navigate Russia's traditionally labyrinthine military and civil bureaucracy to ger permission to engage the intruder object.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 02/15/2013 10:23 AM
If you listened to the videos, though, you can hear what sound like air defense weapons.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mmeijeri on 02/15/2013 10:26 AM
If you listened to the videos, though, you can hear what sound like air defense weapons.

Weren't those just sonic booms from several meteoroid fragments?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: R7 on 02/15/2013 10:35 AM
If you listened to the videos, though, you can hear what sound like air defense weapons.

Weren't those just sonic booms from several meteoroid fragments?

Might also be sounds of disintegrating fragments going through final explosions. IIRC at some point a comet fragment can no longer stand the atmospheric heating and sort of flash evaporates.

edit:
Quote
Any ideas about what sort of size this was? Smaller than Tunguska?

Local news quoted Itar-Tass as source and said the russian science academy thinks object was several meters in size, about ten tons in weight and had [explosive?] force of several kilotons. Entered atmosphere with 15-20km/s velocity,  disintegrated at 30-50km altitude.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: smoliarm on 02/15/2013 10:49 AM
If you listened to the videos, though, you can hear what sound like air defense weapons.

Weren't those just sonic booms from several meteoroid fragments?

Exactly. This is not the first time such event got on record, although by the abundance of recordings from different angles this one is the best.

On the size estimate:
this video
http://www.youtube.com/watch?feature=player_embedded&v=4ZxXYscmgRg#!
shows the whole process, it took ~ 12 seconds from the first trail to the explosion implying moderate velocity. This places size estimate in hundreds-of-kg range.

The progress of events and the trail appearance are quite typical for meteorite fall.
BTW, the sonic boom and shock wave are due to huge kinetic energy release, and high volatile content is not necessary. Most likely, this was stony meteorite with very low volatile content.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Dalhousie on 02/15/2013 10:52 AM
Eye witness report on the BBC site:

"there was a huge explosion, followed by lots of little explosions", typical of a bolide break-up, albeit a very big one.  Reports of ijuries seem to have stablished at just over 500, with 11 hospitalisations.  Still nothing on the impact site or about any recovery of material.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Dalhousie on 02/15/2013 10:57 AM
Tass is now saying that about one hundred people have been hospitalised and meteorite fragments have been recovered in three places, two in the Chebarkul district and one the Zlatoust district of the of the Chelyabinsk region.

I imagine most injuries would be due to flying glass or people being knocked over from the shockwave.

Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mmeijeri on 02/15/2013 11:03 AM
Most likely, this was stony meteorite with very low volatile content.

So the trail would be made up of something like very fine ash, not water vapour? That suggests it would fall to the ground and could be examined.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: smoliarm on 02/15/2013 11:05 AM
... Still nothing on the impact site or about any recovery of material.

"Military found impact site "
http://lenta.ru/news/2013/02/15/found/

(http://cdn.lenta.ru/images/0000/0298/000002981473/pic_1360928973.jpg)

They report a 6-meter hole in the thick ice on the lake Chebarkul, 50 km West from Chelyabinsk.

Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: aquanaut99 on 02/15/2013 11:07 AM

>>Any ideas about what sort of size this was?
The energy release depends on velocity and angle more than on the size. Without such info, it could be anywhere from kilograms to hundreds of kilograms.

Looking at the videos, the main airburst flash event (the one that lit everything up) lasted around 1 to 2 seconds. With a nuke, that would indicate a yield of about 10 kilotons. Now I know a meteor is not a nuke, but the energy release is similar, tho more spread out. I'd say this was a Hiroshima that detonated at 10km altitude, which could cause some windows on the ground to burst.

Incidentally, I agree that the air-defence story is BS. The meteor blew up at 10 km altitude, with some fragments reaching the ground afterwards. There is no way a SAM could have reached that altitude in time, if launched when the object first lit up. Also, it wouldn't have had much effect on a block of rock and ice even if it did.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: R7 on 02/15/2013 11:07 AM
Found the original itar-tass article about size

http://www.itar-tass.com/en/c507/651171.html (http://www.itar-tass.com/en/c507/651171.html)

edit: if there were SAM activity there would have been contrails, no?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Ben the Space Brit on 02/15/2013 11:09 AM
People tend to sneer at 'what if...?' scenarios but I think we'd be talking about the first confirmed direct mass fatalities from a cosmic collision this morning if it weren't for the fact this shower was over a sparsely-inhabited area.  Stick the same event over a heavily-occupied region in Western Europe and it would have been a very different story.

@smoliarm

The final flare-out was extremely bright but not atypical of similar bolides I've seen in videos from the northern US and Canada.  Are you sure it was volatile-low? I would have thought that there would have to be some kind of volatile content to act as 'fuel' for the final detonation, although I'm sure there's a silicate or metallic core around which the object formed.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: aquanaut99 on 02/15/2013 11:10 AM
Found the original itar-tass article about size

http://www.itar-tass.com/en/c507/651171.html (http://www.itar-tass.com/en/c507/651171.html)

Hey, thanks! Looks like my yield guess was pretty close...  :D
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mmeijeri on 02/15/2013 11:13 AM
People tend to sneer at 'what if...?' scenarios but I think we'd be talking about the first confirmed direct mass fatalities from a cosmic collision this morning if it weren't for the fact this shower was over a sparsely-inhabited area.

True, but much of the Earth's surface is covered in water and much of the land mass is sparsely populated, so most hits are going to be like that. Still, it would take only one unlucky hit to do massive damage.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: R7 on 02/15/2013 11:24 AM
although I'm sure there's a silicate or metallic core around which the object formed.

In this particular video you can see narrow streak and smaller bright blob shooting out the big contrail after main flash, might that be the denser core? Attached capture, blob at the very right edge.

edit: Btw majestic lightshow on the sky, atomic bomb level bright flash, and what does the driver do? Nothing, keeps overspeeding and listening to cheesy pop like nothing happened. At least adjust the dashboard cam clock! ::)

http://www.youtube.com/watch?feature=player_embedded&v=4ZxXYscmgRg (http://www.youtube.com/watch?feature=player_embedded&v=4ZxXYscmgRg)



Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: tigerade on 02/15/2013 11:27 AM
Wow, scary!  What a crazy thing to wake up to.

Seeing these videos of a small meteor causing havoc makes me really want to avoid a big meteor.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: smoliarm on 02/15/2013 11:32 AM
Found the original itar-tass article about size

http://www.itar-tass.com/en/c507/651171.html (http://www.itar-tass.com/en/c507/651171.html)

edit: if there were SAM activity there would have been contrails, no?

I saw it, I'd treat it as a max estimate. As we know now the impact site, the altitude of explosion reported by itar-tass  looks way too high. My guesstimate - it was lower-altitude, lower size explosion.

>>if there were SAM activity there would have been contrails, no?
exactly.
From how it looks on all recordings - it was natural meteorite fall with no human interference :)
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Star One on 02/15/2013 11:47 AM
... Still nothing on the impact site or about any recovery of material.

"Military found impact site "
http://lenta.ru/news/2013/02/15/found/

They report a 6-meter hole in the thick ice on the lake Chebarkul, 50 km West from Chelyabinsk.



I assume they will be aiming to recover what's left from down there, or is the lake too deep for recovery?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: douglas100 on 02/15/2013 11:49 AM

Are you sure it was volatile-low? I would have thought that there would have to be some kind of volatile content to act as 'fuel' for the final detonation, although I'm sure there's a silicate or metallic core around which the object formed.

I don't think so. The very rapid conversion of kinetic energy into heat is enough to make it detonate (a slightly slower version of the detonation which occurs when a solid body strikes a planetary surface at 10+ kilometres a second.) That doesn't mean there weren't volatiles in the object, of course.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: smoliarm on 02/15/2013 11:53 AM
Most likely, this was stony meteorite with very low volatile content.

So the trail would be made up of something like very fine ash, not water vapour? That suggests it would fall to the ground and could be examined.

Yes, and that's what my friends from Russian Meteorite Сommittee are doing now :)

About the trail - its major components are FeO, SiO2 and SO2 in amorphous form (therefore it is colorless). Major chemical reactions at the trail formation: BEFORE the bright light -- decomposition of meteoritic troilite (FeS) and its oxidation; AT the light -- evaporation and oxidation of kamasite (Fe-Ni alloy). All these are energy-releasing, but they add almost nothing to the BOOM :)
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: smoliarm on 02/15/2013 12:29 PM
...  Are you sure it was volatile-low?

No, I'm not, but it's a safe guess, based on 2 points:
= the appearance is quite similar to known falls of stone meteorites
= for violent shock wave high volatile content is not necessary, kinetic energy of 15-20 km/sec is quite enough.

Anyway, if they find another impact site (there should be dozens), not on the lake ice, but on the ground - we will know pretty soon what it was.

>>People tend to sneer at 'what if...?'
Well, this is so far the worst meteorite event in the recorded history:
= That's the very first time with injuries and substantial property damage
= The last time meteorite explosion shattered windows was in 18th century

For more statistics one can check Meteorite Catalog by Monica Grady, I do not have it right now.

The bottom line - meteorites are not that dangerous :)
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: smoliarm on 02/15/2013 12:52 PM
although I'm sure there's a silicate or metallic core around which the object formed.

In this particular video you can see narrow streak and smaller bright blob shooting out the big contrail after main flash, might that be the denser core? Attached capture, blob at the very right edge.

edit: Btw majestic lightshow on the sky, atomic bomb level bright flash, and what does the driver do? Nothing, keeps overspeeding and listening to cheesy pop like nothing happened. At least adjust the dashboard cam clock! ::)

http://www.youtube.com/watch?feature=player_embedded&v=4ZxXYscmgRg (http://www.youtube.com/watch?feature=player_embedded&v=4ZxXYscmgRg)





>>might that be the denser core?
Almost certainly, no. From planetology view, it was a small fragment, about a meter or so.
1. Core-shell structure forms only on a large bodies (kilometers, or, more likely - hundreds of km).
Smaller asteroids do not possess gravitational "strength" to develop such structure.
2. Meter-size fragment does not have the ability even to grow ices on its surface.

The narrow streak you noted likely represents just the biggest piece after main explosion.


Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Artyom. on 02/15/2013 01:00 PM
It is possible fragments of the meteorite :-\ .

http://74.mvd.ru/news/item/845855/
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Chris Bergin on 02/15/2013 01:16 PM
Pretty amazing stuff, especially the videos from cameras on car dashboards.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Ben the Space Brit on 02/15/2013 01:18 PM
Pretty amazing stuff, especially the videos from cameras on car dashboards.

You get regular videos on Youtube of similar events from North America at a rate of 1-2 per year.  However, this object does seem to have been unusually large.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: kevin-rf on 02/15/2013 01:37 PM
I wonder if our Russian readers can fill us in, but youtube is filled with tons of russian dash cam video's of drivers doing everything and anything. Does every Russian drive with a dash cam running?

I've seen at least a dozen separate dash cam video's of this event as it happened now.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Ben the Space Brit on 02/15/2013 01:38 PM
I wonder if our Russian readers can fill us in, but youtube is filled with tons of russian dash cam video's of drivers doing everything and anything. Does every Russian drive with a dash cam running?

I've seen at least a dozen separate dash cam video's of this event as it happened now.

There's a lot of insurance fraud in Russia.  Having dash cams to prove whether you actually hit that particular car or person is a lot of help in the civil litigation court.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: cneth on 02/15/2013 01:41 PM
I wonder if our Russian readers can fill us in, but youtube is filled with tons of russian dash cam video's of drivers doing everything and anything. Does every Russian drive with a dash cam running?

I've seen at least a dozen separate dash cam video's of this event as it happened now.

I'm not russian, but you might read this article:

http://www.animalnewyork.com/2012/russian-dashcam/

Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Chris Bergin on 02/15/2013 01:48 PM
Video on Sky News (UK) shows CCTV from inside buildings, as they had windows blown out and doors blown off! :o

http://news.sky.com/story/1052514/meteorite-shower-hits-russia-injuring-over-900
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: rdale on 02/15/2013 01:48 PM
Also http://www.geek.com/articles/geek-pick/why-are-there-so-many-russian-dash-cam-videos-on-the-internet-2013019/
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Gene DiGennaro on 02/15/2013 01:50 PM
Glad this didn't happen during the height of the Cold War.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Ben the Space Brit on 02/15/2013 01:51 PM
Video on Sky News (UK) shows CCTV from inside buildings, as they had windows blown out and doors blown off! :o

http://news.sky.com/story/1052514/meteorite-shower-hits-russia-injuring-over-900

Even at 10,000m, the blast pressure wave was in the high-explosive bomb  level of force.

The damage to the zinc factory was quite impressive; I hope no-one was buried under any of that!
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Chris Bergin on 02/15/2013 01:56 PM
Here's the location:

(http://media.skynews.com/media/images/generated/2013/2/15/221496/default/v1/map-1-522x293.jpg)
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Ben the Space Brit on 02/15/2013 02:03 PM
The vapour trail is interesting.  It clearly divides into two trails, one of which suddenly vanishes.  That would suggest that the object was breaking up into smaller segments as it descends.  Maybe the trail that vanishes is the object that explodes and the other trail is the object that broke apart at a lower altitude and struck the lake?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: ugordan on 02/15/2013 02:09 PM
Based on the shockwave damage alone, I would agree that this probably in the low kiloton range, up to 10 kT perhaps, although I'd put my WAG at slightly less than that.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: JohnFornaro on 02/15/2013 02:13 PM
The Russians have all the fun... 1908 ... 2013 ... Nothing ever happens around here.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mlindner on 02/15/2013 02:16 PM
The meteorite didn't detonate. The explosion sounds are pieces of the meteorite going supersonic/hypersonic velocities with the largest piece having the loudest initial bang.

Edit: Large impact crater!
http://www.youtube.com/watch?v=_cd47Q44igI

Another shockwave video:
http://www.youtube.com/watch?v=0ozSq3yEm3g
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: kevin-rf on 02/15/2013 02:27 PM
No, it shattered. Hitting the lower atmosphere at those speeds is like hitting concrete. They are estimating a mass of about 10 tonnes, about a cubic meter in size.

Big things come in small packages ;)
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 02/15/2013 02:32 PM
The meteorite didn't detonate. The explosion sounds are pieces of the meteorite going supersonic/hypersonic velocities with the largest piece having the loudest initial bang.

Edit: Large impact crater!
http://www.youtube.com/watch?v=_cd47Q44igI

Another shockwave video:
http://www.youtube.com/watch?v=0ozSq3yEm3g
Your first video is of something completely different... Entirely terrestrial.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mlindner on 02/15/2013 02:32 PM
No, it shattered. Hitting the lower atmosphere at those speeds is like hitting concrete. They are estimating a mass of about 10 tonnes, about a cubic meter in size.

Big things come in small packages ;)

Right but shattering isn't detonating. It confuses people into thinking the shockwaves are from it exploding. I would say "it disintegrated."
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mlindner on 02/15/2013 02:33 PM
The meteorite didn't detonate. The explosion sounds are pieces of the meteorite going supersonic/hypersonic velocities with the largest piece having the loudest initial bang.

Edit: Large impact crater!

Another shockwave video:
Your first video is of something completely different... Entirely terrestrial.

If you're saying its volcanic, thats not like any volcanic thing I've seen before.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: rds100 on 02/15/2013 02:34 PM

 Large impact crater!


This is not the impact crater, someone is just joking.

edit: Here - http://en.wikipedia.org/wiki/Derweze
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mlindner on 02/15/2013 02:37 PM

 Large impact crater!


This is not the impact crater, someone is just joking.

edit: Here - http://en.wikipedia.org/wiki/Derweze


Bah darn it. I even saw a russian news station reporting as meteorite impact. Guess it fooled a bunch of people.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: JohnFornaro on 02/15/2013 02:38 PM
No, it shattered. Hitting the lower atmosphere at those speeds is like hitting concrete. They are estimating a mass of about 10 tonnes, about a cubic meter in size.

Big things come in small packages ;)

PRI's news release inflated that estimate:

Quote from: Lewicki
Hi there,

As you probably have heard, today, February 15th, a 150-foot (45 meter) asteroid is whizzing by the Earth a hair’s breath from the surface.  Missing us by only 14,000 miles, well within the 22,300 mile orbit of the Geostationary satellites that orbit around the Earth’s equator.  I wanted to put this in perspective for you with some of the chilling and fascinating facts:
This is approximately the same size as the asteroid that hit the Earth in Russia in Siberia (the “Tunguska Event”) on June 30th 1908.

That impact was equivalent to 1,000 Hiroshima nuclear bombs & knocked down 80 million trees down over an area covering 2,150 square kilometers (830 sq mi).

Had it hit near a population center it would have killed millions of people.

Today, there are approximately 610,000 asteroids that are actively tracked in our Solar System.  This number represents less than one percent of the more than 60 million asteroids that orbit the Sun.
 
To learn more about the threat that these asteroids pose and what Planetary Resources, Inc. and the Asteroid Mining industry can do to help protect the Earth, CLICK HERE.
 
-Chris Lewicki
President & Chief Asteroid Miner

Good for business.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mlindner on 02/15/2013 02:41 PM
No, it shattered. Hitting the lower atmosphere at those speeds is like hitting concrete. They are estimating a mass of about 10 tonnes, about a cubic meter in size.

Big things come in small packages ;)

PRI's news release inflated that estimate:

Quote from: Lewicki
Hi there,

As you probably have heard, today, February 15th, a 150-foot (45 meter) asteroid is whizzing by the Earth a hair’s breath from the surface.  Missing us by only 14,000 miles, well within the 22,300 mile orbit of the Geostationary satellites that orbit around the Earth’s equator.  I wanted to put this in perspective for you with some of the chilling and fascinating facts:
This is approximately the same size as the asteroid that hit the Earth in Russia in Siberia (the “Tunguska Event”) on June 30th 1908.

That impact was equivalent to 1,000 Hiroshima nuclear bombs & knocked down 80 million trees down over an area covering 2,150 square kilometers (830 sq mi).

Had it hit near a population center it would have killed millions of people.

Today, there are approximately 610,000 asteroids that are actively tracked in our Solar System.  This number represents less than one percent of the more than 60 million asteroids that orbit the Sun.
 
To learn more about the threat that these asteroids pose and what Planetary Resources, Inc. and the Asteroid Mining industry can do to help protect the Earth, CLICK HERE.
 
-Chris Lewicki
President & Chief Asteroid Miner

Good for business.

This is unrelated to the meteorite that just impacted. He was talking about 2012 DA14 that is due to have its closest approach with Earth in a few hours.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Hauerg on 02/15/2013 02:44 PM
No, it shattered. Hitting the lower atmosphere at those speeds is like hitting concrete. They are estimating a mass of about 10 tonnes, about a cubic meter in size.

Big things come in small packages ;)
10t and 1m^3 would be more dense than pure Ni.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Orbiter on 02/15/2013 02:45 PM
This came in hauling for sure, 30+ km/s.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Zed_Noir on 02/15/2013 02:46 PM
Here's the location:

(http://media.skynews.com/media/images/generated/2013/2/15/221496/default/v1/map-1-522x293.jpg)

How far away is Baikonur from the impact area? My estimate from quick wikipedia lookup is about 600 km. It's roughly where the first K on the Kazakhstan label on Chris B's map. Scary it was that close.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: R7 on 02/15/2013 02:50 PM
The meteorite didn't detonate.

What meteorite would? Are there left-over chunks of C4 from solar system formation up there, yikes  ;)

Is it confirmed that 2012 DA14 is not related to this? What a coincidence if not.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: go4mars on 02/15/2013 02:54 PM
The Buzzard Coulee one a couple years ago was about the same size (if this is actually 10 tons).  It just happened in a very sparsely populated area.  I spent days walking the strewn-field in that case with the science team.  If it had happened in a city, I suspect it would have been significant injuries.  Luckily, most of the world is unpopulated.  Unfortunately, a lot of that unpopulated area can expand as waves into populated areas.  Also, unfortunately, the geological record shows that regional impacts may be uncomfortably frequent.  Burckle crater is the biggest recent example I am familiar with.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mlindner on 02/15/2013 02:56 PM
NASA Media Channel is answering questions. Seems like they're very unorganized right now. Can only hear half of the conversations (can only hear responses no media questions).

They also seem to be forgetting to turn off the audio channel when they blacked out the screen. Someone asked him offscreen "White house wants more information." Jim Garvin: "Tell them to turn on the damn TV."

http://www.ustream.tv/channel/nasa-media-channel
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mlindner on 02/15/2013 02:59 PM
The meteorite didn't detonate.

What meteorite would? Are there left-over chunks of C4 from solar system formation up there, yikes  ;)

Is it confirmed that 2012 DA14 is not related to this? What a coincidence if not.


Bad astronomy blog is pretty certain because of the large time displacement between the two which would put the two rocks on very different orbits.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mmeijeri on 02/15/2013 03:01 PM
Bad astronomy blog is pretty certain because of the large time displacement between the two which would put the two rocks on very different orbits.

It's a pity no one appears to have responded to Jorge's argument (http://forum.nasaspaceflight.com/index.php?topic=31118.msg1013169#msg1013169) for caution.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mlindner on 02/15/2013 03:05 PM
Bad astronomy blog is pretty certain because of the large time displacement between the two which would put the two rocks on very different orbits.

It's a pity no one appears to have responded to Jorge's argument (http://forum.nasaspaceflight.com/index.php?topic=31118.msg1013169#msg1013169) for caution.

http://www.bbc.co.uk/news/world-europe-21468116

Quote
Prof Alan Fitzsimmons, of the Astrophysics Research Centre at Queen's University Belfast, said there was "almost definitely" no connection.

"One reason is that 2012 DA14 is approaching Earth from the south, and this object hit in the northern hemisphere," he told BBC News.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mmeijeri on 02/15/2013 03:06 PM
He is not responding to Jorge's argument.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Leo E Liptical on 02/15/2013 03:12 PM
I stayed at a Holiday Inn Express last night, so I vote for it having something to do with DA14, regardless or the orbital path they say it took. The timing is tooooo close. Remember, people once thought the world was flat, too. Just sayin...
Mike
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mr. mark on 02/15/2013 03:23 PM
Not to make light of this but, I guess it's time for those asteroid mining companies to use this as possible promo for their asteroid hunting telescopes they're trying to launch.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: ChileVerde on 02/15/2013 03:24 PM
He is not responding to Jorge's argument.

Indeed he is not.  This event is shaping up as a cautionary lesson for everybody.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mr. mark on 02/15/2013 03:29 PM
What are the chances that the asteroid passing close by altered the meteor's trajectory or that the asteroid is a loose configuration with possible out front or trailing debris.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: kevin-rf on 02/15/2013 03:31 PM
Don't worry, I give Obama exactly 3 days to find religion and make a NEO telescope and Mission a national priority.

That's okay, I already saw a Russian news article claiming it was a US weapons test.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: smoliarm on 02/15/2013 03:32 PM
The meteorite didn't detonate. The explosion sounds are pieces of the meteorite going supersonic/hypersonic velocities with the largest piece having the loudest initial bang.

Edit: Large impact crater!
http://www.youtube.com/watch?v=_cd47Q44igI


This video is a scam - it was filmed about 6 years ago at the burning natural gas site somewhere in Kazakhstan. The original video with correct date and place is still on YouTube, I could find ref. The funniest thing is that the gov TV channel, NTV, bought that scam and aired this video :)
-- Do not trust NTV.

The truth is - there are no craters found.
The only impact site reported so far is on the lake Chebarkul, it has perfectly circular shape (8 m in diameter) with prominent ejecta trail of ~ 40 m. This implies that relatively small fragment hit the ice at supersonic speed.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: R7 on 02/15/2013 03:39 PM
That's okay, I already saw a Russian news article claiming it was a US weapons test.

Clearly FUD by the Decepticons that just landed.

The good news seems to be that no fatalities reported, and injuries are mostly cuts and bruises only!

Question: if this thing would have entered in steeper angle would the damage been much greater but localized?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Ben the Space Brit on 02/15/2013 03:55 PM
Another Bolide-style airburst event - this time reported from central Cuba.

Original link from RAI News Italy - (Warning Italian language) (http://www.rainews24.rai.it/it/news.php?newsid=174956)

Translation by GOOGLE TRANSLATE
Quote
Residents of a locality 'in the central region of Cuba said they had seen an object that fell from the sky and exploded with a great noise, which shook the houses of the place: it is learned from testimonies collected by local television. In service published this morning by Rodas, town in the province of Cienfuegos, witnesses described a very bright light that has come to have large size, comparable to that of a bus, before exploding in the sky.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mlindner on 02/15/2013 04:08 PM
http://attivissimo.blogspot.com/2013/02/russian-meteor-path-plotted-in-google.html

Plot of the meteor's path over russia using weather sat images.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: kevin-rf on 02/15/2013 04:09 PM
Well I did see a faint shooting star going north to south while sitting in the hot tub last night.

btw. A link to the news article that claims it was a US weapons test.
http://rt.com/politics/zhirinovsky-meteorite-american-weapon-316/

When this is over, I think we will need a chicken little the sky is falling party thread.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: GM4BRB - 5DecadesinSpace on 02/15/2013 04:11 PM
http://www.youtube.com/watch?v=LDfvsEHztZg#t=29s

http://www.youtube.com/watch?v=SRSrdOfbnHI#t=67s

http://www.youtube.com/watch?v=iCawTYPtehk#t=12s

Hey, can't label me a communist so try 'Coincidence Theorist'.

And then the Big Air-burst over the City.
http://www.youtube.com/watch?v=b7mLUIDGqmw

Source RT.com (Russia Today)
Images and Latest News as it bursts at:

Meteorite hits Russian Urals: Fireball explosion wreaks havoc, over 900 injured
http://rt.com/news/meteorite-crash-urals-chelyabinsk-283/

Nobody Panic!
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mmeijeri on 02/15/2013 04:12 PM
Clearly FUD by the Decepticons that just landed.

Hmm, it looks as if Jesse Ventura was right about Bigelow and his alien cronies. I for one welcome our new inflatable expandable overlords!
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: JohnFornaro on 02/15/2013 04:12 PM
PRI's news release inflated that estimate:

Quote from: Lewicki
Hi there,

As you probably have heard, today, February 15th, a 150-foot (45 meter) asteroid is whizzing by the Earth a hair’s breath from the surface.  ...
 
-Chris Lewicki
President & Chief Asteroid Miner

Good for business.

This is unrelated to the meteorite that just impacted. He was talking about 2012 DA14 that is due to have its closest approach with Earth in a few hours.

Good call.

Still, good for business.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mmeijeri on 02/15/2013 04:23 PM
Visual distance perception of these events is clearly very unreliable. When the meteor is at its brightest, it looks as if it is going to impact very nearby, perhaps even hitting the camera. Once the fireball is over, you can see it is still quite a way off. And judging by the the dispersal of the trail left by the meteorite there must have been a long delay between the impacts and the sonic booms, so most of these clips must have been taken from many tens of kilometers away. Still, the blast wave was enough to do serious damage.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: R7 on 02/15/2013 04:27 PM
Hmm, it looks as if Jesse Ventura was right about Bigelow and his alien cronies. I for one welcome our new inflatable expandable overlords!

There have been alternate theories of the nature of this phenomenon (I guess in US that would be Chuck Norris) :

http://cs6081.userapi.com/v6081385/508f/hhp8_8Hlg7g.jpg

And this one suits so well on NSF  ;D  :

(http://pit.dirty.ru/lepro/2/2013/02/15/57197-102530-4b388aba77729df9c1302ada44ac49d7.png)
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 02/15/2013 04:28 PM
Visual distance perception of these events is clearly very unreliable. When the meteor is at its brightest, it looks as if it is going to impact very nearby, perhaps even hitting the camera. Once the fireball is over, you can see it is still quite a way off. And judging by the the dispersal of the trail left by the meteorite there must have been a large delay between the impacts and the sonic booms, so most of these clips must have been taken from many tens of kilometers away away. Still, the blast wave is enough to do serious damage.
By far the easiest (and maybe most reliable) way to estimate distance would be from delay of the boom.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mmeijeri on 02/15/2013 04:32 PM
Yeah, but that's hard to judge from these clips, since most of them show either the flash or the bang, but not both. Still, that by itself gives you a minimum distance for the flashes. For the bangs you can only to try to guess how long it took people to get outside and start filming, or you could guesstimate the delay by the dispersal of the meteorite trail.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 02/15/2013 04:34 PM
Yeah, but that's hard to judge from these clips, since most of them show either the flash or the bang, but not both. Still, that by itself gives you a minimum distance for the flashes. For the bangs you can only to try to guess how long it took people to get outside and start filming, or you could guesstimate the delay by the dispersal of the meteorite trail.
Also, there are probably quite a few that have the whole thing recorded.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Star One on 02/15/2013 04:37 PM
If this puts the wind up a few politicians to spend some money on telescopes hunting for these objects then all well & good. There was a piece in the new Scientist recently that due to lack of funding we could soon have a blind spot in the hunt for such objects in the Southern Hemisphere.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Ben the Space Brit on 02/15/2013 04:37 PM
http://attivissimo.blogspot.com/2013/02/russian-meteor-path-plotted-in-google.html

Plot of the meteor's path over russia using weather sat images.

Yep, definitely looks like it came out of the north-east.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: R7 on 02/15/2013 04:38 PM
Doesn't a rock of several meters show up on USSTRATCOM screens well before it hits the atmosphere? Or russian equivalent agency?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Chris Bergin on 02/15/2013 04:40 PM
NASA Statement:

According to NASA scientists, the trajectory of the Russian meteorite was significantly different than the trajectory of the asteroid 2012 DA14, making it a completely unrelated object. Information is still being collected about the Russian meteorite and analysis is preliminary at this point. In videos of the meteor, it is seen to pass from left to right in front of the rising sun, which means it was traveling from north to south. Asteroid DA14's trajectory is in the opposite direction, from south to north.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mmeijeri on 02/15/2013 04:43 PM
Aargh, again not responding to Jorge's argument. Chris, could you point a NASA PAO at Jorge's post and ask him to comment?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: smoliarm on 02/15/2013 04:48 PM
That's okay, I already saw a Russian news article claiming it was a US weapons test.

Clearly FUD by the Decepticons that just landed.

The good news seems to be that no fatalities reported, and injuries are mostly cuts and bruises only!

Question: if this thing would have entered in steeper angle would the damage been much greater but localized?

OK, I passed this exam with an A, but it was in 1996. So, I'll try to answer, but wont bet $100 that my answer is 100% correct :)

First, the steep entry angle means early and rapid breakup, multiple detonation events and no debris reaching the ground. Detonations occur too high for any damage on the ground by shock wave.

Second, the shallow angle (which is still flight-terminating) results in slow fragmentation (like one-bite-at-a-time), and SINGLE detonation - if it comes to that, and it's not that strong (as most of the original mass is "chipped" away. A lot of fragments fell to the ground, but all vertically and at sub-sonic speed.

For both above cases, damage on the ground is low, the worst scenario is in the middle.
The present case is obviously in-between - two major explosions, at least one fragment was supersonic on impact. But it is difficult to tell which way (in terms of angle) is the worst.
Let's put it this way - if we take exactly this size rock with the same speed and optimize angle for the lowest possible altitude explosion - the damage will be greater and the area will be wider.

One more thing - it is absolutely correct to call this event "explosion" or "detonation", despite the fact there is no TNT or C4 in the thing. The kinetics and thermodynamics are the same, and the shock wave properties are the same - down to the last equation.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: ugordan on 02/15/2013 04:49 PM
mmeijeri: How do you know they aren't "responding" and that they didn't take that possibility into account? "Significantly different trajectory" and noting the difference between one moving south->north and the other moving north->south.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: a_langwich on 02/15/2013 04:49 PM
The meteorite didn't detonate.

What meteorite would? Are there left-over chunks of C4 from solar system formation up there, yikes  ;)

Frozen ice, methane/other hydrocarbon, rapidly heated.  Not sure what sorts of nitrogen-rich molecules are found across the solar system.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mmeijeri on 02/15/2013 04:54 PM
mmeijeri: How do you know they aren't "responding" and that they didn't take that possibility into account? "Significantly different trajectory" and noting the difference between one moving south->north and the other moving north->south.

I'm not saying they're not taking it into account, just that they're not explicitly saying so or referring to Jorge's argument, so we are still none the wiser.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: ugordan on 02/15/2013 04:58 PM
It's a press release so going technical would just be going over everyone's head. But let's take this north-south thing further. The way I see it, 2012 DA12 would have to be traveling more or less along the plane of the equator and moving north to be able to be bent "downward" south over Russia. However, the trajectory outlined here http://1.bp.blogspot.com/-fcxyLhyuZTc/T15j_Ne1P6I/AAAAAAAABB0/7snMQ6fO6G0/s1600/asteroida.png suggests it's coming in practically pole-to-pole. I see no way to make that trajectory into a north-south one matching this event. YMMV.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: R7 on 02/15/2013 04:58 PM
Thanks Smoliarm, interesting info!

But I just realized something depressing; this event will refuel belief in Nibiru  :-[
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: R7 on 02/15/2013 05:01 PM
The way I see it, 2012 DA12 would have to be traveling more or less along the plane of the equator and moving north to be able to be bent "downward" south over Russia.

http://en.wikipedia.org/wiki/2012_DA14 (http://en.wikipedia.org/wiki/2012_DA14)

Quote
Inclination    10.33°

Not travelling pole to pole, the image you posted seems to be from raised angle.

edit:

(http://upload.wikimedia.org/wikipedia/commons/thumb/f/fb/2012_DA14.ogg/768px--2012_DA14.ogg.jpg)
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mmeijeri on 02/15/2013 05:02 PM
It's a press release so going technical would just be going over everyone's head.

I'm still curious...

Quote
But let's take this north-south thing further. The way I see it, 2012 DA12 would have to be traveling more or less along the plane of the equator and moving north to be able to be bent "downward" south over Russia. However, the trajectory outlined here http://1.bp.blogspot.com/-fcxyLhyuZTc/T15j_Ne1P6I/AAAAAAAABB0/7snMQ6fO6G0/s1600/asteroida.png suggests it's coming in practically pole-to-pole. I see no way to make that trajectory into a north-south one matching this event. YMMV.

My understanding of B-plane targeting is hazy and rusty, but I thought a small nudge at sufficient distance could rotate the Earth-centered plane of an object to basically any orientation. Is that wrong?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: yg1968 on 02/15/2013 05:03 PM
NASA Media Channel is answering questions. Seems like they're very unorganized right now. Can only hear half of the conversations (can only hear responses no media questions).

They also seem to be forgetting to turn off the audio channel when they blacked out the screen. Someone asked him offscreen "White house wants more information." Jim Garvin: "Tell them to turn on the damn TV."

http://www.ustream.tv/channel/nasa-media-channel

That's funny!
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: ugordan on 02/15/2013 05:04 PM
Quote
Inclination    10.33°

Not travelling pole to pole, the image you posted seems to be from raised angle.

That's the heliocentric orbit parameter. Says nothing about the geometry of the Earth flyby.

Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: R7 on 02/15/2013 05:08 PM
That's the heliocentric orbit parameter. Says nothing about the geometry of the Earth flyby.

Huh, we know Earth's inclination and axial tilt. That tell's something.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 02/15/2013 05:23 PM
This building was (partially) destroyed by the blast:
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: kevin-rf on 02/15/2013 05:27 PM
Doesn't a rock of several meters show up on USSTRATCOM screens well before it hits the atmosphere? Or russian equivalent agency?

Remember they are looking for ICBM's and maybe stuff in orbit, so there is a limit to how high and how often they may or may not be looking. If it came in at 15 km a second (could be faster), and lets just guess for hand waving and ignore the angle it came in at and they only look up to a made up number of  600km well it would have been on the screens for only 40 seconds. Enough time to soil one's boxers, but not enough to do much else.

The flight times of ICBM's means you don't have to ping every bit of bit of space several times a second, but once every couple of seconds in the general direction you think they are coming from.

Though to be fair coming from the north east like it did does make one gut check to see if the US lobbed an ICBM ;)
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: R7 on 02/15/2013 05:30 PM
op-ed on CNN

http://edition.cnn.com/2013/02/15/opinion/meteors-colin-stuart-oped/index.html?hpt=hp_c1 (http://edition.cnn.com/2013/02/15/opinion/meteors-colin-stuart-oped/index.html?hpt=hp_c1)

Quote
Meteor shows why it is crucial to keep an eye on the sky


edit: kevin-rf

Quote
600km well it would have been on the screens for only 40 seconds

Yeah, didn't mean as in time to give any warning but have that 40 seconds or even less actual recorded accurate trajectory to compute where it came from instead of estimating from dashboard cam videos.

Quote
Though to be fair coming from the north east like it did does make one gut check to see if the US lobbed an ICBM

As already said lucky the cold war is over, and looney like Zhirinowski isn't in power.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: psloss on 02/15/2013 05:42 PM
NASA Media Channel is answering questions. Seems like they're very unorganized right now. Can only hear half of the conversations (can only hear responses no media questions).

They also seem to be forgetting to turn off the audio channel when they blacked out the screen. Someone asked him offscreen "White house wants more information." Jim Garvin: "Tell them to turn on the damn TV."

http://www.ustream.tv/channel/nasa-media-channel
That's normal usage -- the Media Channel is for larger television-oriented media organizations that can pull feeds directly from satellite (like I think KGW-TV did on the morning of the LDCM launch).  Those orgs usually don't need to get their side of these interviews.

The original topic for the morning satellite block was the 2012 DA-14 flyby; however, interest in this event is much higher.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: kevin-rf on 02/15/2013 05:47 PM
This building was (partially) destroyed by the blast:

Not sure, I saw one pic on rt where a large amount of black smoke was coming out of. I wildly speculate and wonder if it took a direct hit...
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 02/15/2013 05:48 PM
Live updates:
http://www.guardian.co.uk/science/2013/feb/15/meteorite-explodes-over-russian-urals-live-updates

Incredibly surreal event. All of a sudden, all eyes are on space...
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mmeijeri on 02/15/2013 05:51 PM
Not sure, I saw one pic on rt where a large amount of black smoke was coming out of. I wildly speculate and wonder if it took a direct hit...

It seemed to coincide almost exactly with the blast wave, so maybe the blast wave triggered some sort of explosion.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 02/15/2013 05:59 PM
This whole event is incredibly surreal. This is a once-in-a-lifetime event with unbelievable coincidence of a near-miss by a much larger asteroid. The eyes of the world are on space right now.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mlindner on 02/15/2013 06:00 PM
Live updates:
http://www.guardian.co.uk/science/2013/feb/15/meteorite-explodes-over-russian-urals-live-updates

Incredibly surreal event. All of a sudden, all eyes are on space...

Re-linking this image, has a lot of details on the paths of the meteroite and DA14.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Hodapp on 02/15/2013 06:01 PM
This whole event is incredibly surreal. This is a once-in-a-lifetime event with unbelievable coincidence of a near-miss by a much larger asteroid. The eyes of the world are on space right now.

Yeah, maybe NASA should take a page from the political power in charge and not waste a "crisis"!
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: R7 on 02/15/2013 06:07 PM
Re-linking this image, has a lot of details on the paths of the meteroite and DA14.

Approximate path of the russian meteor ... coming straight from the sun??
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Eric Hedman on 02/15/2013 06:08 PM
Let the hearings begin!

http://thehill.com/blogs/blog-briefing-room/news/283427-house-committee-to-hold-hearing-on-asteroids-that-pose-a-potential-threat-to-earth (http://thehill.com/blogs/blog-briefing-room/news/283427-house-committee-to-hold-hearing-on-asteroids-that-pose-a-potential-threat-to-earth)
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: ugordan on 02/15/2013 06:11 PM
Let the hearings begin!

How quick and predictable. Talk about how important it all is until the noise of this event dies down.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Chris Bergin on 02/15/2013 06:14 PM
Feb. 15, 2013

Steve Cole
Headquarters, Washington                             
202-358-0918
stephen.e.cole@nasa.gov

Janet Anderson
Marshall Space Flight Center, Huntsville, Ala.
256-544-0034
janet.l.anderson@nasa.gov

MEDIA ADVISORY: M13-033

NASA EXPERTS DISCUSS RUSSIA METEOR IN MEDIA TELECONFERENCE TODAY

WASHINGTON -- NASA experts will hold a teleconference for news media
at 4 p.m. EST today to discuss a meteor that streaked through the
skies over Russia's Urals region this morning.

Scientists have determined the Russia meteor is not related to
asteroid 2012 DA14 that will pass safely pass Earth today at a
distance of more than 17,000 miles. Early assessments of the Russia
meteor indicate it was about one-third the size of 2012 DA14 and
traveling in a different direction.

Panelists for the teleconference are:
-- Bill Cooke, lead for the Meteoroid Environments Office at NASA's
Marshall Space Flight Center in Huntsville, Ala.
-- Paul Chodas, research scientist in the Near Earth Object Program
Office at NASA's Jet Propulsion Laboratory in Pasadena, Calif.

News media interested in participating should dial 888-843-7186 and
use the passcode METEOR.

The teleconference will be carried live online at:

http://www.nasa.gov/newsaudio
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: bubbagret on 02/15/2013 06:16 PM
NASA is now suggesting possibly 15 meters...

http://www.nasa.gov/topics/solarsystem/features/russianmeteor.html
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: brtbrt on 02/15/2013 06:30 PM
- Knock, Knock!
- Who's there?
-Chelyabinsk Meteor. Got lonely out here, so I decided to drop by and check on how your space programs are doing. When are you guys going to come and visit our neighbourhood?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 02/15/2013 06:32 PM
Let the hearings begin!

How quick and predictable. Talk about how important it all is until the noise of this event dies down.
Of course it's predictable. And yeah, advocates for space that want to get the public engaged have /got/ to learn to take advantage of situations like this because they are rare and USUALLY squandered.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: R7 on 02/15/2013 06:32 PM
NASA is now suggesting possibly 15 meters...

http://www.nasa.gov/topics/solarsystem/features/russianmeteor.html

Quote
it is seen to pass from left to right in front of the rising sun, which means it was traveling from north to south

mlinder posted a link of weather sat image of the contrail superimposed over google maps, path is pretty much from ENE to WSW.

There's also videos where apparent movement on the sky is from right to left.

http://www.youtube.com/watch?feature=player_embedded&v=zJ-Y7vhS1JE (http://www.youtube.com/watch?feature=player_embedded&v=zJ-Y7vhS1JE)
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 02/15/2013 06:37 PM
Let the hearings begin!

http://thehill.com/blogs/blog-briefing-room/news/283427-house-committee-to-hold-hearing-on-asteroids-that-pose-a-potential-threat-to-earth (http://thehill.com/blogs/blog-briefing-room/news/283427-house-committee-to-hold-hearing-on-asteroids-that-pose-a-potential-threat-to-earth)
It does make NASA less of a target for cuts (from just a social/political perspective).

This is a legitimate threat to humanity and our nation. As real as North Korea or Iran.

Sometimes I really have to wonder about space advocates who talk about how the public doesn't care and either how that's unfair/stupid or how it's inevitable. And when space DOES enter the public's eye, they brush it off, poo-poo it, and usually don't take the opportunity to educate people.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mlindner on 02/15/2013 06:42 PM
Found a video with a full length meteor going through atmosphere to shockwave impact.

Meteorite passes by at 4:40 in video.
Shockwave impact at 7:01 in video.
Thats a dramatic 2m21s in time delay, or 48km away assuming speed of sound at sea level.
The angle is also oblique as well, but we should be able to guesstimate the altitude from that.


http://www.youtube.com/watch?v=gQ6Pa5Pv_io
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: yg1968 on 02/15/2013 06:44 PM
Let the hearings begin!

How quick and predictable. Talk about how important it all is until the noise of this event dies down.

There is a couple of Republicans members on the House Space and Science committee that brings up this topic at every NASA hearing.  So I am not surprised at the fact that they are looking into it now. It's a good thing in my opinion. 
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: alexterrell on 02/15/2013 06:49 PM
What are the policy implications?

This is the No 1 new item around the World. It makes a very strong case for building space capabilities. Some impacts:

- Improved funding for space telescopes - like this one http://www.guardian.co.uk/commentisfree/2013/feb/15/meteor-strike-asteroid-pass-sentinel-telescope?commentpage=1 (http://www.guardian.co.uk/commentisfree/2013/feb/15/meteor-strike-asteroid-pass-sentinel-telescope?commentpage=1)
- More international cooperation?
- International funding of space guard projects?
- Manned missions to NEOs?
- More public support for NASA?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: ugordan on 02/15/2013 07:01 PM
It's a good thing in my opinion. 

Oh, I agree there, but talk is cheap.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 02/15/2013 07:10 PM
It's a good thing in my opinion. 

Oh, I agree there, but talk is cheap.
What are you doing about it?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: ugordan on 02/15/2013 07:15 PM
Found a video with a full length meteor going through atmosphere to shockwave impact.

Meteorite passes by at 4:40 in video.
Shockwave impact at 7:01 in video.
Thats a dramatic 2m21s in time delay, or 48km away assuming speed of sound at sea level.
The angle is also oblique as well, but we should be able to guesstimate the altitude from that.


http://www.youtube.com/watch?v=gQ6Pa5Pv_io

Wow, thanks for the find! Watching this, I'll have to revise my energy estimate. Producing that amount of bang and window movement at that distance, this couldn't have been produced by a low kiloton equivalent.

Dare I say around 1 megaton event?

Edit: note that this is also probably the first video that shows 2 or 3 distinct fragments after the bright breakup.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: notsorandom on 02/15/2013 07:16 PM
Let the hearings begin!

http://thehill.com/blogs/blog-briefing-room/news/283427-house-committee-to-hold-hearing-on-asteroids-that-pose-a-potential-threat-to-earth (http://thehill.com/blogs/blog-briefing-room/news/283427-house-committee-to-hold-hearing-on-asteroids-that-pose-a-potential-threat-to-earth)
It does make NASA less of a target for cuts (from just a social/political perspective).

This is a legitimate threat to humanity and our nation. As real as North Korea or Iran.

Sometimes I really have to wonder about space advocates who talk about how the public doesn't care and either how that's unfair/stupid or how it's inevitable. And when space DOES enter the public's eye, they brush it off, poo-poo it, and usually don't take the opportunity to educate people.
It doesn't surprise me all that much that threats from NEOs are not talked about that much by space advocates. There is little to no relationship between asteroid threats and the various issues people tent to be passionate about (human spaceflight, Mars, etc.).
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: ugordan on 02/15/2013 07:17 PM
What are you doing about it?

Nothing. Not a U.S. taxpayer so my opinion is inconsequential for all practical purposes.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mmeijeri on 02/15/2013 07:18 PM
With that second image, I'm satisfied they're unrelated.

Hmm, exquisite timing then.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Lar on 02/15/2013 07:20 PM
It doesn't surprise me all that much that threats from NEOs are not talked about that much by space advocates. There is little to no relationship between asteroid threats and the various issues people tent to be passionate about (human spaceflight, Mars, etc.).

Really doing a good job of defense requires a LOT of eyes watching (to find) and pretty serious space based infrastructure (to remediate). We spacers should be riding this pony because space based infrastructure/manufacturing is the key to everything else.

IMHO anyway
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Star One on 02/15/2013 07:21 PM
With that second image, I'm satisfied they're unrelated.

Hmm, exquisite timing then.

Useful timing as far as getting the issue up the agenda.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: R7 on 02/15/2013 07:23 PM
Dare I say around 1 megaton event?

Unlikely. Estimates have been ~10 tonnes and 20km/s, that gives 'just' 2TJ, little shy of half kiloton worth of KE.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: smoliarm on 02/15/2013 07:24 PM
Found a video with a full length meteor going through atmosphere to shockwave impact.

Meteorite passes by at 4:40 in video.
Shockwave impact at 7:01 in video.
Thats a dramatic 2m21s in time delay, or 48km away assuming speed of sound at sea level.
The angle is also oblique as well, but we should be able to guesstimate the altitude from that.


One more full video of event allowing more accurate estimate, since the location is known:
http://www.youtube.com/watch?v=efvP-RRuJuA
Local time is in the low-right corner
The camera is in the northern outskirt of the city, no more than 10 km from epicenter.
First flash = 9:20:03
Second flash = 9:20:05 (major)
Shock wave = 9:22:22
Delay = 137 sec.
Now, on speed of sound - it was minus 13 C, altitude ~ 205 m. I did simple graph approximation for [0.25 -- 40 km] and got average 305 m/sec. This gives distance of 41.8 km. Assuming the range to epicenter as 10 km, the altitude of explosion was 40.6 km
Given the range of 10 km is a max estimate, I'd give the final number as 41 +/- 0.5 km


Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: jcm on 02/15/2013 07:28 PM
Dare I say around 1 megaton event?

Unlikely. Estimates have been ~10 tonnes and 20km/s, that gives 'just' 2TJ, little shy of half kiloton worth of KE.

New estimates based on infrasound stations (and I don't know how they
derive the result) claim 15m dia, 7000 tonnes, and hundreds of kT
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: ugordan on 02/15/2013 07:28 PM
Unlikely. Estimates have been ~10 tonnes and 20km/s, that gives 'just' 2TJ, little shy of half kiloton worth of KE.

No way was this amount of bang produced by 0.5 KT. NASA are now estimating the diameter at 15 m and mass at about 7000 tons. http://www.nasa.gov/mission_pages/asteroids/news/asteroid20130215.html
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: jcm on 02/15/2013 07:29 PM
I agree with Jorge's latest that it seems unrelated - unless maybe it aerobraked in the southern hemisphere unseen  and ended up making half an orbit, like an Apollo/Zond skip reentry
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: R7 on 02/15/2013 07:33 PM
No way was this amount of bang produced by 0.5 KT. NASA are now estimating the diameter at 15 m and mass at about 7000 tons.

I did wonder that 0.5kt sound low. But 7000 tons .. wow!

edit: about the mlinder second image, isn't it weird that the approximated meteor trajectory is almost straight from the sun? Things flying such orbit should have had insane velocity, no? Or maybe I just read it incorrectly.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mmeijeri on 02/15/2013 07:35 PM
Any idea on whether the alleged event in Cuba is real? Amusingly, there could still be a link between the Cuban event, if it happened, and either the big asteroid or the Russian meteor, but not both, now that we know that the latter two are unrelated. Or the Cuban event could be a false report, which is what I’m inclined to believe.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: kevin-rf on 02/15/2013 07:35 PM
Let the hearings begin!

How quick and predictable. Talk about how important it all is until the noise of this event dies down.
So should we be bracing for a law banning Assault Meteors?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: ChileVerde on 02/15/2013 07:53 PM
I agree with Jorge's latest that it seems unrelated - unless maybe it aerobraked in the southern hemisphere unseen  and ended up making half an orbit, like an Apollo/Zond skip reentry

I agree that it's looking like they're unrelated, but a certain amount of wait-and-see might still be warranted. Jay Melosh was just on NPR Science Friday and was hedging a little bit on the coincidental nature of the two events.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Lee Jay on 02/15/2013 07:55 PM
I agree with Jorge's latest that it seems unrelated - unless maybe it aerobraked in the southern hemisphere unseen  and ended up making half an orbit, like an Apollo/Zond skip reentry

Which it couldn't do at 18km/second at the second entry, correct?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Blackstar on 02/15/2013 07:56 PM
Let the hearings begin!

How quick and predictable. Talk about how important it all is until the noise of this event dies down.

And maybe everybody should just stop and take a few breaths.

We could start by putting this in perspective. How many people have died in the past decade from seismic-related events? How much money is being spent to predict those?

Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: kevin-rf on 02/15/2013 08:00 PM

And maybe everybody should just stop and take a few breaths.

We could start by putting this in perspective. How many people have died in the past decade from seismic-related events? How much money is being spent to predict those?


Considering the Italians just put a bunch of seismic scientists on trial for failing to predict a killer earthquake, that may be a poor example.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Blackstar on 02/15/2013 08:04 PM

And maybe everybody should just stop and take a few breaths.

We could start by putting this in perspective. How many people have died in the past decade from seismic-related events? How much money is being spent to predict those?


Considering the Italians just put a bunch of seismic scientists on trial for failing to predict a killer earthquake, that may be a poor example.

It's an excellent example. But please, feel free to run around screaming if it makes you feel better...
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Mark S on 02/15/2013 08:04 PM

And maybe everybody should just stop and take a few breaths.

We could start by putting this in perspective. How many people have died in the past decade from seismic-related events? How much money is being spent to predict those?


Considering the Italians just put a bunch of seismic scientists on trial for failing to predict a killer earthquake, that may be a poor example.

Convicted, actually, if I recall correctly.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Blackstar on 02/15/2013 08:09 PM
Anybody seriously interested in the issue of searching for asteroids and what to do about deflecting them from hitting Earth can check out this study from 2010:

http://www.nap.edu/catalog.php?record_id=12842

Free download.

Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: jcm on 02/15/2013 08:09 PM
I agree with Jorge's latest that it seems unrelated - unless maybe it aerobraked in the southern hemisphere unseen  and ended up making half an orbit, like an Apollo/Zond skip reentry

Which it couldn't do at 18km/second at the second entry, correct?

Yes, the second entry would be more like 7 km/s, but we don't actually know
what its speed was
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: rdale on 02/15/2013 08:14 PM
Considering the Italians just put a bunch of seismic scientists on trial for failing to predict a killer earthquake, that may be a poor example.

Convicted, actually, if I recall correctly.

Part of the reason they went on trial is because they told their citizens not to bother preparing for earthquakes and enjoy a glass of wine. Totally unrelated.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 02/15/2013 08:14 PM
What are you doing about it?

Nothing. Not a U.S. taxpayer so my opinion is inconsequential for all practical purposes.
Well, you certainly could do whatever in your own country as well. That's just as important.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: smoliarm on 02/15/2013 08:16 PM
Dare I say around 1 megaton event?

Unlikely. Estimates have been ~10 tonnes and 20km/s, that gives 'just' 2TJ, little shy of half kiloton worth of KE.

New estimates based on infrasound stations (and I don't know how they
derive the result) claim 15m dia, 7000 tonnes, and hundreds of kT


7000 tonnes ... "Wow" seems not enough :)
I have no idea how this estimate was obtained, but I'm sure it's beyond my expertize.

Lets compare with records --
Sikhote-Alin meteorite (belongs to the top 10 largest meteorites):
estimated mass = 70 to 100 tonnes
Recovered mass = 23 t
entry speed = 14 km/sec
more than a hundred of craters and severe damage to forest in epicenter.
It fell in unpopulated remote area, but the sound was heard 300 km away
Bright flash was seen from Vladivostok, some 450 km away.

today:
In Miass and Zlatoust (90 and 110 km to the west from Chelyabinsk) nobody heard a sound, they just enjoy a silent show.
in the epicenter - broken windows and one abundoned building damaged by shock wave.
no large craters reported so far. The only reported fragments are about 0.5 cm...
estimated entry speed 15-20 km/sec
and yet on the top, it is 7000 tonnes...

If so - it was very gentle and well behaving meteorite :)
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Blackstar on 02/15/2013 08:17 PM
What are you doing about it?

Nothing. Not a U.S. taxpayer so my opinion is inconsequential for all practical purposes.
Well, you certainly could do whatever in your own country as well. That's just as important.

Or you could go here and donate:

http://b612foundation.org/donate/

Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mlindner on 02/15/2013 08:22 PM
Dare I say around 1 megaton event?

Unlikely. Estimates have been ~10 tonnes and 20km/s, that gives 'just' 2TJ, little shy of half kiloton worth of KE.

New estimates based on infrasound stations (and I don't know how they
derive the result) claim 15m dia, 7000 tonnes, and hundreds of kT


7000 tonnes ... "Wow" seems not enough :)
I have no idea how this estimate was obtained, but I'm sure it's beyond my expertize.

Lets compare with records --
Sikhote-Alin meteorite (belongs to the top 10 largest meteorites):
estimated mass = 70 to 100 tonnes
Recovered mass = 23 t
entry speed = 14 km/sec
more than a hundred of craters and severe damage to forest in epicenter.
It fell in unpopulated remote area, but the sound was heard 300 km away
Bright flash was seen from Vladivostok, some 450 km away.

today:
In Miass and Zlatoust (90 and 110 km to the west from Chelyabinsk) nobody heard a sound, they just enjoy a silent show.
in the epicenter - broken windows and one abundoned building damaged by shock wave.
no large craters reported so far. The only reported fragments are about 0.5 cm...
estimated entry speed 15-20 km/sec
and yet on the top, it is 7000 tonnes...

If so - it was very gentle and well behaving meteorite :)

Listening to the presser, they used infrasound detectors that were meant to detect nuclear airburst explosions. I would guess they are left from technology that would have detected the U.S. attacking the U.S.S.R. Scary.

They stated it had a very shallow entry path so drew out the energy deposition. Also, atmospherics can have a huge effect at bending the sound away or focusing it in depending on the current state of the atmosphere.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 02/15/2013 08:25 PM
Let the hearings begin!

http://thehill.com/blogs/blog-briefing-room/news/283427-house-committee-to-hold-hearing-on-asteroids-that-pose-a-potential-threat-to-earth (http://thehill.com/blogs/blog-briefing-room/news/283427-house-committee-to-hold-hearing-on-asteroids-that-pose-a-potential-threat-to-earth)
It does make NASA less of a target for cuts (from just a social/political perspective).

This is a legitimate threat to humanity and our nation. As real as North Korea or Iran.

Sometimes I really have to wonder about space advocates who talk about how the public doesn't care and either how that's unfair/stupid or how it's inevitable. And when space DOES enter the public's eye, they brush it off, poo-poo it, and usually don't take the opportunity to educate people.
It doesn't surprise me all that much that threats from NEOs are not talked about that much by space advocates. There is little to no relationship between asteroid threats and the various issues people tent to be passionate about (human spaceflight, Mars, etc.).
Well, there actually are some similarities between human spaceflight missions and NEO threats. Early deep space missions (the Gemini of a Mars architecture) currently target NEOs for visits. In addition to any intensive study of a NEO from a HSF mission (which may not win by itself in a cost/benefit analysis against an unmanned mission or ten), if we're going to deflect an asteroid, having the ability to deploy a very large spacecraft using solar-electric propulsion to station-keep near the asteroid (and the proximity ops of asteroid missions) is quite relevant indeed, even though the actual deflection spacecraft would surely be unmanned.

But the propulsion technology and scale needed for a significant gravity-tractor craft would be on the same level. And, of course, it fits in well with lunar and Martian operations as well (for tug and transfer vehicle work).

The problem, however, is apparently a lot of HSF advocates are kind of prejudiced against any kind of asteroid mission for whatever reason, even though it's arguably easier to justify from a fundamental perspective.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mmeijeri on 02/15/2013 08:26 PM
I agree with Jorge's latest that it seems unrelated - unless maybe it aerobraked in the southern hemisphere unseen  and ended up making half an orbit, like an Apollo/Zond skip reentry

Amazingly, major orbital plane changes as a result of passage through the atmosphere have happened before:

1972 Great Daylight Fireball (http://en.wikipedia.org/wiki/1972_Great_Daylight_Fireball)
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: catdlr on 02/15/2013 08:28 PM
Live updates:
http://www.guardian.co.uk/science/2013/feb/15/meteorite-explodes-over-russian-urals-live-updates

Incredibly surreal event. All of a sudden, all eyes are on space...

In the video, at 24 secs, shows a large door being blown in by the force of the blast.  Quite sobrering  :o
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: kevin-rf on 02/15/2013 08:42 PM
Listening to the presser, they used infrasound detectors that were meant to detect nuclear airburst explosions. I would guess they are left from technology that would have detected the U.S. attacking the U.S.S.R. Scary.
Actually the main purpose of the US infrasound network (which is what NASA is using for these estimates) is it is part of the network (includes other tech) the US uses to detect secret nuclear testing by other parties (such as post Cold War entities like Iran, N. Korea, Pakistan, India, Manchester United).

During the Cold War, once the US or USSR was attacked, it would have been to late to analyze the data from the network. It is still viable today, and is very viable for characterizing large impact events.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: ChileVerde on 02/15/2013 08:43 PM

Listening to the presser, they used infrasound detectors that were meant to detect nuclear airburst explosions. I would guess they are left from technology that would have detected the U.S. attacking the U.S.S.R. Scary.

No, they're part of the nuclear test ban monitoring system:

http://www.ctbto.org/verification-regime/monitoring-technologies-how-they-work/infrasound-monitoring/
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Blackstar on 02/15/2013 08:44 PM
Listening to the presser, they used infrasound detectors that were meant to detect nuclear airburst explosions. I would guess they are left from technology that would have detected the U.S. attacking the U.S.S.R. Scary.
Actually the main purpose of the US infrasound network (which is what NASA is using for these estimates) is it is part of the network (includes other tech) the US uses to detect secret nuclear testing by other parties (such as post Cold War entities like Iran, N. Korea, Pakistan, India, Manchester United).

During the Cold War, once the US or USSR was attacked, it would have been to late to analyze the data from the network. It is still viable today, and is very viable for characterizing large impact events.

I believe it is part of arms limitation treaty monitoring, and my guess (and yeah, I'm too lazy to look it up right now) is that the US and Russia have an agreement that each country has access to the data from sensors in the other country.

I also vaguely remember that there is an entirely separate network, possibly run by the United Nations. They're not linked. Anyway, there should be quite a bit of data that will take awhile to crunch.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mlindner on 02/15/2013 08:49 PM
Looks like they found a hole in a lake where they think it landed.

More details here:

http://www.slate.com/blogs/bad_astronomy/2013/02/15/russian_meteorite_fragment_may_have_fallen_in_frozen_lake.html
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mlindner on 02/15/2013 08:54 PM
Also, some seismic data.

http://earthquake.usgs.gov/monitoring/operations/station.php?network=IU&station=MAKZ#heliplot
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: R7 on 02/15/2013 08:54 PM
I agree with Jorge's latest that it seems unrelated - unless maybe it aerobraked in the southern hemisphere unseen  and ended up making half an orbit, like an Apollo/Zond skip reentry

Amazingly, major orbital plane changes as a result of passage through the atmosphere have happened before:

1972 Great Daylight Fireball (http://en.wikipedia.org/wiki/1972_Great_Daylight_Fireball)

But if the thing would have aerobraked elsewhere wouldn't that have lit up SBIRS screens big time?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mmeijeri on 02/15/2013 08:57 PM
Probably, so I don't think that's what happened here, I'm just amazed that we have documented examples.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: yg1968 on 02/15/2013 08:57 PM
It's a good thing in my opinion. 

Oh, I agree there, but talk is cheap.

There is some efforts that are being made. See this link (the survey of NEAs larger than 1 km is not yet completed from what I understand):

http://impact.arc.nasa.gov/intro_faq.cfm

Quote
What is the government doing about it?

The US Congress held hearings to investigate the impact hazard in 1993, 1998, and 2002, and both NASA and the US Air Force are supporting surveys to discover NEOs. In 1998 NASA formally initiated the Spaceguard Survey by adopting the objective of finding 90% of the NEAs larger than 1 km diameter within the next decade (that is, before the end of 2008). In 1998 NASA also created a NEO Program Office, and today $3-4 million per year is being spent on NASA-supported NEO searches and orbit calculations. Other governments have expressed concern about the NEO hazard, but none has yet funded any extensive surveys or related defense research. A private Spaceguard Foundation based in Europe promotes NEO surveys internationally, and further interest on an international basis is provided by the International Astronomical Union, the International Council of Scientific Unions, and the United Nations.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: notsorandom on 02/15/2013 08:58 PM
Let the hearings begin!

http://thehill.com/blogs/blog-briefing-room/news/283427-house-committee-to-hold-hearing-on-asteroids-that-pose-a-potential-threat-to-earth (http://thehill.com/blogs/blog-briefing-room/news/283427-house-committee-to-hold-hearing-on-asteroids-that-pose-a-potential-threat-to-earth)
It does make NASA less of a target for cuts (from just a social/political perspective).

This is a legitimate threat to humanity and our nation. As real as North Korea or Iran.

Sometimes I really have to wonder about space advocates who talk about how the public doesn't care and either how that's unfair/stupid or how it's inevitable. And when space DOES enter the public's eye, they brush it off, poo-poo it, and usually don't take the opportunity to educate people.
It doesn't surprise me all that much that threats from NEOs are not talked about that much by space advocates. There is little to no relationship between asteroid threats and the various issues people tent to be passionate about (human spaceflight, Mars, etc.).
Well, there actually are some similarities between human spaceflight missions and NEO threats. Early deep space missions (the Gemini of a Mars architecture) currently target NEOs for visits. In addition to any intensive study of a NEO from a HSF mission (which may not win by itself in a cost/benefit analysis against an unmanned mission or ten), if we're going to deflect an asteroid, having the ability to deploy a very large spacecraft using solar-electric propulsion to station-keep near the asteroid (and the proximity ops of asteroid missions) is quite relevant indeed, even though the actual deflection spacecraft would surely be unmanned.

But the propulsion technology and scale needed for a significant gravity-tractor craft would be on the same level. And, of course, it fits in well with lunar and Martian operations as well (for tug and transfer vehicle work).

The problem, however, is apparently a lot of HSF advocates are kind of prejudiced against any kind of asteroid mission for whatever reason, even though it's arguably easier to justify from a fundamental perspective.
I agree that a human BEO program would give us more information and tools to better deal with this threat. However HSF isn't necessary to characterize and significantly mitigate the threat. An automated space based observation program can significantly increase the detection chance for a fraction of the cost of a human BEO mission. Even if there was only a warning of a few days or hours it would be enough to have people take cover or evacuate the impact area. If the objective is to mitigate the threat posed by asteroid impacts then I don't think one can justify the added cost of involving HSF, and I say that as a big supporter of HSF in general. Not that I am saying you are saying otherwise. I think we are mostly in agreement.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: psloss on 02/15/2013 09:03 PM
New estimates based on infrasound stations (and I don't know how they
derive the result) claim 15m dia, 7000 tonnes, and hundreds of kT
SpaceWeather.com is quoting 300 kT, maybe from the NASA teleconference...anyone happen to record that audio?

From: http://www.spaceweather.com/
Quote
NASA scientists have conducted a preliminary analysis of the event. "Here is what we know so far," says Bill Cooke, head of NASA's Meteoroid Environment Office. "The asteroid was about 15 meters in diameter and weighed approximately 7000 metric tons. It struck Earth's atmosphere at 40,000 mph (18 km/s) and broke apart about 12 to 15 miles (20 to 25 km) above Earth's surface. The energy of the resulting explosion was in the vicinity of 300 kilotons of TNT."
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: ChileVerde on 02/15/2013 09:15 PM
Also, some seismic data.

http://earthquake.usgs.gov/monitoring/operations/station.php?network=IU&station=MAKZ#heliplot

Very interesting. I wonder if the continuing signal in the ~hour after the event is related.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mlindner on 02/15/2013 09:18 PM
New estimates based on infrasound stations (and I don't know how they
derive the result) claim 15m dia, 7000 tonnes, and hundreds of kT
SpaceWeather.com is quoting 300 kT, maybe from the NASA teleconference...anyone happen to record that audio?

From: http://www.spaceweather.com/
Quote
NASA scientists have conducted a preliminary analysis of the event. "Here is what we know so far," says Bill Cooke, head of NASA's Meteoroid Environment Office. "The asteroid was about 15 meters in diameter and weighed approximately 7000 metric tons. It struck Earth's atmosphere at 40,000 mph (18 km/s) and broke apart about 12 to 15 miles (20 to 25 km) above Earth's surface. The energy of the resulting explosion was in the vicinity of 300 kilotons of TNT."


I didn't record it, but that 300 kT is the number they gave. Rather they said between 300-500 kT. They actually gave a callback number to listen to a replay of the teleconference: 888-562-0218
I just tried it and it works.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Blackstar on 02/15/2013 09:29 PM
There is some efforts that are being made. See this link (the survey of NEAs larger than 1 km is not yet completed from what I understand):


The requirement was for 90%. They are at 95%. They are for all intents and purposes complete. You can never get to 100%.

There is a requirement for searching for 140 meter NEOs. That's nowhere near done (I think they're at no more than 5%). See the report I linked to earlier for more details.

Frankly, NASA doesn't want to do this, and nobody really wants to do this. A few members of Congress slipped some language into bills many years ago requiring NASA to do it, but nobody provided any extra money for them to do it. That's why it's largely not getting done. Simply put, the people who run the country do not think that this is an important issue, or even a minor issue, and never have.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Dalhousie on 02/15/2013 09:30 PM

Listening to the presser, they used infrasound detectors that were meant to detect nuclear airburst explosions. I would guess they are left from technology that would have detected the U.S. attacking the U.S.S.R. Scary.

There is a world wide network of these stations monitoring for clandestine tests.  It would be interesting to see what the other stations picked up.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Space Frog on 02/15/2013 09:33 PM
Regardless of whether the Planetary Defense system will involve HSF or not, if the powers that be can be goaded into ponying up some money for Planetary Defense in response to this event, it will benefit all aspects of spaceflight.  More jobs, higher flight rates, more grants, more hardware.  Space Enthusiasts should really go chicken-little on this event and write dramatic letters to their congresscritters, because something this dramatic doesn't happen very often and politics is (unfortunately) all about making the most of every opportunity.  The next rock could hit Chicago.  And it could be bigger. 
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 02/15/2013 09:35 PM
There is some efforts that are being made. See this link (the survey of NEAs larger than 1 km is not yet completed from what I understand):


The requirement was for 90%. They are at 95%. They are for all intents and purposes complete. You can never get to 100%.

There is a requirement for searching for 140 meter NEOs. That's nowhere near done (I think they're at no more than 5%). See the report I linked to earlier for more details.

Frankly, NASA doesn't want to do this, and nobody really wants to do this. A few members of Congress slipped some language into bills many years ago requiring NASA to do it, but nobody provided any extra money for them to do it. That's why it's largely not getting done. Simply put, the people who run the country do not think that this is an important issue, or even a minor issue, and never have.
There's also never (during the space age) been such a pertinent, documented case of why it is important, and probably has never been such public attention to the topic, either.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Silmfeanor on 02/15/2013 09:37 PM
I agree with the preceding posts - this is a very damaging event, but we can and should be glad it isn't worse. So far no deaths reported. I hope the shock of this opens up some money for spaceflight in general, be it telescopes, satellites or full-blown interception missions.

It could have been much worse. Imagine what would have happened if this was above New York - just imagine the consequences. Don't want to wait for something like that to happen - better cough up some money by this event, which can be regarded as some sort of wake-up call, being the most damaging meteorite event in recorded history of mankind...
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: rdale on 02/15/2013 10:02 PM
What would you cough up money for? Can these rocks be detected, let alone protected, for any amount of money that would be just a slice of the current Homeland Security budget? When it comes to a hazard vulnerability analysis, this incident does nothing to move meteor attacks up the list.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robert Thompson on 02/15/2013 10:10 PM
My Tweet to B612, and the only thing I'll post here,
"@RexHarrisonsHat @B612foundation I won't contribute until B612's website lists contributors by name. This is too important for anonymity."
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 02/15/2013 10:12 PM
What would you cough up money for? Can these rocks be detected, let alone protected, for any amount of money that would be just a slice of the current Homeland Security budget? When it comes to a hazard vulnerability analysis, this incident does nothing to move meteor attacks up the list.
Yes, they can. Scale up aperture, pick the right wavelength, pick the right orbit.how much money do you got? And you really want to compare this to the likes of the TSA?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: JimO on 02/15/2013 10:13 PM
Quite a contrail, too.  Must have been a lot of water and other volatiles, perhaps a small comet?

I don't think the trail was particulates from the object, but atmospheric disruption from the plasma wave. Both normal and [sadly] abnormal orbiter entries at that altitude created similar persistent trails, as I saw with my own eyes over Texas.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: JimO on 02/15/2013 10:16 PM
I agree with the preceding posts - this is a very damaging event, but we can and should be glad it isn't worse. So far no deaths reported. ...

It is prudent to make this point: "SO FAR". Considering the force of the blast in a city at some distance from the sub-blast point, it's too soon to tell what transpired in more rural areas that suffered greater blast and thermal loads.

It's not like you can text out -- 'Everybody who's dead, raise your hand."
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: ChileVerde on 02/15/2013 10:26 PM
Also, some seismic data.

http://earthquake.usgs.gov/monitoring/operations/station.php?network=IU&station=MAKZ#heliplot

I've been digging around in earthquake.usgs.gov and find that the event produced seismic signals as far away as Iowa, perhaps not surprisingly.  There was also a fairly widespread signal about ten minutes before the initial one from Chelyabinsk that was detected strongly in New Zealand, Australia, Hawaii and McMurdo Sound. I suspect this was a coincidentally timed earthquake, but mention it FWIW>

Edit: Attach zipped file of seismograms from various places around the globe. Again FWIW.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: fatjohn1408 on 02/15/2013 10:46 PM
Could it be that this was once a companion of 2012 DA14 but then grazed the atmosphere of the Earth slightly, which altered it's orbit?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Nittany Lion on 02/15/2013 11:07 PM
What would you cough up money for? Can these rocks be detected, let alone protected, for any amount of money that would be just a slice of the current Homeland Security budget? When it comes to a hazard vulnerability analysis, this incident does nothing to move meteor attacks up the list.

Agreed.

Going from 95% of 1 km and 5% of 140 meter (the current survey status according to Blackstar) to 100% of 15 meter sounds like a colossal effort. Add to that some sort of deflection capability and you’re probably talking $500 billion.

The observed frequency of need is one zero-fatality air burst per century, and one extinction event per 65 million years.

Wouldn’t it be better to spend the money developing the capability to deflect hurricanes and tornadoes? Lotta people gonna think that way.

Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: jcm on 02/15/2013 11:10 PM
There is some efforts that are being made. See this link (the survey of NEAs larger than 1 km is not yet completed from what I understand):


The requirement was for 90%. They are at 95%. They are for all intents and purposes complete. You can never get to 100%.

There is a requirement for searching for 140 meter NEOs. That's nowhere near done (I think they're at no more than 5%). See the report I linked to earlier for more details.

Frankly, NASA doesn't want to do this, and nobody really wants to do this. A few members of Congress slipped some language into bills many years ago requiring NASA to do it, but nobody provided any extra money for them to do it. That's why it's largely not getting done. Simply put, the people who run the country do not think that this is an important issue, or even a minor issue, and never have.

They are not 95% complete for things inside 1AU, that you only get to see in the daytime - and things with 1AU aphelia could still hit us
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: sanman on 02/15/2013 11:24 PM
USA Today says "a force of 20 Hiroshima bombs"

http://www.usatoday.com/story/news/world/2013/02/15/russia-meteorite/1921991/

(http://paranoidnews.org/wp-content/uploads/2011/06/Asteroid-Of-Death.jpg)
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mlindner on 02/15/2013 11:30 PM
USA Today says "a force of 20 Hiroshima bombs"

http://www.usatoday.com/story/news/world/2013/02/15/russia-meteorite/1921991/

(http://paranoidnews.org/wp-content/uploads/2011/06/Asteroid-Of-Death.jpg)

Yes thats correct they stated between 300 - 500 kT explosion. Hiroshima was 16 kT. So its 19 - 31 Hiroshima bombs.

I also have to say that image is hilarious. I burst out laughing. My dad loved it as well considering he grew up watching those at the movies.

Edit: Reading the article, its full of inaccuracies and contradictions of information I've seen elsewhere. Falling meteorite debris did not break windows in 3000 buildings...
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Dalhousie on 02/15/2013 11:31 PM
Frankly, NASA doesn't want to do this, and nobody really wants to do this. A few members of Congress slipped some language into bills many years ago requiring NASA to do it, but nobody provided any extra money for them to do it. That's why it's largely not getting done. Simply put, the people who run the country do not think that this is an important issue, or even a minor issue, and never have.

And they never will until a substantial number of people are killed.  Much the same happened with the Indian Ocean tsunami network.  Everyone knew it could happen. that sooner or later it would happen, the skills and knowledge was there, but nothing was done. As for as asteroids go the killer could happen tomorrow or in a thousand years time.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: kevin-rf on 02/16/2013 12:07 AM

I've been digging around in earthquake.usgs.gov and find that the event produced seismic signals as far away as Iowa, perhaps not surprisingly.  There was also a fairly widespread signal about ten minutes before the initial one from Chelyabinsk that was detected strongly in New Zealand, Australia, Hawaii and McMurdo Sound. I suspect this was a coincidentally timed earthquake, but mention it FWIW>


I am out of my depth here, but I vaguely recall from earth science class that earthquakes generate two types of waves that travel at different speeds.  S and P I think. My point being that makes sense that one wave, the P(?) would arrive before the S wave.

Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: AJW on 02/16/2013 12:11 AM
Reports that the flash from meteor attracted attention to the event and as a result, many witnesses were watching the contrail through windows.  The shock wave then hit causing the windows to blow in causing the large number of injuries from glass fragments.

About 15 years ago there was a nighttime KSC shuttle landing and the de-orbit was over California.  My son and I watched the plasma glow stretch across the horizon and as the glow began to fade I carried him back inside to bed.  As we passed a closet, the door shook with sudden ferocity. My assumption was that this was the shock wave from the shuttle, but this was a single shake, not the twin booms reported at the landing sites.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: ChileVerde on 02/16/2013 12:19 AM

I am out of my depth here, but I vaguely recall from earth science class that earthquakes generate two types of waves that travel at different speeds.  S and P I think. My point being that makes sense that one wave, the P(?) would arrive before the S wave.

Yes, compression waves, shear waves and a rich variety of other kinds of waves of lesser importance. (Tensor waves!) Wikipedia has an OK summary.

While we're on this, looking at the collection of seismograms, I think I see a little blip on many of them at 03:13 - 03:16 UTC, the time of the Chelyabinsk entry.  If that's real and connected with the entry, I have no idea what might have caused it.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Blackstar on 02/16/2013 12:22 AM
There's also never (during the space age) been such a pertinent, documented case of why it is important, and probably has never been such public attention to the topic, either.

Gazing into the crystal ball, I can see Congress throwing some more money at the search effort. When we did our NEO study a few years ago the committee generally believed that the amount of money spent on doing the surveys should be increased a bit. Because NASA was then spending $4.5 million on the subject, "a bit" could be increasing it to $10 million annually.

But here's some of the issues:

-in order to substantially improve the surveys for these objects you have to spend A LOT more money. Essentially, you have to build a space-based telescope. No matter what B612 says, that's a half billion dollar investment.

-compare the costs, and the risks, to other events that kill lots of people. If you go back only one decade I bet that you can easily determine that over 800,000 people worldwide were killed by seismic events (250,000 in Haiti alone). Earthquakes represent real dangers to human life.

-where should that $500+ million be spent for maximum effect? Should it be spent on things like asteroids, which are very rare, or should it be spent on things that are much more common?

But I'd hate to see a knee-jerk political reaction to throw cash at this without carefully balancing the issues.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Antares on 02/16/2013 12:43 AM
FWIW, re: Cuba hypothesis, I used a great circle calculator for Chelyabinsk to Havana.  The course is 250.17, which is similar to the course of the meteor trail captured on satellite images.  I think we'd need more data to increase confidence that the rocks came from the same meteor source.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: ChileVerde on 02/16/2013 12:55 AM

-compare the costs, and the risks, to other events that kill lots of people. If you go back only one decade I bet that you can easily determine that over 800,000 people worldwide were killed by seismic events (250,000 in Haiti alone). Earthquakes represent real dangers to human life.

-where should that $500+ million be spent for maximum effect? Should it be spent on things like asteroids, which are very rare, or should it be spent on things that are much more common?

Well, yes, but the question of what 0.5 $G buys in either case arises.

I.e., suppose that amount of money buys a pretty complete assessment of asteroid risk that can be followed up with more $$ on prevention/ mitigation.

You then have to figure out how the same amount of money can be spent on earthquake risk assessment and prevention/mitigation.

In the case of earthquakes, we probably aren't going to prevent them any time soon, so does the 0.5 $G go into earthquake resistant construction in Haiti, Iran and other quaky places? And how much of the population gets protected for that amount of money?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Lee Jay on 02/16/2013 01:01 AM
-in order to substantially improve the surveys for these objects you have to spend A LOT more money. Essentially, you have to build a space-based telescope. No matter what B612 says, that's a half billion dollar investment.

Could Kepler be re-purposed for this sort of work after it's primary mission is complete?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Blackstar on 02/16/2013 01:29 AM
Well, yes, but the question of what 0.5 $G buys in either case arises.

I.e., suppose that amount of money buys a pretty complete assessment of asteroid risk that can be followed up with more $$ on prevention/ mitigation.

You then have to figure out how the same amount of money can be spent on earthquake risk assessment and prevention/mitigation.

In the case of earthquakes, we probably aren't going to prevent them any time soon, so does the 0.5 $G go into earthquake resistant construction in Haiti, Iran and other quaky places? And how much of the population gets protected for that amount of money?

It's not an easy calculation to make. But with space programs, the costs are immense compared to other things. It's easy to say "we should do this space thing" but forget that the money could have better value somewhere else.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 02/16/2013 01:57 AM
Well, yes, but the question of what 0.5 $G buys in either case arises.

I.e., suppose that amount of money buys a pretty complete assessment of asteroid risk that can be followed up with more $$ on prevention/ mitigation.

You then have to figure out how the same amount of money can be spent on earthquake risk assessment and prevention/mitigation.

In the case of earthquakes, we probably aren't going to prevent them any time soon, so does the 0.5 $G go into earthquake resistant construction in Haiti, Iran and other quaky places? And how much of the population gets protected for that amount of money?

It's not an easy calculation to make. But with space programs, the costs are immense compared to other things. It's easy to say "we should do this space thing" but forget that the money could have better value somewhere else.
And yet, we don't do it JUST because of an actuarial cost-benefit analysis. Very little of what NASA does would qualify, maybe some of the stuff in aeronautics.

And again, there is an existential aspect of it that isn't captured in an actuarial perspective and it's one that doesn't really apply to earthquake prediction, etc.

How much have we spent on Hubble? And Hubble doesn't really have an existential purpose. Half a billion for studying NEOs (and other targets, for sure) isn't unreasonable. Which isn't to say we /shouldn't/ be studying how to predict earthquakes, etc. Your arguments seem to work just as well against any kind of space project.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Blackstar on 02/16/2013 02:03 AM
And yet, we don't do it JUST because of an actuarial cost-benefit analysis. Very little of what NASA does would qualify, maybe some of the stuff in aeronautics.

Right. So what?

If the result of this incident in Russia is to throw huge amounts of money at something, supposedly to protect human life, when that money could be much better spent on things that will have a real impact on protecting human life, then that would be a waste.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 02/16/2013 02:13 AM
And yet, we don't do it JUST because of an actuarial cost-benefit analysis. Very little of what NASA does would qualify, maybe some of the stuff in aeronautics.

Right. So what?

If the result of this incident in Russia is to throw huge amounts of money at something, supposedly to protect human life, when that money could be much better spent on things that will have a real impact on protecting human life, then that would be a waste.
Not from my perspective, since I think the level of funding for NASA is already much too low for what we can afford. The real, present danger of the Russian event serves as an illustration for the broader reasons as to why having a robust space program is a good idea. Having a robust space program means you will find (and thus be able to contemplate addressing) threats you perhaps didn't even know existed, as well as future opportunities that otherwise either no one would consider or which wouldn't be possible without the knowledge gained. (And yeah, part of that robustness ought to be reform in NASA, not just throwing cash at the problem.)

And realistically, people aren't going to be throwing cash at NASA. But this event may help prevent a big (maybe even disproportionate) cut in NASA by raising the public's interest in space. People are interested in things which can benefit them but especially things which can harm them (in ways they can't normally control).
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Nittany Lion on 02/16/2013 02:43 AM
Not from my perspective, since I think the level of funding for NASA is already much too low for what we can afford.

And yet, we don't do it JUST because of an actuarial cost-benefit analysis. Very little of what NASA does would qualify, maybe some of the stuff in aeronautics.


Which criteria do you use when you make your own spending decisions? Assuming you are an average American you can afford say 15 cars, if that’s all you bought.

But you probably decided to buy a house, two cars, some food, some clothing, and some etcetera.

An economist would say you equate marginal-utility-to-price ratios over all your purchases. A non-economist would say you maximize the bang for your bucks.

Governmental spending should be allocated similarly and probably is. That makes everyone unhappy because almost no one has tastes that are the same as the _average_ citizen.

Nevertheless the above process maximizes the welfare of society as a whole. I can provide references to the Math behind that statement if you have trouble sleeping.

Now whether government spending in relation to government revenue makes sense is a whole ‘nother story.


Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: sanman on 02/16/2013 03:03 AM
Pleasant mainly, with a small chance of rocks.

Btw, this one is the most dramatic, imho:

http://www.youtube.com/watch?v=b0cRHsApzt8


What are those secondary explosions happening afterwards? Just echoes, maybe? Or did any fragments actually hit the ground, causing damage there?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: yg1968 on 02/16/2013 03:15 AM
Here is another article on the upcoming House hearing on meteor strikes:
http://www.politico.com/story/2013/02/lawmakers-space-asteroids-87723.html?hp=l13
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: yg1968 on 02/16/2013 03:17 AM
Anybody seriously interested in the issue of searching for asteroids and what to do about deflecting them from hitting Earth can check out this study from 2010:

http://www.nap.edu/catalog.php?record_id=12842

Free download.

Thanks.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: sanman on 02/16/2013 03:18 AM

http://www.cnn.com/2013/02/15/world/europe/russia-meteor-shower/index.html

Quote
Deep Space Industries, a recently created space exploration company, said countries should be proactive in establishing "a sentry line of spacecraft circling the Earth to intercept and evaluate incoming threats."

"The hundreds of people injured in northern Russia show it's time to take action and no longer be passive about these threats," said Rick Tumlinson, chairman of Deep Space Industries.

Deep Space Industries - When Big Rocks Terrorize Cities, WE'LL BE THERE! When reporters scurry for soundbites, WE'LL BE THERE!

Hey, so how much platinum did the Earth just gain with this?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: JimO on 02/16/2013 05:00 AM
Here's my CNBC hit from earlier today:
http://www.cnbc.com/id/15840232/?video=3000148418&play=1


Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: sdsds on 02/16/2013 05:02 AM
Speaking of hyperbole....

Vladimir Zhirinovsky is characterized as a "firebrand", "known for clownish political outrage" and being a "perennial provocateur who is no stranger to controversy." Nonetheless he is leader of the Liberal Democratic Party of Russia (LDPR / ЛДПР), and in the 2012 presidential election he received 6.22% of the popular vote.

He asserts this event was not caused by a meteor, but by the United States testing a new weapon.
http://rt.com/politics/zhirinovsky-meteorite-american-weapon-316/
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: sanman on 02/16/2013 05:56 AM
I'm curious - were any aircraft in the air in the vicinity of Chelyabinsk at the time? What would they have experienced?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: russianhalo117 on 02/16/2013 06:45 AM
Revised data valid as of 1900 PST Local Time via NASA JPL


Update: February 15, 2013 7pm PST

New information provided by a worldwide network of sensors has allowed scientists to refine their estimates for the size of the object that entered that atmosphere and disintegrated in the skies over Chelyabinsk, Russia, at 7:20:26 p.m. PST, or 10:20:26 p.m. EST on Feb. 14 (3:20:26 UTC on Feb. 15).

The estimated size of the object, prior to entering Earth's atmosphere, has been revised upward from 49 feet (15 meters) to 55 feet (17 meters), and its estimated mass has increased from 7,000 to 10,000 tons. Also, the estimate for energy released during the event has increased by 30 kilotons to nearly 500 kilotons of energy released. These new estimates were generated using new data that had been collected by five additional infrasound stations located around the world – the first recording of the event being in Alaska, over 6,500 kilometers away from Chelyabinsk. The infrasound data indicates that the event, from atmospheric entry to the meteor's airborne disintegration took 32.5 seconds. The calculations using the infrasound data were performed by Peter Brown at the University of Western Ontario, Canada.

"We would expect an event of this magnitude to occur once every 100 years on average," said Paul Chodas of NASA's Near-Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, Calif. "When you have a fireball of this size we would expect a large number of meteorites to reach the surface and in this case there were probably some large ones."

The trajectory of the Russia meteor was significantly different than the trajectory of the asteroid 2012 DA14, which hours later made its flyby of Earth, making it a completely unrelated object. The Russia meteor is the largest reported since 1908, when a meteor hit Tunguska, Siberia.

----
Previous Data

Preliminary information indicates that a meteor in Chelyabinsk, Russia, is not related to asteroid 2012 DA14, which is flying by Earth safely today.

The Russia meteor is the largest reported since 1908, when a meteor hit Tunguska, Siberia. The meteor entered the atmosphere at about 40,000 mph (18 kilometers per second). The impact time was 7:20:26 p.m. PST, or 10:20:26 p.m. EST on Feb. 14 (3:20:26 UTC on Feb. 15), and the energy released by the impact was in the hundreds of kilotons.

Based on the duration of the event, it was a very shallow entry. It was larger than the meteor over Indonesia on Oct. 8, 2009. Measurements are still coming in, and a more precise measure of the energy may be available later. The size of the object before hitting the atmosphere was about 49 feet (15 meters) and had a mass of about 7,000 tons.

The meteor, which was about one-third the diameter of asteroid 2012 DA14, was brighter than the sun. Its trail was visible for about 30 seconds, so it was a grazing impact through the atmosphere.

It is important to note that this estimate is preliminary, and may be revised as more data is obtained.

http://www.nasa.gov/topics/solarsystem/features/asteroidflyby.html (http://www.nasa.gov/topics/solarsystem/features/asteroidflyby.html)

 
DC Agle 818-393-9011
Jet Propulsion Laboratory, Pasadena, Calif.
agle@jpl.nasa.gov

2013-061
 
LINK containing latest upward revision: http://www.nasa.gov/mission_pages/asteroids/news/asteroid20130215.html (http://www.nasa.gov/mission_pages/asteroids/news/asteroid20130215.html)
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: bubbagret on 02/16/2013 07:20 AM
That would almost fit thru the door on Chamber A at JSC...

http://www.nasa.gov/mission_pages/webb/news/chamber-a.html
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: hektor on 02/16/2013 10:28 AM
Seems to me to belong (dia. 55 ft) to the class of object that could have been detected prior to impact. Wonder what would have been the consequences if it indeed had been detected?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: FinalFrontier on 02/16/2013 10:47 AM
Let the hearings begin!

http://thehill.com/blogs/blog-briefing-room/news/283427-house-committee-to-hold-hearing-on-asteroids-that-pose-a-potential-threat-to-earth (http://thehill.com/blogs/blog-briefing-room/news/283427-house-committee-to-hold-hearing-on-asteroids-that-pose-a-potential-threat-to-earth)

Ah! More funding for SLS! And hopefully an agency wide raise.

Good.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: FinalFrontier on 02/16/2013 10:50 AM
Also this since I was not on earlier:

http://www.youtube.com/watch?v=6_oWCQLyt3Q
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: InvalidAttitude on 02/16/2013 10:52 AM

The estimated size of the object, prior to entering Earth's atmosphere, has been revised upward from 49 feet (15 meters) to 55 feet (17 meters), and its estimated mass has increased from 7,000 to 10,000 tons.

Tons or kilograms?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: hektor on 02/16/2013 10:54 AM
Metric tons. Ten thousand metric tons.

http://www.nasa.gov/mission_pages/asteroids/news/asteroid20130215.html
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: FinalFrontier on 02/16/2013 11:04 AM
Metric tons. Ten thousand metric tons.

http://www.nasa.gov/mission_pages/asteroids/news/asteroid20130215.html


"Estimated energy released has been revised to 500 kilotons"

Yep that’s about the same as any of the W60 on up warheads we use on most of our missiles.

It is fortunate it did not explode closer to the ground.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: hektor on 02/16/2013 11:11 AM
I guess it will be an interesting case study in the future. Explosion of 500 kt at altitude 30 km above a large city.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: psloss on 02/16/2013 11:24 AM
Let the hearings begin!

http://thehill.com/blogs/blog-briefing-room/news/283427-house-committee-to-hold-hearing-on-asteroids-that-pose-a-potential-threat-to-earth (http://thehill.com/blogs/blog-briefing-room/news/283427-house-committee-to-hold-hearing-on-asteroids-that-pose-a-potential-threat-to-earth)

Ah! More funding for SLS! And hopefully an agency wide raise.

Good.
No, the hearing is just public discovery/disclosure (and the other things that come with hearings).  It might extend the visibility of the event, but increased federal funding is far from a certainty, especially on a large scale.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: smoliarm on 02/16/2013 11:27 AM
... looking at the collection of seismograms...
Is there any chance to tell from heliplot if we are looking at shock wave hitting the ground or at impact of massive solid body? (Theoretically, there should be difference in shape/magnitude, but I have no personal experience here).
Or, in other words - could you tell by heliplot data that there was a large (on a tonne scale) body hitting the ground with supersonic speed? Or, do these plots give evidence that there was NO such event?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: R7 on 02/16/2013 11:45 AM
I guess it will be an interesting case study in the future. Explosion of 500 kt at altitude 30 km above a large city.

Even if yields are the same effects of nuke would be quite different, no? Meteor dissipates it's energy during several seconds to path of several tens(?) of kilometers. Nuke releases it all in microseconds to one point. Wildly different shockwave ensues.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: yg1968 on 02/16/2013 12:23 PM
There's also never (during the space age) been such a pertinent, documented case of why it is important, and probably has never been such public attention to the topic, either.

Gazing into the crystal ball, I can see Congress throwing some more money at the search effort. When we did our NEO study a few years ago the committee generally believed that the amount of money spent on doing the surveys should be increased a bit. Because NASA was then spending $4.5 million on the subject, "a bit" could be increasing it to $10 million annually.

But here's some of the issues:

-in order to substantially improve the surveys for these objects you have to spend A LOT more money. Essentially, you have to build a space-based telescope. No matter what B612 says, that's a half billion dollar investment.

-compare the costs, and the risks, to other events that kill lots of people. If you go back only one decade I bet that you can easily determine that over 800,000 people worldwide were killed by seismic events (250,000 in Haiti alone). Earthquakes represent real dangers to human life.

-where should that $500+ million be spent for maximum effect? Should it be spent on things like asteroids, which are very rare, or should it be spent on things that are much more common?

But I'd hate to see a knee-jerk political reaction to throw cash at this without carefully balancing the issues.

If the cost is $500M, it would seem reasonable considering that NASA has a $17B per year budget. This is the kind of work that NASA is expected to do. If NASA doesn't do this kind of work, taxpayers will eventually question whether their $17B per year "investment" into NASA is put to good use.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: ChileVerde on 02/16/2013 01:35 PM
... looking at the collection of seismograms...
Is there any chance to tell from heliplot if we are looking at shock wave hitting the ground or at impact of massive solid body? (Theoretically, there should be difference in shape/magnitude, but I have no personal experience here).

Or, in other words - could you tell by heliplot data that there was a large (on a tonne scale) body hitting the ground with supersonic speed? Or, do these plots give evidence that there was NO such event?

I would think so, but don't really know either. Hopefully people who have expertise in such matters will publish on the event in due course.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: FinalFrontier on 02/16/2013 01:52 PM
Let the hearings begin!

http://thehill.com/blogs/blog-briefing-room/news/283427-house-committee-to-hold-hearing-on-asteroids-that-pose-a-potential-threat-to-earth (http://thehill.com/blogs/blog-briefing-room/news/283427-house-committee-to-hold-hearing-on-asteroids-that-pose-a-potential-threat-to-earth)

Ah! More funding for SLS! And hopefully an agency wide raise.

Good.
No, the hearing is just public discovery/disclosure (and the other things that come with hearings).  It might extend the visibility of the event, but increased federal funding is far from a certainty, especially on a large scale.


I meant metaphorically of course.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Blackstar on 02/16/2013 01:58 PM
If the cost is $500M, it would seem reasonable considering that NASA has a $17B per year budget. This is the kind of work that NASA is expected to do. If NASA doesn't do this kind of work, taxpayers will eventually question whether their $17B per year "investment" into NASA is put to good use.

Here is what has happened in the past:

A few members of Congress (Rohrabacher is one) have inserted language into NASA authorization bills (not appropriations bills) requiring the agency to detect potentially hazardous NEOs. Because of the way that Congress works, where the leadership often has to give out trinkets to the members in order to get things passed, this language has survived into authorization acts even though the vast majority of members don't care about the subject or even know anything about it. (Note: this happens all the time for lots and lots of things, not just searching for asteroids.)

This requirement landed on NASA, but did not come with any new money appropriated for that purpose. Now what the authorizing committee hoped would happen is that the administration (White House/President) would submit a budget proposal that included sufficient money to accomplish the task. But the administrations (Clinton, then Bush, then Obama) didn't care about the issue. So they did not ask for additional money to do it, they simply redirected money from inside NASA to do it partway. The result is that the money has gotten cut out of other things at NASA, and the agency has never really had the resources to accomplish it.

This is just a variation of the common situation of the "unfunded mandate."

What people within NASA have worried about for years is that Congress would increase the unfunded mandate, essentially directing that more of the agency's current budget be allocated for doing this thing. That would force them to cut the money from something else. But what? It's common for the advocates to say "take it from the science budget because asteroids are science." But counting rocks is not a scientific pursuit. And this is a terrestrial defense project, so why should that money come out of the science budget? Shouldn't the Department of Homeland Security or the DoD pay for it? And officially the administration has set a goal of sending humans to an asteroid, and so shouldn't the human spaceflight program spend the money searching for asteroids?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mlindner on 02/16/2013 02:22 PM
Anyone who knows russian. What are they saying in this video with regards to the impact crater?

http://www.youtube.com/watch?v=VNLG4YtM5NM
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: RichardAKJ on 02/16/2013 02:41 PM
If the cost is $500M, it would seem reasonable considering that NASA has a $17B per year budget. This is the kind of work that NASA is expected to do. If NASA doesn't do this kind of work, taxpayers will eventually question whether their $17B per year "investment" into NASA is put to good use.

Here is what has happened in the past:

A few members of Congress (Rohrabacher is one) have inserted language into NASA authorization bills (not appropriations bills) requiring the agency to detect potentially hazardous NEOs. Because of the way that Congress works, where the leadership often has to give out trinkets to the members in order to get things passed, this language has survived into authorization acts even though the vast majority of members don't care about the subject or even know anything about it. (Note: this happens all the time for lots and lots of things, not just searching for asteroids.)

This requirement landed on NASA, but did not come with any new money appropriated for that purpose. Now what the authorizing committee hoped would happen is that the administration (White House/President) would submit a budget proposal that included sufficient money to accomplish the task. But the administrations (Clinton, then Bush, then Obama) didn't care about the issue. So they did not ask for additional money to do it, they simply redirected money from inside NASA to do it partway. The result is that the money has gotten cut out of other things at NASA, and the agency has never really had the resources to accomplish it.

This is just a variation of the common situation of the "unfunded mandate."

What people within NASA have worried about for years is that Congress would increase the unfunded mandate, essentially directing that more of the agency's current budget be allocated for doing this thing. That would force them to cut the money from something else. But what? It's common for the advocates to say "take it from the science budget because asteroids are science." But counting rocks is not a scientific pursuit. And this is a terrestrial defense project, so why should that money come out of the science budget? Shouldn't the Department of Homeland Security or the DoD pay for it? And officially the administration has set a goal of sending humans to an asteroid, and so shouldn't the human spaceflight program spend the money searching for asteroids?

In your opinion, is this likely to change given the close pass and Russian impact?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Archibald on 02/16/2013 03:01 PM
I think we'd need more data to increase confidence that the rocks came from the same meteor source.

Klendathu?

I, For One, Welcome Our New Arachnid Overlords !
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: psloss on 02/16/2013 03:08 PM
If the cost is $500M, it would seem reasonable considering that NASA has a $17B per year budget. This is the kind of work that NASA is expected to do. If NASA doesn't do this kind of work, taxpayers will eventually question whether their $17B per year "investment" into NASA is put to good use.
Those kinds of things -- examining and questioning U.S. federal space policy -- happen in small circles like this forum; most taxpayers don't spend more than a few web clicks worth of time on space policy.

If this event had been local to the U.S., I would agree with others here speculating possible motivation to act; however, as it relates to the U.S., this is more along the lines of the Indian Ocean tsunami back at the very end of 2004.  (Or the Haitian earthquake already mentioned.)
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Artyom. on 02/16/2013 03:09 PM
Anyone who knows russian. What are they saying in this video with regards to the impact crater?

http://www.youtube.com/watch?v=VNLG4YtM5NM

Sorry if I'm not clear translated  ::), but nothing new... It supposedly fell one out of the wreckage. Crater from a meteorite collision with Earth is at least 10 meters. Police officers yet don't give official comments. According to regional GUVD (City Police Department) there it is collected examples of black, strong substance which are sent for examination. Background radiation is normal :) !
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: JohnFornaro on 02/16/2013 03:19 PM
-compare the costs, and the risks, to other events that kill lots of people. ... Earthquakes represent real dangers to human life.

-where should that $500+ million be spent for maximum effect? Should it be spent on things like asteroids, which are very rare, or should it be spent on things that are much more common?

Well, yes, but the question of what 0.5 $G buys in either case arises.

I.e., suppose that amount of money buys a pretty complete assessment of asteroid risk that can be followed up with more $$ on prevention/ mitigation.

You then have to figure out how the same amount of money can be spent on earthquake risk assessment and prevention/mitigation.

In the case of earthquakes, we probably aren't going to prevent them any time soon, so does the 0.5 $G go into earthquake resistant construction in Haiti, Iran and other quaky places? And how much of the population gets protected for that amount of money?

First, you have no grounds to make the supposition that $500M "buys a pretty complete assessment of asteroid risk".

In addition, since neither large quakes nor large asteroid strikes can be prevented, the other factor that could be "bought" would be prediction.

With respect to a quake in a coastal area, several days of prediction could result in an orderly evacuation, with no real ensuing panic.

In the case of an asteroid, one would have to predict the city which would be hit.  Hard to imagine that evacuation taking place without panic.  Hence, hard to imagine the city being predicted publicly by name.  If the prediction were six months in advance, hard to imagine an evacuation, tho the panic might be reduced.

So I think part of what RobotBeat suggests is spot on:

And yet, we don't do it [space programs in general] JUST because of an actuarial cost-benefit analysis. Very little of what NASA does would qualify, maybe some of the stuff in aeronautics.

And again, there is an existential aspect of it that isn't captured in an actuarial perspective and it's one that doesn't really apply to earthquake prediction, etc.

How much have we spent on Hubble? And Hubble doesn't really have an existential purpose. Half a billion for studying NEOs (and other targets, for sure) isn't unreasonable. Which isn't to say we /shouldn't/ be studying how to predict earthquakes, etc. Your arguments seem to work just as well against any kind of space project.

His is a less confrontational way of saying that fundamentally, mankind doesn't have an "actuarial" need for space programs such as Hubble.  The ability to predict an asteroid strike would have an actuarial value, but it would certainly have to be compared against competing needs with higher value and better chances of accurate prediction.

An economist would say you equate marginal-utility-to-price ratios over all your purchases. A non-economist would say you maximize the bang for your bucks.

Governmental spending should be allocated similarly and probably is.

What's the weather like on your planet?

... Snarky comments aside, our government works quite nicely on the whole. As evidence I’ll cite that one of our greatest problems is the number of people who want to come here, greatly in excess of what our immigration laws allow.

Thing is, QG's right in snarking your naive economist.  "Marginal utility to price ratios" might apply in big business to some extent, but not really to ordinary Janes.  A trip to the refrigerator upstairs illustrates the point:

There is no economic theory which can even begin to model the economic difference between "ChaChing Cherry", "Art Dealer Teal-er", "Mango Mango 400", "260 Sonic Boom", "B426 Trevi Gold F", or any of the three dozen economic products on that refrigerator shelf.  And these are only the tiniest subset of the economic decisions out there to be made in the private sector.

Worse, while our government might be the best on the planet, it doesn't work "quite nicely on the whole", particularly when assesing "marginal utility to price ratios".
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Ben the Space Brit on 02/16/2013 03:23 PM
From the data I've seen, the Chelyabinsk Object was in a high-inclination Earth-grazing orbit.  Additionally, as it's trajectory seems to have been from the direction of the Sun, it might have also been in a high-eccentricity orbit.  In other words, it might have normally been closer to the Sun than the Earth and either off the ecliptic or optically close to the Sun in the sky.  I think that would have worked strongly against it being detected before.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: sanman on 02/16/2013 03:53 PM
What if this thing had not been in an Earth-grazing trajectory, but had instead hit full-on, in surface-normal trajectory? Would it have smashed into the ground rather than exploding overhead?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Mongo62 on 02/16/2013 04:00 PM
From the science blog Dynamics of Cats (http://"http://scienceblogs.com/catdynamics/2013/02/16/impacts/"):

Quote
Air has density of about 10^-3, at ground level decreasing approximately exponentially with scale height, and the scale height is of order 10 km. Therefore meteors tend to break up at 10-20 km altitude if they don’t make it to the ground. A 1 m rock needs to sweep a path of over 2 km through the air to stop effectively, a 12 m rock needs about 24 km of air to stop. So a rock that big coming straight down will likely hit the ground.

The Chelyabinsk meteor came in at a shallow angle, and so traversed a column of air long enough to brake it and break it. This is very fortunate, or we’d have had a ground detonation of a few hundred kilotons and likely mass casualties.

Most of the injuries seem to have been from broken glass, consistent with reports of other large explosions.

Glass breaks from overpressure of about 1/4 PSI – and as the bomb damage calculator (below) shows, that overpressure goes out to about 20 km radius (for ground detonations which this was not). Here we had an air detonation (worse) but with the energy spread out over a linear track, not deposited instantaneously at a point (both better and worse).

Hence the damage was consistent along the track and for tens of km either side of it, but nowhere was there a point or line of extreme destruction. A little bit higher energy impact, steeper impact angle, faster speed or bigger rock, and there would have been a zone of severe damage surrounded by an elongated annulus of the moderate damage actually seen, and there would have been many deaths.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: R7 on 02/16/2013 04:01 PM
What if this thing had not been in an Earth-grazing trajectory, but had instead hit full-on, in surface-normal trajectory? Would it have smashed into the ground rather than exploding overhead?

See

http://forum.nasaspaceflight.com/index.php?topic=31118.msg1013385#msg1013385 (http://forum.nasaspaceflight.com/index.php?topic=31118.msg1013385#msg1013385)
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Archibald on 02/16/2013 04:39 PM
Incidentally the reason why a lot of Russian news report insists heavily on "low radiation levels",   is because that unfortunate region also suffered some huge nuclear disaster back in 1957.
http://en.wikipedia.org/wiki/Kyshtym_disaster
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: LegendCJS on 02/16/2013 05:31 PM
There's also never (during the space age) been such a pertinent, documented case of why it is important, and probably has never been such public attention to the topic, either.

Gazing into the crystal ball, I can see Congress throwing some more money at the search effort. When we did our NEO study a few years ago the committee generally believed that the amount of money spent on doing the surveys should be increased a bit. Because NASA was then spending $4.5 million on the subject, "a bit" could be increasing it to $10 million annually.

But here's some of the issues:

-in order to substantially improve the surveys for these objects you have to spend A LOT more money. Essentially, you have to build a space-based telescope. No matter what B612 says, that's a half billion dollar investment.

-compare the costs, and the risks, to other events that kill lots of people. If you go back only one decade I bet that you can easily determine that over 800,000 people worldwide were killed by seismic events (250,000 in Haiti alone). Earthquakes represent real dangers to human life.

-where should that $500+ million be spent for maximum effect? Should it be spent on things like asteroids, which are very rare, or should it be spent on things that are much more common?

But I'd hate to see a knee-jerk political reaction to throw cash at this without carefully balancing the issues.

There is an exciting body of evidence showing that large earthquakes are preceded by magnetic disturbances due to large underground current flow form piezo electric effects.  Studies have spotted these signatures by their effect on GPS signals.  I can imagine that a large pot of money could be used to make a monitoring system that would provide warning to regions showing similar signatures.  Smaller earthquakes, which are harder to detect, do not cause as much damage (unless you have crap enforcement of construction standards).

The actions to take in response to a warning would be pre-positioning emergency goods, prep-work like reinforcements, window coverings (kind of like hurricane), clearing of evacuation routes and fire hazards, removing stuff form precarious high shelves... up to possible evacuations.

There have been periods of recent history when the Chelyabinsk even would have sparked WWIII, and there are some locations on this planet where it might have sparked regional conflicts even today.

Both spending for better NEO detection and spending for Earthquake detection is spending on research, I don't see the problem with it, even if it is knee-jerk based decisions that make it happen.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: sanman on 02/16/2013 06:32 PM
Or you could just buy a canary - if it suddenly starts squawking, then you have 15 secs to duck and cover.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: R7 on 02/16/2013 07:03 PM
Couple weeks from now and nobody remembers Chelyabinsk. Public and media attention span is short. News are already stressing how unlikely the event was. No $500M to prevent mass window-breaking event once every one hundred years.  :-[

Would love to be wrong on this one though.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Apollo-phill on 02/16/2013 07:17 PM
I was in Iceland on Monday 11 Feb 2013 watching the Northern lights - an incredible spectacle lasting over 3 hours.

While watching saw four meteors streak across night sky - at separate times - moving from north to northeast . Related to this mini asteroid?

Phill

Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: JimO on 02/16/2013 07:26 PM
I'm scheduled for a hit on NBC Nightly tonight, with mitigation justifications....
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: sanman on 02/16/2013 07:29 PM
Here's a cute little interview with NASA astrophysicist Neil DeGrasse Tyson, where he also talks about mitigation:

http://www.youtube.com/watch?v=NTXna-Igf4I

Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: DaveS on 02/16/2013 07:30 PM
I was in Iceland on Monday 11 Feb 2013 watching the Northern lights - an incredible spectacle lasting over 3 hours.

While watching saw four meteors streak across night sky - at separate times - moving from north to northeast . Related to this mini asteroid?

Phill


Don't think so. Remember, the Earth is constantly bombarded with stuff like really small MMOD. If I remember yesterday's teleconference right, I think the number mentioned was something like 800 metric tonnes per day of space stuff.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Danderman on 02/16/2013 07:34 PM
Suspected meteor explosion reported in central Cuba

http://www.globaltimes.cn/content/761637.shtml

An object fell from the sky over central Cuba on Thursday night and turned into a fireball "bigger than the sun" before it exploded, a Cuban TV channel reported Friday, citing eyewitnesses.

Some residents in the central province of Cienfuegos were quoted as saying that at around 8 p.m. local time Thursday (0100 GMT Friday) they saw a bright spot in the sky comparable to a bus in size.

The object then turned into a fireball "bigger than the sun," said the witnesses, adding that several minutes later they heard a loud explosion.

One resident told the TV station that his house shook slightly in the blast.

Cuban experts have been dispatched to the area to look for possible remains of the meteor-like object, said the report.

It remains unknown whether the reported phenomenon in Cuba is related to Friday's meteor strike in central Russia, which set off a shockwave that shattered windows and left some 1,000 people injured.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Ben the Space Brit on 02/16/2013 08:24 PM
Couple weeks from now and nobody remembers Chelyabinsk. Public and media attention span is short. News are already stressing how unlikely the event was. No $500M to prevent mass window-breaking event once every one hundred years.  :-[

Would love to be wrong on this one though.

Heck, the media here in the UK is already folding up its tents and going home.  The story is vanishing from web front pages, is no longer mentioned on TV news and didn't make the front page of any British paper, even the "quality" press.

As cynical as this sounds, a part of me wonders if they would have taken it more seriously if it had been a mass-fatality event or would it still have been "something that happens in foreign lands that are of no interest to our readers/viewers" and quickly forgotten.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: lcs on 02/16/2013 08:30 PM
Suspected meteor explosion reported in central Cuba

http://www.globaltimes.cn/content/761637.shtml

An object fell from the sky over central Cuba on Thursday night and turned into a fireball "bigger than the sun" before it exploded, a Cuban TV channel reported Friday, citing eyewitnesses.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: sanman on 02/16/2013 08:40 PM
This is obviously a result of Global Warming (so says CNN anchor):

http://www.youtube.com/watch?v=E-QA-jlbRqY

I guess that's why they call it Meteorology!   :P
Bang! Zoom! To da Moon, Alice!
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: R7 on 02/16/2013 08:55 PM
This is obviously a result of Global Warming (so says CNN anchor):
I guess that's why they call it Meteorology!   :P
Bang! Zoom! To da Moon, Alice!

;D

http://www.youtube.com/watch?v=bcYppAs6ZdI (http://www.youtube.com/watch?v=bcYppAs6ZdI)
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: darkenfast on 02/16/2013 09:26 PM
That sounds like a classic example of modern liberal arts education. I thought it was a joke until I actually listened to it.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Mongo62 on 02/16/2013 09:44 PM
Her comment about a link between global warming and asteroids was obviously a joke.

And yes, it is nearly certain that global warming had a LOT to do with Sandy.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: sdsds on 02/16/2013 09:46 PM
Well-reasoned op-ed in the Washington Post by Rush Holt (D - NJ, and former assistant director of the Princeton Plasma Physics Laboratory) and Donna F. Edwards (D - MD, and ranking Democrat on the House subcommittee on space):

http://www.washingtonpost.com/opinions/were-on-notice-to-plan-for-the-next-meteor/2013/02/15/c46b7c1a-77ab-11e2-aa12-e6cf1d31106b_story.html
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: iamlucky13 on 02/16/2013 09:49 PM
Before I start my long catch up post, I've read the later posts, and I agree with Blackstar - whatever intention we state or plan we make is pointless if we don't provide actual appropriations to accomplish it.

We could start by putting this in perspective. How many people have died in the past decade from seismic-related events? How much money is being spent to predict those?

No one knows of a reliable way to predict individual seismic events, just long-term probabilities.

Instead, as you know, we mitigate the effects. The US spends over $800 billion per year on construction projects (Census Bureau (http://www.census.gov/construction/c30/c30index.html)). If even 5% of that (I suspect it's more, but don't have a good source for) is due to the expense of meeting or upgrading to seismic standards, then that means the US alone spends over twice NASA's entire budget addressing earthquakes...

...to mitigate a hazard that has killed two people in the last decade (USGS (http://earthquake.usgs.gov/earthquakes/states/us_deaths.php))

But we do, of course, know of a fairly reliable way to predict asteroid impacts - by cataloging asteroids as thoroughly as possible.

Going from 95% of 1 km and 5% of 140 meter (the current survey status according to Blackstar) to 100% of 15 meter sounds like a colossal effort. Add to that some sort of deflection capability and you’re probably talking $500 billion.

The observed frequency of need is one zero-fatality air burst per century, and one extinction event per 65 million years.

Wouldn’t it be better to spend the money developing the capability to deflect hurricanes and tornadoes? Lotta people gonna think that way.

You don't need a standing deflection capability. You just need to know where they are long enough ahead of time to prepare a single response if one does turn out to be a problem. 99942 Apophos was perfectly illustrative of what we want to achieve. It was discovered in 2004, large enough to potentially cause regional devastation and immediately noted as at risk of a collision 32 years later. We now know it won't hit in 2036, but if it were to, we'd have had 3 decades to figure out what to do about it.

That does leave a short-term risk we find something too late to develop a response other than shelter or evacuate, but the alternative is not finding it until it's too late for even that. I very much agree the cost of a standing deflection capability is not merited by the extremely low short-term risk.

Even so, $500 billion is clearly just an arbitrarily large number you picked. You're implying a project the size of the space shuttle program operating for a century!

Most of the asteroids discovered so far have been found using ~1m automated telescopes - roughly the size of those used to film shuttle launches. The most prolific asteroid-hunting program so far, the Catalina Sky Survey has a budget on the order of $1 million per year (http://azdailysun.com/news/local/state-and-regional/small-scopes-reach-beyond-solar-system/article_5d8d062c-fe77-11de-926d-001cc4c002e0.html), and just began a $4 million upgrade (http://www.nbcnews.com/id/46776588/ns/technology_and_science-space/#.UR_v_PK3Z8F), about a decade after the last upgrade.

$1.5 million per year is peanuts. Since you mention hurricanes and tornados - roughly half of NOAA's $5 billion annual budget goes the National Weather Service and the cost maintaining and operating weather satellites.

As is often said, a hit with mass fatalities is not a matter of "if" but a matter of "when." However, the knowledge we gain from this search is nearly permanent. Once an asteroid is discovered, it only needs occasional follow-up observations to refine the long-term orbit predictions. Searching now lays the groundwork for protecting our planet for as long as civilization endures.

Keep in mind, I'm not saying we need any kind of crash program to launch a fleet of Hubble-size asteroid hunters or anything like that.

We're honestly making excellent progress as is, even though I think it's worth trying at least a little harder. What would it cost to double the size of our current ground-based telescopes, thereby quadrupling their sensitivity? I'd be shocked if it even cracked $100 million, but it would further accelerate the discovery rate of medium-to-large asteroids, and enable us to find even smaller asteroids than we otherwise would.

Meanwhile, even with the existing scopes, astronomers are finding other uses for the Catalina data, such as measuring variability in star brightness. For that matter, cataloging asteroids is in its own right scientifically informative as well as consistent with one of the often-discussed exploration roadmaps.

We can't expect to pull off any such amazing feat as cataloging 100% of the near earth asteroids 15m or larger (and even that would still leave long-period comets undetected), but it is feasible and we're well on our way to discovering all the asteroids that can destroy an entire country (1 km+), and we can credibly and reasonably locate given enough time most of the asteroids that can destroy a city or state-sized area (100m-1km).


Part of the reason they went on trial is because they told their citizens not to bother preparing for earthquakes and enjoy a glass of wine. Totally unrelated.

It was an administrator who told people to have a glass of wine. The geologists had briefed him that they had no indications that what turned out to be foreshocks were any different than previous earthquake swarms. The administrator definitely and the geologists probably merited some civil action for downplaying the risk, but a criminal charge of manslaughter is completely out of proportion with what amounted to them saying, "we don't think what's going merits people sleeping in the streets in near freezing weather and at risk of robbery and other crimes" (as the prosecution absurdly claimed those who died would have done to protect themselves if a more appropriate statement had been made like "Small earthquakes like these sometimes precede more serious earthquakes but we have no reliable way of knowing if a larger quake is imminent").

The real issue, which the entire trial exuded a vibe of deliberate distraction from, is the fact that in a city with a long history of mass casualties from earthquakes, the construction quality (even of some of the modern buildings) was poor enough for a relatively moderate M6.3 to kill hundreds of people.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Leo E Liptical on 02/16/2013 10:07 PM
Russian news now reporting no fragments found in lake, maybe due to hole in ice formed because of different reason, not impact.

See rt.com
This is what they posted:
18:40 GMT: The search for the meteorite parts at Chebarkul Lake and at
other two locations has officially been stopped. The huge ice hole
found at the lake on Friday “has formed because of a different reason,”
the Vice-Governor of Chelyabinsk region Igor Murog told Interfax-Ural.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: iamlucky13 on 02/16/2013 10:23 PM
In this video (posted previously), the shock wave arrives at 1:10. After the initial startle, the camera is then pointed at a rising cloud of smoke coming from a source hidden by a building. The smoke appears new.

See also pictures labeled 01, 02, and 03 on this page showing the zinc factory. Photo 1 shows a similar cloud of smoke as the video:
http://zyalt.livejournal.com/722930.html#cutid1

Furthermore, all of the damage I've seen so far has been broken windows, and in the worst cases, a couple doors knocked off hinges. No other structural collapses from the shock wave, but in photo 03, the bricks appear to have been scattered pretty forcefully.

So I additionally am led to speculate the zinc factory was hit by a fragment, although there appears to be no word on that yet, so my only basis is disbelief that this singular building would suffer so much worse damage than everything else.

The timing would be coincidental, but not incredible - no doubt the meteor was still supersonic at the time of breakup, so the fragment would at first outpace the shockwave, then slow below supersonic, with the shockwave just happening to catch up to it again at about the same time it hit the ground.

http://www.youtube.com/watch?feature=player_embedded&v=SRSrdOfbnHI#!
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: QuantumG on 02/16/2013 10:32 PM
Her comment about a link between global warming and asteroids was obviously a joke.

And yes, it is nearly certain that global warming had a LOT to do with Sandy.

The problem was that it was a rain storm.. if it had been a little colder it would have been an ice storm instead. Ice can't hurt people, because it's a crystal and crystals heal people.

Many meteorites also have crystals in them. The Russians were hurt mostly by flying glass.. which is not a crystal. It will be expensive to replace all the glass in the world with crystal but if it saves just one child's life, I think it's worth it.


Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: sanman on 02/16/2013 10:40 PM
I think her comment was more babble or banter than joke, and it still came across as ignorant rather than informed.

Anyway, here's an interesting site to let you sling some stones at Earth:

http://www.purdue.edu/impactearth/
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: bubbagret on 02/16/2013 10:47 PM
Q.G. for the win!
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: iamlucky13 on 02/16/2013 10:50 PM
What if this thing had not been in an Earth-grazing trajectory, but had instead hit full-on, in surface-normal trajectory? Would it have smashed into the ground rather than exploding overhead?

You can play around with different sample cases at the Asteroid Impact Effects Calculator, easily one of the coolest online widget I've ever come across. According the accompanying white paper, it was created by a couple graduate students and takes into decent estimate methods from multiple academic fields related to the effects it calculates. It will, of course, still be far from perfect, but it's as good of a tool as you will find for making rough predictions:

http://impact.ese.ic.ac.uk/ImpactEffects/

From the best size estimates so far (NASA JPL (http://www.jpl.nasa.gov/news/news.php?release=2013-061)), if I use 17 km/s entry speed and a 30 degree angle, it estimates a 130 kt airburst representing a little under of 1/2 the total kinetic energy at 27km altitude and only fragments reaching the surface. Pretty darn good agreement with what JPL is saying so far.

If I crank the angle up to 90 degrees, it makes it down to 18 km.

Of course, that depends heavily on its composition and coherency. A rubble pile is going to fall apart very quickly. A chunk knocked off a body that was large enough to at one point in the solar system's history be molten and therefore have cooled into a solid rock would make it a lot further down, possibly reaching the ground intact.

A solid enough meteorite most definitely can reach the ground intact, and even survive impact. The Willamette Meteorite, an iron-nickle specimen, is roughly 3m x 2m and weighs 14 tonnes - far smaller.

http://en.wikipedia.org/wiki/Willamette_Meteorite


Even if yields are the same effects of nuke would be quite different, no? Meteor dissipates it's energy during several seconds to path of several tens(?) of kilometers. Nuke releases it all in microseconds to one point. Wildly different shockwave ensues.

A bit different, but air can only transmit the energy from a nuclear blast so fast, and you end up that after traveling a certain distance, the main shockwave can be pretty similar.

Incidentally the reason why a lot of Russian news report insists heavily on "low radiation levels",   is because that unfortunate region also suffered some huge nuclear disaster back in 1957.
http://en.wikipedia.org/wiki/Kyshtym_disaster

Is it because of that, or is it because almost no one in the media understands the difference between radiation exposure (such as in space) and radioactivity, and therefore believes everything in space is radioactive?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: iamlucky13 on 02/16/2013 10:55 PM
Russian news now reporting no fragments found in lake, maybe due to hole in ice formed because of different reason, not impact.

See rt.com
This is what they posted:
18:40 GMT: The search for the meteorite parts at Chebarkul Lake and at
other two locations has officially been stopped. The huge ice hole
found at the lake on Friday “has formed because of a different reason,”
the Vice-Governor of Chelyabinsk region Igor Murog told Interfax-Ural.

The hole was found immediately after the meteor event, in the right area, with bits of dark rock similar to other meteors.

He's jumping to the conclusion that because they can't sort whatever chunks may have survived the impact from all the other rocks on the bottom of a frozen lake that therefore the hole has to have resulted from something else.

In my opinion, the evidence so far points very heavily to that hole in the ice being where a fragment landed. His conclusion is hasty.

Of course, that doesn't mean it's productive to continue searching given the conditions.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: asmi on 02/16/2013 11:00 PM
So the world's reaction to the event can be summed up like this: "Not in our backyard". What saddens me the most that it would take a direct hit with mass casualties until pociticians in power will get their asses up and actually do something about that...
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 02/16/2013 11:04 PM
I'm scheduled for a hit on NBC Nightly tonight, with mitigation justifications....

PLEASE do a good job! Don't do what we normally do and spend the whole time talking about how rare something like this is, trying to get people not to care. You don't have to scare mongering but do a good job selling in general why it is good to have broad capabilities in science and technology so when the time comes we can be ready.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: ugordan on 02/16/2013 11:11 PM
The timing would be coincidental, but not incredible - no doubt the meteor was still supersonic at the time of breakup, so the fragment would at first outpace the shockwave, then slow below supersonic, with the shockwave just happening to catch up to it again at about the same time it hit the ground.

In the beginning I thought it was a fragment, too, but Occam's razor suggests the much simpler explanation of the (old?) roof  collapsing due to overpressure. Keep in mind that the blast was relatively overhead so the shockwave was directed downward and there was probably no significant Mach stem effect. Vertical windows wouldn't experience the same forces a horizontal roof would.

Also technically, a fragment can't outpace a shockwave, it would produce its own shockwave instead - which would have been heard for something big enough to cave in a roof. Yet I don't see how a low ballistic coefficient object could outrun the much more massive main body mass and its shockwave and result in a weaker sonic boom before the main impact - which wasn't heard as far as I can tell, either.

Consider also that the hole in the roof is really big, I would imagine a fragment punching a more localized hole.

Most videos I've seen don't seem to do justice to the sound and power of that shockwave, ironically it's this low quality video that I think captures it best:

http://www.youtube.com/watch?v=b0cRHsApzt8

I have little trouble believing this kind of thing could explain the damage seen at that zinc factory.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: JimO on 02/16/2013 11:49 PM
Feb 16,  2013 3-min piece leads the Nightly News [my wrapup at 2:40]
http://www.nbcnews.com/id/3032619/ns/NBCNightlyNews/

They used only a few direct words from me, but I spent half an hour with the producer and a lot of the narration words are mine, too.

[Feb 15 hit on CNBC: http://www.cnbc.com/id/15840232/?video=3000148418&play=1]
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Rocket Science on 02/16/2013 11:58 PM
Feb 16,  2013 3-min piece leads the Nightly News [my wrapup at 2:40]
http://www.nbcnews.com/id/3032619/ns/NBCNightlyNews/

They used only a few direct words from me, but I spent half an hour with the producer and a lot of the narration words are mine, too.

[Feb 15 hit on CNBC: http://www.cnbc.com/id/15840232/?video=3000148418&play=1]
I liked your phrase: “caught in a cosmic crossfire” easy to visualize... Well done JimO !  :)
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: boaorm on 02/17/2013 12:06 AM
A plausible explanation for the damage at the zink factory is a dust explosion initiated by the shock wave and any ignition source inside.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: smoliarm on 02/17/2013 12:53 AM
In this video (posted previously), the shock wave arrives at 1:10. After the initial startle, the camera is then pointed at a rising cloud of smoke coming from a source hidden by a building. The smoke appears new.

See also pictures labeled 01, 02, and 03 on this page showing the zinc factory. Photo 1 shows a similar cloud of smoke as the video:
http://zyalt.livejournal.com/722930.html#cutid1

Furthermore, all of the damage I've seen so far has been broken windows, and in the worst cases, a couple doors knocked off hinges. No other structural collapses from the shock wave, but in photo 03, the bricks appear to have been scattered pretty forcefully.

So I additionally am led to speculate the zinc factory was hit by a fragment, although there appears to be no word on that yet, so my only basis is disbelief that this singular building would suffer so much worse damage than everything else.

The timing would be coincidental, but not incredible - no doubt the meteor was still supersonic at the time of breakup, so the fragment would at first outpace the shockwave, then slow below supersonic, with the shockwave just happening to catch up to it again at about the same time it hit the ground.

http://www.youtube.com/watch?feature=player_embedded&v=SRSrdOfbnHI#!

>>Photo 1 shows a similar cloud of smoke as the video
There were several fires in the city - all in industrial buildings, and all from heating oil burners damaged by shock wave. Fortunately, they were extinguished in minutes, so that were was not trouble but smoke.
NO METEORITE FRAGMENTS hit the city, all the damage is done by shock wave only.

>>So I additionally am led to speculate the zinc factory was hit by a fragment
No, it was done by shock wave. In this particular case, it is the fault of factory administration - the building was overdue for major repair. The buildings next to that one have all the windows intact. This place is approximately 7 km north from epicenter.

>>No other structural collapses from the shock wave
There are two cases in the epicenter - partial roof collapse of ChTPZ (ЧТПЗ) factory, both heavy injuries are from that place, and the second - Ice Sports Arena's canopy destroyed.

The explosion was at 40 km altitude, it was still VERY supersonic, and on very shallow trajectory. So, to hit the city the fragments would have to turn almost 90 deg - that's impossible.
All the impact sites found so far are at least 80 km from the city.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: smoliarm on 02/17/2013 01:14 AM

In the beginning I thought it was a fragment, too, but Occam's razor suggests the much simpler explanation of the (old?) roof  collapsing due to overpressure.
You are right - the roof was not only old, it was damaged last year and not repaired. They had several warnings, but they just did not do the repair.

Quote
Also technically, a fragment can't outpace a shockwave,
Actually, it can :)

Quote
it would produce its own shockwave instead
And that's what it did :)
- in both confirmed impact sites eyewitnesses describe it exactly this way.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: sanman on 02/17/2013 01:17 AM
Russia proposes common space defense system:

http://www.globalresearch.ca/the-militarization-of-space-russian-deputy-prime-minister-calls-for-new-space-defense-system/5323168

http://news.xinhuanet.com/english/world/2013-02/16/c_124351175.htm
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: rdale on 02/17/2013 01:21 AM
So the world's reaction to the event can be summed up like this: "Not in our backyard". What saddens me the most that it would take a direct hit with mass casualties until pociticians in power will get their asses up and actually do something about that...

...which they should... More people die in one month from flooding than in a century from meteors.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Nittany Lion on 02/17/2013 01:36 AM
More people die in one month from flooding than in a century from meteors.


Please don’t let The Weather Channel begin naming asteroid flybys.


Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: kevin-rf on 02/17/2013 01:57 AM

Please don’t let The Weather Channel begin naming asteroid flybys.


Why, I think Jim would be a great name ;)

btw. On the humorous side the onion has a cool write-up http://www.theonion.com/articles/more-than-1000-russians-injured-in-freaking-cooles,31321/
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: asmi on 02/17/2013 02:02 AM
...which they should... More people die in one month from flooding than in a century from meteors.
It will take just one "good" hit to turn this statistics upside down. And while the specific town/towns can theoretically be evacuated in time for the event, imagine that tomorrow it is discovered that 1000 meter asteroid is coming our way - what are we going to do about that? We can't evacuate the whole continent, not to mention the whole planet...
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Blackstar on 02/17/2013 02:07 AM
If the cost is $500M, it would seem reasonable considering that NASA has a $17B per year budget. This is the kind of work that NASA is expected to do. If NASA doesn't do this kind of work, taxpayers will eventually question whether their $17B per year "investment" into NASA is put to good use.
The result is that the money has gotten cut out of other things at NASA, and the agency has never really had the resources to accomplish it.

This is just a variation of the common situation of the "unfunded mandate."

In your opinion, is this likely to change given the close pass and Russian impact?

Yeah, probably. But probably only a little bit. To cut to the chase, the US government right now is so dysfunctional that it may not be possible for anything to change, even if it should. If government was properly working, what should happen is that the administration would tie its stated goal of sending humans to an asteroid--for which they are not spending any money--to this new concern and add some money to NASA's budget to fund a space-based survey telescope. (My own view is that they should simply fund the NEOCam Discovery mission proposal. It is not the best way to do the job, but it is probably the most cost effective and least expensive.)

But gazing into my cracked crystal ball, here is likely what is going to happen: Congress will hold hearings, they may put some additional language into a NASA authorization bill (one is supposedly in the planning stages), and they may increase the tracking requirement. They may also call for another study of the issue. (That's not a totally bad idea, although I'd suggest that a smarter thing to do would be to implement some of the recommendations in the last NRC study of the issue.) But the authorization bill will not come with additional money attached, and it will be up to the appropriators and the White House to step forward. They _might_ do that. In fact, the White House has been trying to increase the NEO budget for a few years now (from $6 million to about $20 million)--although nobody I know seems to know where that money is supposed to go. But I refer you back to the "government is broken" stuff above. Currently there is language in the NASA authorization act that calls for detection of 140-meter objects that the administration is not funding. Congress can increase the requirement all it wants and the administration can keep ignoring it.

I think that one thing that doesn't help a lot is that Rohrabacher is the loudest voice on this subject. He's liked by some space enthusiasts, but he's not treated with much respect by his peers. If you watch the hearings in which he participates, it is clear that many of his colleagues don't take his lead. If a more well-respected member of Congress took on this issue it would have better chances. But broken government, there you go.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Nittany Lion on 02/17/2013 02:08 AM

Please don’t let The Weather Channel begin naming asteroid flybys.


Why, I think Jim would be a great name ;)



If I die from Asteroid Jim I’m gonna be so upset!


Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Blackstar on 02/17/2013 02:21 AM
I should add that there's something that Congress could do in an authorization bill that would be worthwhile and would not cost (much) money. They could require DoD to share the data it has recorded on infrared events in the upper atmosphere with scientists who possess the appropriate security clearances. US missile warning satellites regularly record the reentry of space debris as well as meteors. But that data is not made available to the asteroid tracking community so that they can validate their models on how much material enters the atmosphere. That would be a useful thing for them to do.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: lcs on 02/17/2013 02:39 AM
The timing would be coincidental, but not incredible - no doubt the meteor was still supersonic at the time of breakup, so the fragment would at first outpace the shockwave, then slow below supersonic, with the shockwave just happening to catch up to it again at about the same time it hit the ground.

Most videos I've seen don't seem to do justice to the sound and power of that shockwave, ironically it's this low quality video that I think captures it best:

http://www.youtube.com/watch?v=b0cRHsApzt8

I have little trouble believing this kind of thing could explain the damage seen at that zinc factory.

To my ear on this video there sounds like a precursor to the shock wave, about 2 seconds before the blast hits.  Been scratching my head over what that is.  Precursors have been noted around nuclear detonations (but with much higher overpressures in the main blast).  Also on several Russian handheld videos I noticed erratic camera movements just a half-second or so before the sound hits. 
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: kevin-rf on 02/17/2013 02:58 AM
I should add that there's something that Congress could do in an authorization bill that would be worthwhile and would not cost (much) money. They could require DoD to share the data it has recorded on infrared events in the upper atmosphere with scientists who possess the appropriate security clearances. US missile warning satellites regularly record the reentry of space debris as well as meteors. But that data is not made available to the asteroid tracking community so that they can validate their models on how much material enters the atmosphere. That would be a useful thing for them to do.

I wonder if part of the reason they no longer share the data (apart from general paranoia) is sharing the data lets an adversary characterize the lower limits and sensitivity of the system along with maybe the scan rate and any coverage gaps that may (or may not) exist. The way around this would be to set a lower limit on what events they share and maybe degrade the data somewhat. So you don't share a 0.1 meter rock, you only do the events that are not large enough to be missed. The 1000 meter rocks ;)
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: majormajor42 on 02/17/2013 03:04 AM
aerial photo:
@AstroTerry
Quote
A friend sent me this from Russia, a pilot took a pic of the#RussianMeteor from the cockpit. Amazing! pic.twitter.com/v3gkBjfo10:11am - 16 Feb 13

Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: jcm on 02/17/2013 03:04 AM

Please don’t let The Weather Channel begin naming asteroid flybys.


Why, I think Jim would be a great name ;)



If I die from Asteroid Jim I’m gonna be so upset!




I'm glad mine is safely in the main belt, how embarrassing would it be for your name to be forever associated with an extinction event? 

Very interesting about the zinc factory and the other secondary effects
from the shock wave.

It seems like the California, Cuba and Japanese fireballs are all small and just regular background events that are  being noticed because fireballs are in the news.

Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: GM4BRB - 5DecadesinSpace on 02/17/2013 03:44 AM

[...]

The explosion was at 40 km altitude, it was still VERY supersonic, and on very shallow trajectory. So, to hit the city the fragments would have to turn almost 90 deg - that's impossible.
All the impact sites found so far are at least 80 km from the city.

Thanks for this. I was unable to get to sleep still cogitating on the fact I didn't remember anyone saying at what altitude the Meteor exploded. I also noted that early posts seemed to infer that it was Supersonic Fragments causing the Blasts. It's clear that this was a blast from an airburst.

Trawling through Youtubes I settled on about 2 mins between the fireball and the arrival of the sonic-blasts, though it's really hard to find continuity in any of the vids. However, 2 mins delay would equate to 40km already seeing Speed of sound in air = 330m/s-1 approx.

Спасибо и до свидания на данный момент.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Blackstar on 02/17/2013 04:13 AM
I wonder if part of the reason they no longer share the data (apart from general paranoia) is sharing the data lets an adversary characterize the lower limits and sensitivity of the system along with maybe the scan rate and any coverage gaps that may (or may not) exist. The way around this would be to set a lower limit on what events they share and maybe degrade the data somewhat. So you don't share a 0.1 meter rock, you only do the events that are not large enough to be missed. The 1000 meter rocks ;)

I'm not sure that they ever regularly shared the data. In the mid-1990s or so Pete Worden, then in the USAF (not sure if he had gotten his star yet) managed to get some data shared. But apparently this was a single time thing and not a regular occurrence. I think that they don't share the data not because of any particular secrecy concerns, but because they don't have to, nobody has made them do it, and they don't see any reason that they should.

And there is no real security concern that cannot be addressed with proper safeguards. There are lots of scientists who get security clearances and are allowed access to very sensitive data. They have to scrub it and get permission to publish, but there are procedures for doing this. For instance, reconnaissance satellite photos have been used to count seals in the Arctic and whales at sea because scientists got clearances. I know a guy who had solar radiation sensors mounted on DSP satellites, whose locations were classified information. In the case of the IR warning data, they could simply set a threshold and say "you cannot comment on anything below X." Or they could preserve the security aspects by binning the data, so that they could say that there were Y number of events below threshold X, but not indicating how many of them were way below that limit. It should be solvable, it just requires somebody willing to do it.

This event might cause some people to wake up about this issue.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: kevin-rf on 02/17/2013 04:40 AM
Didn't realize that was a one time event, I thought they had been sharing up to some point in the recent past when they stopped. Thanks for the backstory.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: sanman on 02/17/2013 04:53 AM
aerial photo:
@AstroTerry
Quote
A friend sent me this from Russia, a pilot took a pic of the#RussianMeteor from the cockpit. Amazing! pic.twitter.com/v3gkBjfo10:11am - 16 Feb 13

Wow - that's pretty cool. Was that pic taken around the same time the actual explosion occurred? How would the plane have been affected by being in the air when that happened? Wouldn't it have been hit by the shockwave and have lost control?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: iamlucky13 on 02/17/2013 05:02 AM
Quote
Also technically, a fragment can't outpace a shockwave, it would produce its own shockwave instead - which would have been heard for something big enough to cave in a roof.

It would produce a smaller shockwave than the airburst event. The shockwave from a supersonic fragment probably less than a meter in size probably wouldn't propagate 20+ km, and would utterly pale in comparison to the 500 kT of energy estimate to have been released to the atmosphere by the main disintegration.

There were several fires in the city - all in industrial buildings, and all from heating oil burners damaged by shock wave. Fortunately, they were extinguished in minutes, so that were was not trouble but smoke.
NO METEORITE FRAGMENTS hit the city, all the damage is done by shock wave only.

Since you're from Russia, I will take your word as having more thorough news coverage than the English sources can provide.

Quote
The explosion was at 40 km altitude, it was still VERY supersonic, and on very shallow trajectory. So, to hit the city the fragments would have to turn almost 90 deg - that's impossible.
All the impact sites found so far are at least 80 km from the city.

I was only speculating before, but your reference to the distance downrange for other impacts convinces me.

The smoke trail certainly appeared to point much further downrange, but getting an accurate perspective of the angle of distant lines is hard enough with stable videos. I didn't trust my eyes on that one.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: sanman on 02/17/2013 05:09 AM
So how much material could be recoverable from this meteor hit?

I was reading that there's a big rush to gather pieces and sell them for cash:

http://abcnews.go.com/International/russian-meteor-rushing-cash-blast/story?id=18522807
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: 360-180 on 02/17/2013 06:14 AM
So how much material could be recoverable from this meteor hit?

I was reading that there's a big rush to gather pieces and sell them for cash:

http://abcnews.go.com/International/russian-meteor-rushing-cash-blast/story?id=18522807
"Authorities have sent divers into a frozen lake outside the city, where a large chunk of the meteor is believed to have landed, creating a large hole in the ice. By the end of the day they had not found anything."
large hole in the ice made by fishermen ;D

bolid trace from plane at 34000 ft level
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: ugordan on 02/17/2013 10:55 AM
The shockwave from a supersonic fragment probably less than a meter in size probably wouldn't propagate 20+ km

I don't know why you conclude that since small bolides have been known to produce very audible sonic booms indicating that such shockwaves can readily propagate to the ground. We're talking about a highly, not marginally supersonic object which carries a lot of energy and is rapidly slowed down. That energy has to go somewhere.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Zan Tiala Thraeki Dica on 02/17/2013 11:32 AM
Do you know that if we follow the strait direction of Chelyabinsk asteroid through Earth we find out the Eastern Island? Does anyone measured the asteroid impact on Earth's crust ?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: smoliarm on 02/17/2013 11:48 AM
...
There were several fires in the city - all in industrial buildings, and all from heating oil burners damaged by shock wave. Fortunately, they were extinguished in minutes, so that were was not trouble but smoke.
NO METEORITE FRAGMENTS hit the city, all the damage is done by shock wave only.

Since you're from Russia, I will take your word as having more thorough news coverage than the English sources can provide.

...

You are lucky indeed you have not read Russian news on this subject :) The amount of nonsense is incredible.
Of course, my info is NOT from the news, here are the sources (sorry I did not give them in the first place):
OF FIRES - firefighter's reports from the first day;
BUILDING DAMAGE - 1. Major's office reports and 2. School District Office reports. Interestingly, elementary school principals produced more accurate and FAST reports - by FAR, compared to other offices :)
IMPACT CRATERS and SITES (search and confirmations) - Emergency HQ press-conference transcripts and private communications.

With respect to some statements from officials that no meteorite material found -
The officials have to deal now with one more real trouble: hundreds (or thousands) of meteorite hunters. So, it is my guess that they do not release any info on fragment found intentionally. And it's quite wise, they can't secure impact sites properly, all the police and emergency crews are busy fixing the windows (it was -20 C last night).

Finally, about the altitude of explosion - it is from my calculation described here
http://forum.nasaspaceflight.com/index.php?topic=31118.msg1013503#msg1013503
(I used average speed of sound of 305 m/sec, estimate from this graph http://en.wikipedia.org/wiki/File:Comparison_US_standard_atmosphere_1962.svg (http://this graph http://en.wikipedia.org/wiki/File:Comparison_US_standard_atmosphere_1962.svg))
One of my students did the same kind calculation on different surveillance recording, with the same result:
Altitude of explosion = 41 ± 0.5 km
Another student went different way - she collected videos and pictures from KNOWN locations  20 to 150 km away, made from different directions (from West to SE). She made classic triangulation, trying to correct for focal length of lenses using naturally strait lines in view (buildings, roads, wires etc.) I was pretty skeptical, but she got 44 ± 5 km in the end :)


Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: RichardAKJ on 02/17/2013 11:53 AM
If the cost is $500M, it would seem reasonable considering that NASA has a $17B per year budget. This is the kind of work that NASA is expected to do. If NASA doesn't do this kind of work, taxpayers will eventually question whether their $17B per year "investment" into NASA is put to good use.
The result is that the money has gotten cut out of other things at NASA, and the agency has never really had the resources to accomplish it.

This is just a variation of the common situation of the "unfunded mandate."

In your opinion, is this likely to change given the close pass and Russian impact?

Yeah, probably. But probably only a little bit. To cut to the chase, the US government right now is so dysfunctional that it may not be possible for anything to change, even if it should. If government was properly working, what should happen is that the administration would tie its stated goal of sending humans to an asteroid--for which they are not spending any money--to this new concern and add some money to NASA's budget to fund a space-based survey telescope. (My own view is that they should simply fund the NEOCam Discovery mission proposal. It is not the best way to do the job, but it is probably the most cost effective and least expensive.)

But gazing into my cracked crystal ball, here is likely what is going to happen: Congress will hold hearings, they may put some additional language into a NASA authorization bill (one is supposedly in the planning stages), and they may increase the tracking requirement. They may also call for another study of the issue. (That's not a totally bad idea, although I'd suggest that a smarter thing to do would be to implement some of the recommendations in the last NRC study of the issue.) But the authorization bill will not come with additional money attached, and it will be up to the appropriators and the White House to step forward. They _might_ do that. In fact, the White House has been trying to increase the NEO budget for a few years now (from $6 million to about $20 million)--although nobody I know seems to know where that money is supposed to go. But I refer you back to the "government is broken" stuff above. Currently there is language in the NASA authorization act that calls for detection of 140-meter objects that the administration is not funding. Congress can increase the requirement all it wants and the administration can keep ignoring it.

I think that one thing that doesn't help a lot is that Rohrabacher is the loudest voice on this subject. He's liked by some space enthusiasts, but he's not treated with much respect by his peers. If you watch the hearings in which he participates, it is clear that many of his colleagues don't take his lead. If a more well-respected member of Congress took on this issue it would have better chances. But broken government, there you go.

Many thanks for your reply, Blackstar. Very informative.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: smoliarm on 02/17/2013 12:34 PM
So how much material could be recoverable from this meteor hit?

I was reading that there's a big rush to gather pieces and sell them for cash:

http://abcnews.go.com/International/russian-meteor-rushing-cash-blast/story?id=18522807
Unfortunately, that's true about big rush :)

It is difficult to tell what is the recoverable fraction - even in the cases of well observed fall and immediately discovered impact site, we never know for sure the original size. I can only give some historic cases
Sikhote-Alin -- ca. 23 tonnes recovered / ca. 100 tonnes est. before entry.
Allende -- 2 tonnes recovered / ca. 15-20 tonnes est. before entry.

It is believed, that for large meteorite (tonne scale) regardless of entry mode at least 2% of original mass fell on the ground (Monica Grady). Richard Hutchison gives higher estimate - 5% - for entry velocity below 15 km/sec.

So, IF we believe the voiced estimate of 7000 tonnes - there are some 140 tonnes of fragments waiting for meteorite hunters :)
IF this estimate turns out to be be realistic - this is the largest meteorite BY FAR in the entire world history. I am looking forward for the next Meteoritics issue with article on details on this estimate. If there will be no such article, it was a joke :)

Little grain of salt: I calculated a minimal amount of smoke produced by 7000 t chondrite assuming 75% of material goes to smoke, @ 40 km altitude @ pressure of 0.003 atm. I ended with ca 20 cubic km of dense smoke. And it does not look like we see it:
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=31118.0;attach=495901;image
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Blackstar on 02/17/2013 01:06 PM
Anybody checked eBay to see if anybody is trying to sell what they claim are pieces of the meteorite yet?

I bet there will be a lot of scams going on very soon.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: ChileVerde on 02/17/2013 01:08 PM
I should add that there's something that Congress could do in an authorization bill that would be worthwhile and would not cost (much) money. They could require DoD to share the data it has recorded on infrared events in the upper atmosphere with scientists who possess the appropriate security clearances. US missile warning satellites regularly record the reentry of space debris as well as meteors. But that data is not made available to the asteroid tracking community so that they can validate their models on how much material enters the atmosphere. That would be a useful thing for them to do.

I wonder if part of the reason they no longer share the data (apart from general paranoia) is sharing the data lets an adversary characterize the lower limits and sensitivity of the system along with maybe the scan rate and any coverage gaps that may (or may not) exist. The way around this would be to set a lower limit on what events they share and maybe degrade the data somewhat. So you don't share a 0.1 meter rock, you only do the events that are not large enough to be missed. The 1000 meter rocks ;)

http://science.slashdot.org/story/09/06/22/1625254/us-military-blocks-data-on-incoming-meteors

Edit: Adds report that the data was going to be unblocked. That doesn't seem to have happened.

Quote

http://blogs.nature.com/news/2009/07/post_30.html

Air Force to resume meteor data sharing

06 Jul 2009 | 16:27 GMT | Posted by Geoffrey Brumfiel

Space.com is reporting that the United States Department of Defense (DOD) is rethinking a decision that cut off astronomers from access to data on incoming meteors.

The DOD has collected the data with a network of satellites and sensors designed to detect atmospheric nuclear detonations. The same sensors can spot a meteor streaking across the sky, and for over a decade, the military has provided astronomers with some of that data on an ad-hoc basis.

As we reported <http://www.nature.com/news/2009/090612/full/459897a.html>, that relationship came to a screeching halt earlier this year, when in March, a memo from Air Force Space Command, which operates the satellites, cautioned against sharing data with scientists. The decision was apparently made because DOD officials were worried that the data could reveal details of the US monitoring system.

But now, Brigadier General Robert Rego, the space command’s mobilization assistant to the director of air, space and nuclear operations, says that the organization is considering once again sharing data with scientists, albeit in a more carefully vetted way. The new process will be faster, more systematic, and it in compliance with classification procedures, he says. It could begin within the next few months.

Even more edit: Rohrabacher was paying attention in 2009; perhaps he'll have something to say now.

Quote
http://www.space.com/6927-military-seeks-common-ground-scientists-fireball-data-flap.html

Military Seeks Common Ground with Scientists on Fireball Data Flap
by Leonard David, SPACE.com's Space Insider Columnist
Date: 03 July 2009 Time: 03:10 PM ET

<much snip>

The flare up about the fireball data release policy has received the attention of U.S. Congressman Dana Rohrabacher, the California lawmaker with a long-time passionate interest in the entire Near Earth Object issue.

"I have been keeping a close eye on this situation, and I am confident the Department of Defense, in cooperation with the scientific community, will find a solution that permits the release of scientifically valuable data without compromising national security," Rohrabacher explained in a statement to SPACE.com.

As for a message to the scientific community, Brigadier General Rego emphasized that there was no intent, and in fact, no change to the data sharing policy. Now underway is a fresh look at ways to improve the relationship and data flow to make it more valuable to scientists.

"I would encourage you to keep your eye out or your ear to the ground with the scientific community...to see if we haven't done some improvements here over the next few months," Rego concluded.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: JimO on 02/17/2013 01:28 PM
I would also be very interested in eyewitness reports of electrophonic sound PRIOR to the acoustic shock -- that is, during the brightest flaring of the fireball. This is a at-long-last well-established effect of plasma-generated radio noise coupling into near-observer physical objects and creating a hissing or whooshing sound. It occurs simo with the visual flares, seems to come from 'all around' [not from above], has been reported for centuries by some bright fireball witnesses and pooh-poohed by scientists until work by Colin Keay and others established its validity. 
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: alexterrell on 02/17/2013 01:32 PM
So the world's reaction to the event can be summed up like this: "Not in our backyard". What saddens me the most that it would take a direct hit with mass casualties until pociticians in power will get their asses up and actually do something about that...

...which they should... More people die in one month from flooding than in a century from meteors.

I would suspect, if you don't live in a flood prone area, you have a higher probability of dying in a meteor impact than in a flood.

It's just unlikely to happen in this Parliament / Presidential Term etc.

If the Chelyabinsk event had been just a little larger, or made of iron, perhaps Russian citizens would be wondering why one of the World's most capable space nations allowed a City to be destroyed.
 
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: ugordan on 02/17/2013 01:37 PM
If the Chelyabinsk event had been just a little larger, or made of iron

What difference would it have made if it was made of iron? Might have not fragmented as easily and hence carried more of its energy downrange, away from Chelyabinsk and into some remote crater.

Edit: unless you were thinking same diameter, not same mass?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: 360-180 on 02/17/2013 01:40 PM
I used average speed of sound of 305 m/sec,
The shortest period between the flash and the shock wave in the video is 89 seconds. Based on this video, you can calculate the height of the explosion is 0.305x89=27.15 km
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: ugordan on 02/17/2013 01:42 PM
The shortest period between the flash and the shock wave in the video is 89 seconds. Based on the height of the explosion is 0.305x89=27.15 km

Can you post a link to that video? The shortest I've seen yet was still over 2 minutes.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: JohnFornaro on 02/17/2013 01:47 PM
perhaps Russian citizens would be wondering why one of the World's most capable space nations allowed a City to be destroyed.

Get a dictionary.

If the Russians knew it was coming, knew where it was going to hit, had in hand the means to destroy it, and did not take action, then you could say they "allowed" the meteor to strike anyhow.

Instead, they didn't know it was coming, didn't know where it would hit, didn't have a means to destroy it, and not too surprisingly, didn't take any action.

No allowances here.  Move along.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: JohnFornaro on 02/17/2013 01:48 PM
I would also be very interested in eyewitness reports of electrophonic sound PRIOR to the acoustic shock -- that is, during the brightest flaring of the fireball. This is a at-long-last well-established effect of plasma-generated radio noise coupling into near-observer physical objects and creating a hissing or whooshing sound. It occurs simo with the visual flares, seems to come from 'all around' [not from above], has been reported for centuries by some bright fireball witnesses and pooh-poohed by scientists until work by Colin Keay and others established its validity. 

Thanks for the "learn something new every day" comment.  I had not known of this.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: 360-180 on 02/17/2013 01:51 PM
Can you post a link to that video? The shortest I've seen yet was still over 2 minutes.
http://youtu.be/yfEaUT2yr-A 'Метеорит. Коркино.'
Car DVR recording was made. Recording been mounting. But the gap can be calculated from the timestamp in the bottom left corner. 43:05 flash,  44:34 shock wave.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: ugordan on 02/17/2013 02:10 PM
Thanks!
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: smoliarm on 02/17/2013 02:39 PM
...
http://youtu.be/yfEaUT2yr-A 'Метеорит. Коркино.'
Car DVR recording was made. Recording been mounting. But the gap can be calculated from the timestamp in the bottom left corner. 43:05 flash,  44:34 shock wave.

Thanks a lot!! This looks authentic. Moreover, from shades movement it was VERY close to epicenter, the source of light is moving right overhead. And amazingly - the shock effect is quite mild, it was barely able to shake off some show from roofs and no damage at all.
I'll pass this video to my students, we will look more into this.
Thanks.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: ChileVerde on 02/17/2013 02:41 PM
I would also be very interested in eyewitness reports of electrophonic sound PRIOR to the acoustic shock -- that is, during the brightest flaring of the fireball. This is a at-long-last well-established effect of plasma-generated radio noise coupling into near-observer physical objects and creating a hissing or whooshing sound. It occurs simo with the visual flares, seems to come from 'all around' [not from above], has been reported for centuries by some bright fireball witnesses and pooh-poohed by scientists until work by Colin Keay and others established its validity. 

Interesting history of this at http://www.gefsproject.org/electrophones/index_history.html
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: 360-180 on 02/17/2013 02:53 PM
And amazingly - the shock effect is quite mild
These roofs do not have windows.  ;)
And besides, there is no reflection of the shock waves from the earth's surface.

In the town Korkino meteorite smashed many windows too
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: ChileVerde on 02/17/2013 02:56 PM
...
http://youtu.be/yfEaUT2yr-A 'Метеорит. Коркино.'
Car DVR recording was made. Recording been mounting. But the gap can be calculated from the timestamp in the bottom left corner. 43:05 flash,  44:34 shock wave.

Thanks a lot!! This looks authentic. Moreover, from shades movement it was VERY close to epicenter, the source of light is moving right overhead. And amazingly - the shock effect is quite mild, it was barely able to shake off some show from roofs and no damage at all.
I'll pass this video to my students, we will look more into this.
Thanks.

>  Коркино

That's at 54.90, 61.40, about 30 km south of Chelyabinsk proper.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: JohnFornaro on 02/17/2013 02:58 PM
Another dash cam.  This one in SF.  Unrelated, exept in time:

http://www.youtube.com/watch?feature=player_embedded&v=HLpTOc1i8_8
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: JimO on 02/17/2013 03:01 PM
I would also be very interested in eyewitness reports of electrophonic sound PRIOR to the acoustic shock -- that is, during the brightest flaring of the fireball. This is a at-long-last well-established effect of plasma-generated radio noise coupling into near-observer physical objects and creating a hissing or whooshing sound. It occurs simo with the visual flares, seems to come from 'all around' [not from above], has been reported for centuries by some bright fireball witnesses and pooh-poohed by scientists until work by Colin Keay and others established its validity. 

Thanks for the "learn something new every day" comment.  I had not known of this.

Happy to take my turn informing -- I'm gratefully on the receiving end as a rule on high-quality threads such as these.

We got a handle on electrophonic sounds in the early 1980s when reentering Orbiters crossed the skies of Texas, and witnesses began reporting HEARING the hissing overflight in real time. 'Like a skier down a slope', one said; 'like a quiet-motor powerboat passing through a choppy lake', said another. I watched many overflights, and heard nothing until the long-after dull THUD. But it seems to really depend on lucky coincidences of specific materials near the observer -- dry pine needles, a tin wall, even frizzy hair, all seem to have worked, but I was out on an open street near empty fields.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Mongo62 on 02/17/2013 03:07 PM
Can you post a link to that video? The shortest I've seen yet was still over 2 minutes.
http://youtu.be/yfEaUT2yr-A 'Метеорит. Коркино.'
Car DVR recording was made. Recording been mounting. But the gap can be calculated from the timestamp in the bottom left corner. 43:05 flash,  44:34 shock wave.
I was pleased to see this.  I was finding it difficult to reconcile the estimated explosion energy (500 kilotons) and the implied altitude (about 52 km) from a 140s shock wave travel time with the observed damage.  The much lower airburst altitude implied from a 90s travel time (about 29 km) would result in an overpressure about three times greater when it reaches the ground, which is sufficient to do the observed damage.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: 360-180 on 02/17/2013 03:17 PM
In the town Korkino meteorite smashed many windows too
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: smoliarm on 02/17/2013 03:17 PM
...
What difference would it have made if it was made of iron? Might have not fragmented as easily and hence carried more of its energy downrange...

Exactly.
Also, compared to stone meteorites, irons are much more dense, specific gravity of iron meteorites is 7.9 g/cm3, most stony meteorites have about 3 g/cm3. Therefore, irons tend to carry their energy in larger pieces (or, less fragmentation), they conserve more energy (lower surface/mass ratio -> lower drag), and they bring their energy to lower altitude, where explosion makes much stronger shock wave (due to higher atm. pressure).


Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Danderman on 02/17/2013 04:04 PM
I am wondering if the cause of the mysterious rogue waves that appear in the middle of the ocean might be asteroid impacts even further out in the ocean.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: smoliarm on 02/17/2013 05:21 PM
I would also be very interested in eyewitness reports of electrophonic sound PRIOR to the acoustic shock -- that is, during the brightest flaring of the fireball. This is a at-long-last well-established effect of plasma-generated radio noise coupling into near-observer physical objects and creating a hissing or whooshing sound. It occurs simo with the visual flares, seems to come from 'all around' [not from above], has been reported for centuries by some bright fireball witnesses and pooh-poohed by scientists until work by Colin Keay and others established its validity. 

I never herd of this effect, thanks for the reference.
In this case, all the eyewitness reports that I saw have no such thing, most people noted that fireball looked powerful, magnificent, and - amazingly silent. However, we should remember that it was busy morning in a big city, the background noise was significant.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: R7 on 02/17/2013 05:54 PM
Many videos seem to show that there was twin contrail from the beginning of reentry. Weird? Are the aerodynamic forces big enough to brake the meteor before contrail begins to form?

Propeller hat idea 1: It did skip elsewhere, broke and two pieces reentered

Propeller hat idea 2: Moon perturbed and broke it in the process.

Propeller hat idea 3: The Bugs have discovered a chain shot.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: sanman on 02/17/2013 06:18 PM
I, for one, welcome our Klendathu arachnid overlords
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Star One on 02/17/2013 06:24 PM
Quote
The meteorite that caused devastation in the Urals on Friday could have struck Britain if it had entered the atmosphere at only a slightly different time of day, astronomers revealed yesterday.

The region around Chelyabinsk hit by the meteorite impact is 55 degrees north, the same latitude as northern England. Had the meteorite's timing been only few hours different, it could have caused widespread damage in the British Isles, astronomers at the University of Hawaii said yesterday.

http://www.guardian.co.uk/science/2013/feb/16/meteorite-uk

No doubt applicable to other land masses along the same latitude.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: ugordan on 02/17/2013 06:31 PM
Many videos seem to show that there was twin contrail from the beginning of reentry. Weird?

I've been thinking about this as well. Seems implausible to me that it was a binary from the moment it entered atmosphere or that it split into two roughly equal pieces so soon after entry. Also, I don't believe we've ever really seen a big meteor vapor trail like this from almost underneath. A unique vantage point.

I'm wondering if it was convection that split it in two. When you have a spherical mass of hot air (like a nuclear fireball), convective movement and resulting vacuum effects quickly produce a rotating toroidal cloud. Maybe what we see here is is what happens with a  "cylindrical" fireball? It splits into two, like a cross section of a toroidal cloud?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: suncity on 02/17/2013 08:51 PM
I think this is really simple: if you look at the contrails they are counter rotating. This is exactly what you see when any aircraft flies thru a condensation zone, two contrails are generated from the opposite wingtips because there is higher pressure under the wing & lower pressure on the upper side and some air "leaks" from below the wing to the upper side generating 2 vortexes.

The meteor was probably symmetrical and was generating some lift and left counter rotating contrails emanating from the "wingtips". This is not so unusual, just consider that Apollo and SpaceX's Dragon generate lifts due to their shape and offset center of gravity even if they don't look like a conventional airplane. The shape of the meteor was probably oblong, reminiscent of a lifting body, and it happened to fly in a stable asset.

No need to assume a clean split in 2 equally-sized fragment to explain the dual contrail.   

EDIT: I think that the post below from 360-180 perfectly explains the dual contrails: the rising hot air from the center of the meteor path split the initial single trail creating the 2 vortexes. Brilliant.   

Many videos seem to show that there was twin contrail from the beginning of reentry. Weird?

I've been thinking about this as well. Seems implausible to me that it was a binary from the moment it entered atmosphere or that it split into two roughly equal pieces so soon after entry. Also, I don't believe we've ever really seen a big meteor vapor trail like this from almost underneath. A unique vantage point.

I'm wondering if it was convection that split it in two. When you have a spherical mass of hot air (like a nuclear fireball), convective movement and resulting vacuum effects quickly produce a rotating toroidal cloud. Maybe what we see here is is what happens with a  "cylindrical" fireball? It splits into two, like a cross section of a toroidal cloud?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: the_roche_lobe on 02/17/2013 09:12 PM
Propeller hat idea 1: It did skip elsewhere, broke and two pieces reentered
Propeller hat idea 2: Moon perturbed and broke it in the process.
Propeller hat idea 3: The Bugs have discovered a chain shot.


4. Binary/contact asteroid?

P
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: smoliarm on 02/17/2013 09:15 PM
Many videos seem to show that there was twin contrail from the beginning of reentry. Weird? Are the aerodynamic forces big enough to brake the meteor before contrail begins to form?

Propeller hat idea 1: It did skip elsewhere, broke and two pieces reentered

Propeller hat idea 2: Moon perturbed and broke it in the process.

Propeller hat idea 3: The Bugs have discovered a chain shot.

Viktor Gorohvski from Ural State University have just released the results of first analyses of the recovered fragments of meteorite:
http://www.gazeta.ru/social/news/2013/02/17/n_2759605.shtml
It belongs to H-chondrites, not surprisingly as it is the most abundant type.
They are pretty brittle, e.g. you can crush H3 just with bare fingers. I did it many times - placing the sample in thin-wall Teflon tube and squeezing it then with fingers. So, it is like the weakest sandstone, even worse.
H5 and H6 are stronger, you can compare them with lowest grade concrete, poorly processed. Fingers aren't enough, but light hummer will do.

>>Many videos seem to show that there was twin contrail from the beginning of reentry. Weird?
Not weird at all, like I said they are not very robust.

>>Are the aerodynamic forces big enough to brake the meteor before contrail begins to form?
Yes, and not forget the gravitational forces - they are big enough, too.

>>Propeller hat idea 2: Moon perturbed and broke it in the process.
Earth can do this on its own :)

About another larger guy - DA14 - I read in the news (don't remember the exact ref) that NASA is going to look for signs of surface displacement. That is exactly it - as asteroid closes to Earth, the forces which alter its trajectory also try to alter its shape. It may crack :)
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mr_magoo on 02/17/2013 09:36 PM
It had the yield of the largest warhead carried by US nuclear submarines.   Lucky that it detonated high and wide of that town.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: smoliarm on 02/17/2013 09:43 PM
...
No need to assume a clean split in 2 equally-sized fragment to explain the dual contrail.   
...

As I see it, there were two major fragments from the very beginning of contrail, they were spinning slowly in the opposite directions. During the flight, their mass was changing rapidly, especially when the glow started. At the end, they were clearly of different size (may be, by order of magnitude). The smaller one "went off" first - it was the first bright flash. About 1 sec later the large one exploded - it was the second and the brightest flash.
On some videos you can see that there were at least two more fragments, much smaller. they continued flight for a while, with much thinner trail, then they burst too in a small double flash.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: sanman on 02/18/2013 12:30 AM
So tell me - I have a friend who comes from Ufa - how far is it located from the impact area?

It seems to me that when I look on a map, it's quite close, about 200 miles southwest of Chelyabinsk. But the meteor came down about 100 miles southwest of Chelyabinsk, didn't it?

Were other Russian cities affected by the blast?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: sanman on 02/18/2013 01:51 AM
This vid gives quite a close up look at the contrails, so that you can see their shape in more detail:

http://goo.gl/RieBI

Hmm, had to use a shortener, since the filter here seems to be blocking me from posting the youtube URL directly.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Antares on 02/18/2013 02:37 AM
Fingers aren't enough, but light hummer will do.
::)


I think this is really simple....

The meteor was probably symmetrical
Sir Ockham called.  He wants his razor back.


There is literature that says parallel, simultaneous trails are due to the prior breakup of a single meteoroid.  They are very common with smaller meteors.  No reason it couldn't be for a 15m one as well.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: 360-180 on 02/18/2013 03:34 AM
Convection current dragged up the middle of the cloud. lateral parts remained at its height. Therefore, when looking from the bottom seems to be two tracks. In fact, one track has been transformed like at atmospheric nuclear explosion appears mushroom cloud.
 
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: ugordan on 02/18/2013 07:12 AM
Convection current dragged up the middle of the cloud. lateral parts remained at its height. Therefore, when looking from the bottom seems to be two tracks. In fact, one track has been transformed like at atmospheric nuclear explosion appears mushroom cloud.

So my guess was right?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: bubbagret on 02/18/2013 07:17 AM
Convection current dragged up the middle of the cloud. lateral parts remained at its height. Therefore, when looking from the bottom seems to be two tracks. In fact, one track has been transformed like at atmospheric nuclear explosion appears mushroom cloud.
 

Spot on.... I'm sure helped by the fact that a hypersonic object punched a relatively horizontal, tube shaped superheated hole in the atmosphere. It almost looks like the wake of a fast moving boat.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Dalhousie on 02/18/2013 08:04 AM
Viktor Gorohvski from Ural State University have just released the results of first analyses of the recovered fragments of meteorite:
http://www.gazeta.ru/social/news/2013/02/17/n_2759605.shtml
It belongs to H-chondrites, not surprisingly as it is the most abundant type.
They are pretty brittle, e.g. you can crush H3 just with bare fingers. I did it many times - placing the sample in thin-wall Teflon tube and squeezing it then with fingers. So, it is like the weakest sandstone, even worse.
H5 and H6 are stronger, you can compare them with lowest grade concrete, poorly processed. Fingers aren't enough, but light hummer will do.

http://en.wikipedia.org/wiki/H_chondrite

http://www.meteoris.de/class/H-Group.html
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: 360-180 on 02/18/2013 09:14 AM
And amazingly - the shock effect is quite mild

Found another video of Korkino. But the windows were broken. The delay 89s too.  0:07 flash,  1:36 shock wave. http://www.youtube.com/watch?v=Ryd-dDi9GYs
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Ben the Space Brit on 02/18/2013 09:45 AM
[0:07 flash,  1:36 shock wave.

That is the 'perfect storm' that led to so many people being injured, IMHO.  There is the flash and you instinctively move towards it to assess what it was - is it a threat? About 90 seconds later, the windows get blown in by a supersonic shock-wave.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Artyom. on 02/18/2013 10:22 AM
Meteorite Fragments Found in Icy Urals Lake - Scientists

 The fragments of a meteorite that hit Russia’s Urals on Friday, injuring more than 1,000 people in the area, have been found by scientists in Lake Chebarkul, in the Chelyabinsk Region.

“We have just completed the study, we confirm that the particulate matters, found by our expedition in the area of Lake Chebarkul indeed have meteorite nature,” Viktor Grohovsky of the Urals Federal University said.
“This meteorite is an ordinary chondrite, it is a stony meteorite which contains some 10 percent of iron. It is most likely to be named Chebarkul meteorite,” Grohovsky said.

http://en.ria.ru/russia/20130217/179531203/Meteorite-Fragments-Found-in-Icy-Urals-Lake---Scientists.html
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: hektor on 02/18/2013 10:30 AM
No damage to any airborne aircraft by shockwave reported ? amazing.

I would even have expected dead birds falling from the sky
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: DLR on 02/18/2013 10:39 AM
Could it be that impact events - especially those caused by small to mid-size objects - are more common than currently believed by the scientific mainstream?

Some scientists think that impacts are more common, but most do not leave any easily observable geophysical evidence because they occur over the oceans. They link major social and climatic change to impact events, including Noah's Great Flood.

http://en.wikipedia.org/wiki/Holocene_Impact_Working_Group
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: ugordan on 02/18/2013 10:46 AM
I would even have expected dead birds falling from the sky

Huh, why?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: R7 on 02/18/2013 10:59 AM
I would even have expected dead birds falling from the sky

Huh, why?

Indeed. It didn't kill people, smaller creatures are even more resilient.

Btw the convection/vortex explanation for twin contrails makes good sense IMO too.

edit:
Quote
Found another video of Korkino.

Again, nobody pays any attention to sudden very bright flash. What has happened to Duck'n'Cover  :)
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: hektor on 02/18/2013 11:57 AM
Smaller creatures have smaller, more brittle bones.

More to the point: no report from any aircraft ?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: ugordan on 02/18/2013 12:06 PM
You are hugely underestimating the resiliency of birds.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: 360-180 on 02/18/2013 12:24 PM
More to the point: no report from any aircraft ?
Of course, there are about shooting down planes, UFOs, about the living dead. All messages are present  ;)
 New details: Chelyabinsk meteorite nearly knocked flying plane
http://top.rbc.ru/incidents/18/02/2013/845564.shtml

http://translate.google.com/translate?hl=en&sl=ru&tl=en&u=http%3A%2F%2Ftop.rbc.ru%2Fincidents%2F18%2F02%2F2013%2F845564.shtml
 
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: sanman on 02/18/2013 01:21 PM
Scientists are studying pieces of the meteor which have been found:

http://www.latimes.com/news/world/worldnow/la-fg-wn-russian-meteor-study-20130218,0,7219368.story

Quote
The samples were without doubt meteorites, Viktor Grokhovsky, a member of the Russian Academy of Sciences meteorite committee, said early Monday.

"We are certainly dealing with the debris of the object that traveled here from outer space, and, based on the initial examination, we can now say that the object was a regular chondrite, which contained at least 10% metallic iron and nickel alloy as well as shrysolite and sulfite,” Grokhovsky, who is a professor at Yekaterinburg-based Urals Federal University, said in a phone interview.

(http://www.trbimg.com/img-512210e0/turbine/la-fg-wn-russian-meteor-study-20130218-001/580/580x372)

Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: JohnFornaro on 02/18/2013 01:38 PM
Interesting history of this at http://www.gefsproject.org/electrophones/index_history.html

The links to Colin Keay's and Phil Bagnall's home pages are dead on that link.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: JimO on 02/18/2013 02:42 PM
Interesting history of this at http://www.gefsproject.org/electrophones/index_history.html

The links to Colin Keay's and Phil Bagnall's home pages are dead on that link.


Use the 'Wayback Machine' and get:

http://web.archive.org/web/19990128124350/http://users.hunterlink.net.au/~ddcsk/

Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 02/18/2013 02:55 PM
Interesting history of this at http://www.gefsproject.org/electrophones/index_history.html

The links to Colin Keay's and Phil Bagnall's home pages are dead on that link.


Use the 'Wayback Machine' and get:

http://web.archive.org/web/19990128124350/http://users.hunterlink.net.au/~ddcsk/


BTW, I saw your stint on NBC, it looked good.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: JimO on 02/18/2013 03:05 PM
More to the point: no report from any aircraft ?
New details: Chelyabinsk meteorite nearly knocked flying plane
http://top.rbc.ru/incidents/18/02/2013/845564.shtml

I note no mention of any shock wave, nor of number of passengers. Are there other articles that mention those data?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: edkyle99 on 02/18/2013 03:22 PM
Again, nobody pays any attention to sudden very bright flash. What has happened to Duck'n'Cover  :)
We're going to have to educate ourselves about the danger of meteor shock waves, just as we've in recent years learned more about tsunamis.  These are both rare occurrences, but in both cases few remember the safety lessons passed down from many years ago.

 - Ed Kyle
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 02/18/2013 03:25 PM
...
edit:
Quote
Found another video of Korkino.

Again, nobody pays any attention to sudden very bright flash. What has happened to Duck'n'Cover  :)
It hasn't been entirely forgotten:
http://www.nytimes.com/2013/02/17/world/europe/russians-seek-clues-and-count-blessings-after-meteor-blast.html
Quote
Overshadowing these misfortunes, a fourth-grade teacher in Chelyabinsk, Yulia Karbysheva, was being hailed as a hero for saving 44 children from glass cuts by ordering them to hide under their desks when she saw the flash. Having no idea what it was, she executed a duck-and-cover drill from the cold war era.

Ms. Karbysheva, who remained standing, was seriously lacerated when glass severed a tendon in one of her arms, Interfax reported; not one of her students suffered a cut.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: JohnFornaro on 02/18/2013 04:03 PM
JimO:  Thanks!
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: 360-180 on 02/18/2013 04:37 PM
I note no mention of any shock wave, nor of number of passengers. Are there other articles that mention those data?

If you are not afraid of difficulties of the Russian language is look at these links
http://aviaforum.ru/showthread.php?p=1273679 #12142
http://www.forumavia.ru/forum/6/3/3165461623925194599431360990763_1.shtml?topiccount=6


Pilots usually say that the planes not rigid and difficult to break like glass
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Warren Platts on 02/18/2013 05:35 PM
Well, yes, but the question of what 0.5 $G buys in either case arises.

I.e., suppose that amount of money buys a pretty complete assessment of asteroid risk that can be followed up with more $$ on prevention/ mitigation.

You then have to figure out how the same amount of money can be spent on earthquake risk assessment and prevention/mitigation.

In the case of earthquakes, we probably aren't going to prevent them any time soon, so does the 0.5 $G go into earthquake resistant construction in Haiti, Iran and other quaky places? And how much of the population gets protected for that amount of money?

It's not an easy calculation to make. But with space programs, the costs are immense compared to other things. It's easy to say "we should do this space thing" but forget that the money could have better value somewhere else.
And yet, we don't do it JUST because of an actuarial cost-benefit analysis. Very little of what NASA does would qualify, maybe some of the stuff in aeronautics.

And again, there is an existential aspect of it that isn't captured in an actuarial perspective and it's one that doesn't really apply to earthquake prediction, etc.

How much have we spent on Hubble? And Hubble doesn't really have an existential purpose. Half a billion for studying NEOs (and other targets, for sure) isn't unreasonable. Which isn't to say we /shouldn't/ be studying how to predict earthquakes, etc. Your arguments seem to work just as well against any kind of space project.

Actually, from a naked actuarial perspective, there is justification for more money to be spent on asteroid mitigation.

Consider just the city-busters: let's say we've dodged a couple of bullets over the last couple of centuries, and that the real rate of mortality from city-busters is 100,000 people per century. (After all, a direct hit in the wrong place might be able to kill 1 million people.) That equates to an annual mortality rate of 1,000 people per year. If a person's life is only worth $1M/each then it would not be a waste of money to spend $1B/year on asteroid mitigation (1,000 people/year * $1M/person = $1B/year).

Similarly for the dinosaur-killers: let's be conservative and say that my old professors Raup and Sepkowski were right about their periodic mass extinction hypothesis--that mass extinction events due to comets can be expected every 23 million years--and that we're overdue for a big collision. Probably, the global population will keep growing, so by the time the Big One hits, in round figures, the mortality rate from dinosaur-killers that would kill everybody are also on the order of 1,000 deaths per year, so spending $1B/year on a capability to deflect kilometers-wide comets coming in a hyperbolic velocities would not be unreasonable. Also, as Chris points out above, dinosaur-killers represent an existential threat--the potential for the extinction of Homo sapiens--that earthquakes and city-buster asteroids do not represent, and so arguably mitigation of dinosaur-killing comets should command a premium.

Bottom line: spending $1B/year on asteroid mitigation is not a waste of money from an actuarial perspective.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: iamlucky13 on 02/18/2013 05:36 PM
The shockwave from a supersonic fragment probably less than a meter in size probably wouldn't propagate 20+ km

I don't know why you conclude that since small bolides have been known to produce very audible sonic booms indicating that such shockwaves can readily propagate to the ground. We're talking about a highly, not marginally supersonic object which carries a lot of energy and is rapidly slowed down. That energy has to go somewhere.

Simple - because it wasn't heard on the ground. Not all bolides are. I was speculating about a single instance, not a universal principle.

And keep in mind, my speculation was already proven moot by better info from one of the forum's Russian-speaking members.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: rdale on 02/18/2013 05:51 PM
Bottom line: spending $1B/year on asteroid mitigation is not a waste of money from an actuarial perspective.

Well, if you were an actuary using actual statistics that might be true. But you aren't, and you made up the death rates, so your conclusion is completely wrong.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: iamlucky13 on 02/18/2013 06:15 PM
We got a handle on electrophonic sounds in the early 1980s when reentering Orbiters crossed the skies of Texas, and witnesses began reporting HEARING the hissing overflight in real time. 'Like a skier down a slope', one said; 'like a quiet-motor powerboat passing through a choppy lake', said another. I watched many overflights, and heard nothing until the long-after dull THUD. But it seems to really depend on lucky coincidences of specific materials near the observer -- dry pine needles, a tin wall, even frizzy hair, all seem to have worked, but I was out on an open street near empty fields.

I didn't realize until I read this second post that you were not simply talking about radio interference, but rather ordinary objects acting as crude receivers...is that right?

I'd love to read more about this if you have any sources handy.

http://www.guardian.co.uk/science/2013/feb/16/meteorite-uk

No doubt applicable to other land masses along the same latitude.

This was a thought I've pondered a couple times over the weekend. One of the first things I did after seeing a couple of the videos was look up the latitude of Chelyabinsk. With different timing, it would have come down a minimum 500 miles north of me.

Many videos seem to show that there was twin contrail from the beginning of reentry. Weird? Are the aerodynamic forces big enough to brake the meteor before contrail begins to form?

It is entirely possible, that it separated before entry due to tidal forces.

I'm sure most folks here are familiar with the hypothesis that some asteroids may effectively be "rubble piles." A related category that could explain the early divergence are called "contact binaries."

http://en.wikipedia.org/wiki/Contact_binary_%28asteroid%29


Again, nobody pays any attention to sudden very bright flash. What has happened to Duck'n'Cover  :)

I'd bet some people did hide, then after a minute or two of nothing else happening, went to look. Most people don't give the speed of sound much thought, and even if they did, few would expect something more than a couple miles (10-15 seconds) to hurt them.

I admit, I'd probably be one of the first to run to look, except I know I wouldn't be by a window because I'd run outside to get a better view...just like I did the only time I ever experienced a major earthquake...wasn't scared, just wanted to see.

I'm not a cat, but curiosity might get be killed anyways. In retrospect, though, it would at least be a good to find something solid to crouch behind and peek around.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Mongo62 on 02/18/2013 06:18 PM
I read a book years ago about the expected risks from asteroid and comet impacts.  The authors of the book had run a very large number of simulations over varying lengths of simulated time, and presented their results, together with the assumptions they had used, in the book.  I have long since forgotten its name, but the main conclusions are still clear.

As impactor size increases, the expected frequency of collisions goes down, but the expected death toll rises more quickly, so that the average death toll per year is dominated by the largest impacts.  Years with any deaths at all due to impact events are rare, but once in a while the death toll in such an event will be huge.  When all sizes of impact events are accounted for, the average expected death toll per year from impact events is surprisingly large, concentrated in a small number of rare but catastrophic events.

As far as the Chelyabinsk event in particular, it is safe to say that the city dodged a bullet.  The city was saved mass casualties by the fact that the impactor trajectory was remarkably shallow, allowing sufficient atmospheric compression to gradually build up ahead of the object for it to undergo cascading fragmentation and explosion while still at a very high altitude for a fireball of its size.  Had the object come in on a more typical angle, it would almost certainly have been much closer to ground level before exploding, resulting in a much greater level of destruction, akin to what a half-megaton nuclear airburst would be expected to cause.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: kevin-rf on 02/18/2013 06:30 PM
Haven't seen this posted yet, preliminary orbit: http://blogs.nasa.gov/cm/blog/Watch%20the%20Skies/posts/post_1361037562855.html

The Blog with more:
http://blogs.nasa.gov/cm/newui/blog/viewpostlist.jsp?blogname=Watch%20the%20Skies
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Blackstar on 02/18/2013 07:00 PM
As impactor size increases, the expected frequency of collisions goes down, but the expected death toll rises more quickly, so that the average death toll per year is dominated by the largest impacts.  Years with any deaths at all due to impact events are rare, but once in a while the death toll in such an event will be huge.  When all sizes of impact events are accounted for, the average expected death toll per year from impact events is surprisingly large, concentrated in a small number of rare but catastrophic events.

I believe that is not correct. I believe that our NRC report said something about that:

http://www.nap.edu/catalog.php?record_id=12842

I'm too lazy to look in there, but I seem to remember that although everybody focuses on the dinosaur killer size, the real threat is from the smaller, but much more numerous asteroids. They may only kill a few thousands or millions, but they're far more likely to hit.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Warren Platts on 02/18/2013 07:22 PM
Bottom line: spending $1B/year on asteroid mitigation is not a waste of money from an actuarial perspective.

Well, if you were an actuary using actual statistics that might be true. But you aren't, and you made up the death rates, so your conclusion is completely wrong.

Hey, I was only aiming for an order of magnitude, BOTE, estimate of what would be reasonable.

It's true that the mortality rates I chose are conservative, but why shouldn't they be? On the other hand, assigning $1M for the statistical value of a life is almost certainly an underestimate. For example, in 2001 the US Environmental Protection Agency (EPA) estimated the statistical value of a human life for the purposes of their cost-benefit analyses at $9.1 (http://www.nytimes.com/2011/02/17/business/economy/17regulation.html?_r=2&) each. This is nearly $12M each in today's dollars.

So we can work it out another way: assuming dinosaur-killers hit the Earth at a rate of one every 70 ma, and the population is only 7 billion, but the statistical value of a human life is $10M each, then it's still worth it to spend $1B/year on asteroid mitigation. And this is still not taking into account city busting events. Nor does it take into account the premium that humans place on especially catastrophic events like mass extinctions.

Sure there are other games you could play.

One is to take the amount we actually spend ($4M/year) and back-calculate the total worth the planet. If the risk of losing everything to a rogue comet is 1/65,000,000 per year, then $4M * 65,000,000 = $260T. To put this estimate of value in perspective, the world GDP is about $80T/year. Thus NASA and the USG place the total value of nature and civilization at only 3.25 years worth of total economic output. To state it another way, NASA and the USG implicitly place the value of a human life at only $37,142. This is certainly false.

Bottom line: we can quibble about whether we should spend $1B/year versus $100M/year on asteroid/comet mitigation, but we can be certain that the $4M/year we currently spend is unreasonably low.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: R7 on 02/18/2013 07:42 PM
Isn't it a bit difficult to put meaningful insurance value for humanity's extinction? Who would collect the cheque, from where and for what purpose? Arthur Dent/Magrathea?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: rdale on 02/18/2013 07:45 PM
but we can be certain that the $4M/year we currently spend is unreasonably low.

No, we can't be certain. If we spent what was needed to prevent every threat to any human, there'd be no money left. That's why these threats are ranked based on risk and likelihood.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 02/18/2013 07:50 PM
Bottom line: spending $1B/year on asteroid mitigation is not a waste of money from an actuarial perspective.

Well, if you were an actuary using actual statistics that might be true. But you aren't, and you made up the death rates, so your conclusion is completely wrong.

Hey, I was only aiming for an order of magnitude, BOTE, estimate of what would be reasonable.

It's true that the mortality rates I chose are conservative, but why shouldn't they be? On the other hand, assigning $1M for the statistical value of a life is almost certainly an underestimate. For example, in 2001 the US Environmental Protection Agency (EPA) estimated the statistical value of a human life for the purposes of their cost-benefit analyses at $9.1 (http://www.nytimes.com/2011/02/17/business/economy/17regulation.html?_r=2&) each. This is nearly $12M each in today's dollars.

So we can work it out another way: assuming dinosaur-killers hit the Earth at a rate of one every 70 ma, and the population is only 7 billion, but the statistical value of a human life is $10M each, then it's still worth it to spend $1B/year on asteroid mitigation. And this is still not taking into account city busting events. Nor does it take into account the premium that humans place on especially catastrophic events like mass extinctions.

Sure there are other games you could play.

One is to take the amount we actually spend ($4M/year) and back-calculate the total worth the planet. If the risk of losing everything to a rogue comet is 1/65,000,000 per year, then $4M * 65,000,000 = $260T. To put this estimate of value in perspective, the world GDP is about $80T/year. Thus NASA and the USG place the total value of nature and civilization at only 3.25 years worth of total economic output. To state it another way, NASA and the USG implicitly place the value of a human life at only $37,142. This is certainly false.

Bottom line: we can quibble about whether we should spend $1B/year versus $100M/year on asteroid/comet mitigation, but we can be certain that the $4M/year we currently spend is unreasonably low.
Agreed here.

But I think we can improve things somewhat by simply integrating it into all the other stuff NASA does instead of it being completely dedicated ONLY to asteroid mitigation. For instance, demonstrating a large SEP tug and staging it at EML1/2 (to support lunar, Martian, and/or NEO missions) would not only demonstrate the needed technology for a HSF mission to a NEO or Mars AND a large gravity tractor, but could also be put into place to provide a relatively quick emergency deflection capability.

Quick is relative here... We might be able to field a spacecraft in three years or so with an all-out effort until launch using an HLV, but if we already had a large SEP tug /with tractor capability/ out of Earth's gravity well, we could send it out almost as soon as we found out about the potential threat, even though the gravity tractor technique takes a while... This would cost way less than such an emergency effort and would be using a known-to-be-functional vehicle with lots of experience that has already traveled the riskiest portion of its mission (launch, deployment, and travel out of most of Earth's gravity well), plus would be able to be fielded and start tractoring far sooner.)

Such an ability wouldn't be free even if that's the sort of architecture we decide on for HSF anyway, but it also would provide a much more concrete justification for spending billions of dollars a year on an exploration program. And I don't think the modification itself would cost anywhere close to $1 billion/year. And it could take advantage of commercialized logistics (including possibly ISRU in the future).
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Lar on 02/18/2013 07:52 PM
but we can be certain that the $4M/year we currently spend is unreasonably low.

No, we can't be certain. If we spent what was needed to prevent every threat to any human, there'd be no money left. That's why these threats are ranked based on risk and likelihood.
We can be *reasonably* certain it's too low though. That's what actuarial analysis is all about.

Note that a lot of the other threats are either over or underspent on, IMHO anyway.  Because people go with gut feeling instead of actuarial analysis.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Warren Platts on 02/18/2013 07:57 PM
As impactor size increasesll rises more quickly, so that the average death toll per year is dominated by the largest impacts.  Years with any deaths at all due to impact events are rare, but once in a while the death toll in such an event will be huge.  When all sizes of impact events are accounted for, the average expected death toll per year from impact events is surprisingly large, concentrated in a small number of rare but catastrophic events.

I believe that is not correct. I believe that our NRC report said something about that:

http://www.nap.edu/catalog.php?record_id=12842

I'm too lazy to look in there, but I seem to remember that although everybody focuses on the dinosaur killer size, the real threat is from the smaller, but much more numerous asteroids. They may only kill a few thousands or millions, but they're far more likely to hit.

Thanks for the link.  While you are correct that the largest source is not the mass extinction dinosaur-killing objects of 10 km or greater, the peak mortality is associated with 1 to 5 kilometer asteroids that could still be expected to produce global catastrophes. These are not the mere city-buster IOW.

At any rate, on page 23, they show two sources that estimate that the annual expected mortality rate at 1,254 and 1,168 deaths per year due to asteroids and comets. (Which is very close to my own BOTE estimate of 1,000/year--yes, I admit I was right for the wrong reasons). Therefore, the amount we should be spending on asteroid mitigation is:

Optimal cost = 1200 * the statistical value of a single human life

So if one thinks that the value of a human life is $12M (EPA), then we should be spending $14.4B/year on asteroid mitigation.

If you think the value of a human life is only $120K (Russian opinion poll), then we should be spending $144M/year on asteroid mitigation.

Take your pick as you like, but no matter how you slice it, $4M/year is much too low. In effect, the current level of spending places the statistical value of a single human life at only $3,333.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 02/18/2013 08:01 PM
WISE was a primarily a science mission, for instance, but it also served to detect NEOs (and is partly why its mission was extended). WISE isn't a perfect example, but I do think that we can probably get the most bang for our buck by including NEO detection goals in any relevant science missions and relevant science goals in any NEO detection missions.

This is like how KEPLER, while primarily an exoplanet mission, is providing excellent astrometry data and data used for studying the interior of stars (using asteroseismology).
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Warren Platts on 02/18/2013 08:09 PM
WISE was a primarily a science mission, for instance, but it also served to detect NEOs (and is partly why its mission was extended). WISE isn't a perfect example, but I do think that we can probably get the most bang for our buck by including NEO detection goals in any relevant science missions and relevant science goals in any NEO detection missions.

This is like how KEPLER, while primarily an exoplanet mission, is providing excellent astrometry data and data used for studying the interior of stars (using asteroseismology).

Agreed, but an interesting question is whether the awareness raised by the Chelyabinsk event will result in fresh, new monies being appropriated for NASA. I think an actuarial justification for that can certainly be made. These monies would serve the primary purpose of asteroid risk mitigation--but would also serve other, fun,"dual-uses"! ;)
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Danderman on 02/18/2013 08:16 PM
I would imagine that a simple I/R detector in a tundra orbit would be useful in detecting incoming objects from the sunward direction. After all, if they are baking in the sun for a long time, they should be very visible to a decent i/r detector.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: JimO on 02/18/2013 09:33 PM
I didn't realize until I read this second post that you were not simply talking about radio interference, but rather ordinary objects acting as crude receivers...is that right?

I'd love to read more about this if you have any sources handy.

Did these links satisfy?

http://forum.nasaspaceflight.com/index.php?topic=31118.345
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: iamlucky13 on 02/18/2013 10:30 PM
I didn't realize until I read this second post that you were not simply talking about radio interference, but rather ordinary objects acting as crude receivers...is that right?

I'd love to read more about this if you have any sources handy.

Did these links satisfy?

http://forum.nasaspaceflight.com/index.php?topic=31118.345

Sorry...I missed noticing the previous link. Thank you.
http://web.archive.org/web/19990128124350/http://users.hunterlink.net.au/~ddcsk/

And amazingly - the shock effect is quite mild

Found another video of Korkino. But the windows were broken. The delay 89s too.  0:07 flash,  1:36 shock wave. http://www.youtube.com/watch?v=Ryd-dDi9GYs

Incredible. None of the other videos really make clear how much brighter than the morning twilight it was.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: DLR on 02/19/2013 03:58 AM
The orbits of most large NEOs are known. The real unknown are comets swooping in from the Oort Cloud. By the time we notice that a comet is on a collision course, it may already be too late to deploy something like a gravity tractor. We would need to pummel it with nukes.

First step: get rid of the space nuclear test ban.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 02/19/2013 04:05 AM
The orbits of most large NEOs are known. The real unknown are comets swooping in from the Oort Cloud. By the time we notice that a comet is on a collision course, it may already be too late to deploy something like a gravity tractor. We would need to pummel it with nukes.

First step: get rid of the space nuclear test ban.
SEP tugs can put a lot of mass on target and could be used as a good first stage for a deep-space interceptor (if it had time, it could make a sunward swoop to pick up speed, could even use a heck of an Oberth effect if the payload fired a solid near perisol on a very close pass by the Sun). To do better, we'd need nuclear-electric, which would help with HSF exploration of the outer planets (this is a late-century capability anyway... We won't be able to tackle those sort of threats for quite a while).
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Hyperion5 on 02/19/2013 04:17 AM
It had the yield of the largest warhead carried by US nuclear submarines.   Lucky that it detonated high and wide of that town.


Yeah, 500 kilotons is nothing to joke about for sure.  I believe I read it hit the atmosphere at a 20 degree angle, which was why it broke up far overhead (thank goodness).  Does anyone know what angles would have seen this meteor survive atmospheric entry and smash into the ground?  Just how much would the entry angle have had to change for us to now be marking a dark day in world history? 
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Warren Platts on 02/19/2013 04:49 AM
The orbits of most large NEOs are known. The real unknown are comets swooping in from the Oort Cloud. By the time we notice that a comet is on a collision course, it may already be too late to deploy something like a gravity tractor. We would need to pummel it with nukes.

First step: get rid of the space nuclear test ban.
SEP tugs can put a lot of mass on target and could be used as a good first stage for a deep-space interceptor (if it had time, it could make a sunward swoop to pick up speed, could even use a heck of an Oberth effect if the payload fired a solid near perisol on a very close pass by the Sun). To do better, we'd need nuclear-electric, which would help with HSF exploration of the outer planets (this is a late-century capability anyway... We won't be able to tackle those sort of threats for quite a while).

I agree with DLR. The real wild cards are the Oort cloud comets. We've already found the vast majority of large NEA's that pose a potential global catastrophe. These aren't the real threat: if they were headed for the keyhole, we would have years of heads up time to figure out something.

A comet that's barreling down on a collision course at hyperbolic velocities is a completely different animal. Not sure what it would take to dissuade such an animal, but gravity tractors are probably not it IMHO....
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 02/19/2013 05:46 AM
You didn't read what you just quoted.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: DLR on 02/19/2013 07:21 AM
The orbits of most large NEOs are known. The real unknown are comets swooping in from the Oort Cloud. By the time we notice that a comet is on a collision course, it may already be too late to deploy something like a gravity tractor. We would need to pummel it with nukes.

First step: get rid of the space nuclear test ban.
SEP tugs can put a lot of mass on target and could be used as a good first stage for a deep-space interceptor (if it had time, it could make a sunward swoop to pick up speed, could even use a heck of an Oberth effect if the payload fired a solid near perisol on a very close pass by the Sun). To do better, we'd need nuclear-electric, which would help with HSF exploration of the outer planets (this is a late-century capability anyway... We won't be able to tackle those sort of threats for quite a while).

Space-based nuclear reactors are not a late 21st-century technology. Whether one will be built and flown in the next ten to twenty years is a question of political will. In addition to comet defence it would be useful to all sorts of programmes (planetary outposts, rapid interplanetary travel, high-capability deep-space probes ...). I don't think space reactors really are a controversial issue.

The real problem is the Nuclear Test Ban Treaty. It prevents us from experimentally verifiying the effect of nuclear explosions on various types of asteroids/comets.

If you want to deflect hyperbolic comets and small, previously unknown asteroids heading towards a populated area (too little time between discovery and impact to employ a GT), nukes are the only option we have. If we want to get real about planetary defence we'll have to acknowledge this and amend the treaty.

This is quite an interesting paper:

http://www.adrc.iastate.edu/files/2011/09/2134720_wie.pdf

it would be possible to sufficiently disperse an asteroid with the same orbital and physical parameters as Apophis using a 300kt subsurface nuclear explosion up to 15 days before impact.

With only a few days lead time and a nuclear interceptor on station in orbit, the Chelyabinsk Meteor could have been dispersed into harmless fragments.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: A_M_Swallow on 02/19/2013 08:35 AM
The real problem is the Nuclear Test Ban Treaty. It prevents us from experimentally verifiying the effect of nuclear explosions on various types of asteroids/comets.
{snip}

Before we start changing treaties things like finding and docking to an asteroid can be tested using conventional explosives.  When we can steer small asteroids then we can ask permission to steer big ones.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: suncity on 02/19/2013 09:29 AM
It had the yield of the largest warhead carried by US nuclear submarines.   Lucky that it detonated high and wide of that town.


Yeah, 500 kilotons is nothing to joke about for sure.  I believe I read it hit the atmosphere at a 20 degree angle, which was why it broke up far overhead (thank goodness).  Does anyone know what angles would have seen this meteor survive atmospheric entry and smash into the ground?  Just how much would the entry angle have had to change for us to now be marking a dark day in world history? 

I understand that such a meteor will not reach the ground, independent of the entry angle. There was a nice article in Sky and Telescope about the Tunguska event explaining how they “explode” at altitude and devastate wide area with the shock wave.
If I remember correctly, Chondrite asteroid are brittle; when entering the atmosphere, they face a massive aerodynamic force, proportional to air density, on their leading side. The body of the meteor is subject to compressive stress. When the meteor reaches lower and lower altitudes, it sees higher and higher aerodynamic resistance due to increase in air density, and when the compression stress become greater then the body resistance, it breaks into pieces. The fragments in the trailing side ram forward and create a larger leading surface that further increase air resistance and give rise to the “explosion”.

This will likely happen when it reaches a certain air density/altitude, irrespective of the angle of entry. But I guess the damage on the ground will be much more concentrated if a meteor strikes at 90° and the shock wave is not spread over a long flight path.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Maciej Olesinski on 02/19/2013 10:28 AM
New compilation (just in case anyone haven't seen it yet)
liveleak.com/view?i=3b9_1361266537
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: smoliarm on 02/19/2013 11:13 AM
...
#1
By the time we notice that a comet is on a collision course, it may already be too late to deploy something like a gravity tractor.
...
#2
We would need to pummel it with nukes.
...
#3
First step: get rid of the space nuclear test ban.

#1 -- yes, that's the case to consider. But there is no reason not to try to create an EARLY warning system.

#2 -- nonsense.
Like I said before, most of meteorites are VERY fragile - naturally. This is from my personal experience, not from books. But you don't have to take my word, refer to meteorite catalogs: 1. Monica Grady; 2. V.Buchwald; 3. R.Hutchinson.

To shatter 15-meter H-chondtrity body into 1000 pieces - the classic Russian RPG-29 would be quite enough. For a guy like DA14 (50 to 100 m in diameter) - a light American armor-piercing bomb (like what they used at Midway) is sufficient.
NO nukes, all you need is 500 lbs of TNT and Lieutenant Commander McClusky.

#3 -- I strongly disagree, again.
No need to go into politics that DEEP. First thing is a detection/warning system, the space nuclear test ban is no problem here. The second thing is also different - it's a guidance system with VERY smart computer to deliver a DIRECT hit. Near miss does not work for any warhead - TNT or nuke - there is no shock wave in space.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 02/19/2013 12:14 PM
DLR: Don't read into what I'm saying. I'm saying Oort cloud objects won't be dealt with until at least the latter part of the 21st century, not that we couldn't build the tech needed earlier. To say anything else would be highly optimistic.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: JimO on 02/19/2013 12:26 PM
I posted this on a different discussion board but some readers here needed to see it, to:
-------

There are some fundamentally wrong assumptions about meteors being used here as the basis for some wild time-wasting speculations.

Mainly this: claiming that the 'trail' was the result of material from the object. Or 'smoke'. Or dust, or condensation.

Actually, although occasionally tinged with combustion products, the main white trail of fireball meteors actually  is ionized atmospheric constituents. Torn-apart oxygen and nitrogen molecules, ionized by the extreme heat of the compressive shock wave

So naturally the trail can wax and wane and vanish purely as a function of the quickly varying speed and area of the entering object.

Nothing better illustrates this than the space shuttle, which left magnificent trails across the night skies of Texas on many entries to Florida landings in the 1980s and 1990s, and of course, sadly, over East Texas on February 1, 2003. With my family, I observed more than half a dozen such overflights with my own eyes.

And it left these trails without losing ANY material, NO chemical or dust or smoke coming off. JUST tearing apart the atmosphere as it passed, leaving a white trail that gradually dissipated over a period of minutes as the atoms rejoined into N2 and O2 molecules.

JUST LIKE over Chelyabinsk.

See a compilation of eyewitness descriptions of such a space shuttle entry, here:
http://www.jamesoberg.com/96mar-sts72_entry.pdf

I hope this helps attain a proper understanding of, and interpretation of, the Chelyabinsk meteor trail and its implications.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: kevin-rf on 02/19/2013 12:43 PM
Honestly, we are talking about multiple different threats.

NEO's over 1km >95% identified, mitigation possible without nukes.
NEO's over 100m 5% identified, better search (IR space based, ect) needed, mitigation possible on known objects without nukes, objects identified late... pucker factor.

NEO's < 100m, while we tract asteroids down to 5 meters, they are outside of what we can reliably detect years in advance. They usually don't make it to the ground, but the airburst is such that the higher up it occurs the better off we are. I really wonder if hitting it with something like an ICBM mid course interceptor could be used to crack it so it breaks up at a higher altitude. We have to assume late detection, so we would have to repoint the search radars to point upwards and have a very short chain for firing. If we detect a rock moving 30 km a sec at an altitude of 600 km, you only have 20 seconds to get the interceptor on location (not possible). You need detection that gives you some time measured in multiple minutes. An hours notice requires you looking out beyond GSO with very big radars.

Personally I think a multi-pronged approach is needed.

Large object (>100m) dedicated IR search and multi-year mitigation technology.
Small objects (5m - 50m) late detection with giant radars that don't exist and attempt to crack them so they break up higher through the use of an interceptor.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: ChileVerde on 02/19/2013 02:04 PM

Quote
http://science.slashdot.org/story/09/06/22/1625254/us-military-blocks-data-on-incoming-meteors
http://blogs.nature.com/news/2009/07/post_30.html
http://www.nature.com/news/2009/090612/full/459897a.html
http://www.space.com/6927-military-seeks-common-ground-scientists-fireball-data-flap.html

Current news about this:

Quote
http://www.space.com/19846-russian-meteor-fallout-military-satellites.html

Russian Meteor Fallout: Military Satellite Data Should Be Shared
by Leonard David, SPACE.com’s Space Insider Columnist
Date: 18 February 2013 Time: 09:03 AM ET

 Piecing together the true nature of the meteor that detonated over Russia would benefit by observations likely gleaned by U.S. military spacecraft.

But for several years, that data has been stamped classified and not made available to the scientific community that study near-Earth objects (NEOs) and any potential hazard to Earth from these celestial interlopers.

In the wake of the Russian meteor explosion, there is a renewed call to make data gathered by both space systems and ground networks speedily available to scientists.

<considerable snip>
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: R7 on 02/19/2013 02:27 PM
To shatter 15-meter H-chondtrity body into 1000 pieces - the classic Russian RPG-29 would be quite enough. For a guy like DA14 (50 to 100 m in diameter) - a light American armor-piercing bomb (like what they used at Midway) is sufficient.
NO nukes, all you need is 500 lbs of TNT and Lieutenant Commander McClusky.

Corollary: you don't need explosives at all, just an impactor (hollow point, not AP ;) ). Kg of TNT = ~4.2MJ, kg of anything at 20km/s = 200MJ.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: smoliarm on 02/19/2013 04:18 PM
To shatter 15-meter H-chondtrity body into 1000 pieces - the classic Russian RPG-29 would be quite enough. For a guy like DA14 (50 to 100 m in diameter) - a light American armor-piercing bomb (like what they used at Midway) is sufficient.
NO nukes, all you need is 500 lbs of TNT and Lieutenant Commander McClusky.

Corollary: you don't need explosives at all, just an impactor (hollow point, not AP ;) ). Kg of TNT = ~4.2MJ, kg of anything at 20km/s = 200MJ.

Nice idea, especially if most of these 20km/s come from asteroid itself.
BTW, "hollow point" will work with chondrites, they are ~ 85% of all meteorites, but it won't work with iron meteorites - they are about 10%. Here we would need AP, perhaps depleted uranium tip ;)
But the remaining 5% - basaltic achondrites - they are basalts indeed, dense and robust. For them you need HE bunker-buster ammunition.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 02/19/2013 04:53 PM
Or, how about a counter-orbiting impactor, giving a relative velocity of 60km/s, far beyond chemical explosives. Could be accelerated slowly using very high-Isp ion thrusters, then kept in an heliocentric orbit ready to be commanded to intercept. (You'd need several of these so you could intercept within a month of command.)
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Blackstar on 02/19/2013 05:08 PM
Or, how about a counter-orbiting impactor, giving a relative velocity of 60km/s, far beyond chemical explosives. Could be accelerated slowly using very high-Isp ion thrusters, then kept in an heliocentric orbit ready to be commanded to intercept. (You'd need several of these so you could intercept within a month of command.)

I know that it's fun to speculate wildly, but there are some sources you could read out there about this. I've worked with the PI on the Deep Impact mission and he said that impacting that comet, which was 100 km wide, at 10 km/s, was very difficult to do. So trying to hit something even smaller at six times the relative velocity might be a little harder.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: jgoldader on 02/19/2013 05:10 PM
It's unfortunate that Shoemaker-Levy/9 didn't really focus the necessary amount of attention on the danger of impacts.  One would think that 1000-km mushroom clouds would make even Congress pay attention! 

But asteroid-hunting isn't sexy enough.  It has to compete with every other interest group in astronomy for funding.  Frankly, it does us no good at all if NASA's planned WFIRST telescope discovers the secrets of dark energy a week before we go extinct from a modern-day K/T event.

The really scary asteroids are ones which, like 2012 DA14, spend almost all their time interior to Earth's orbit.  These are best found with a space-based telescope that can peer between the orbits of Earth and Venus.  As of now, we have no such telescope.  The B612 Sentinel telescope is on the right track, but it's not cheap; time to prioritize.

Jeff
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: JimO on 02/19/2013 05:16 PM
I know that it's fun to speculate wildly, but there are some sources you could read out there about this. I've worked with the PI on the Deep Impact mission and he said that impacting that comet, which was 100 km wide, at 10 km/s, was very difficult to do. So trying to hit something even smaller at six times the relative velocity might be a little harder. 

I want to stronlgy underscore Blackstar's skepticism here,  based on a fundamental principle of flight control.

As range to impact decreases, knowledge of 'relative state' improves and uncertainty shrinks.

But with shorter and shorter flight segments to impact, the time for control actions to MOVE the aim point decreases, and so the net result of steering thrusting gets smaller and smaller.

For all control modes I've seen proposed for moving asteroids, in the terminal phase the uncertainty ellipse shrinks so quickly that the steering capability location ellipse no longer overlaps the aim point and there no longer is enough force to push the aim point back inside the location ellipse before fly-past.

I tried to tell Carl Sagan this, that his fear of a madman hijacking an asteroid defense system and deliberately impacting Earth, was a fantasy. A system that is designed to push one large uncertainty ellipse -- the aiM point -- safely OUTSIDE another huge uncertainty ellipse -- the Earth location -- is easy to design and control. The opposite is NOT.

Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: smoliarm on 02/19/2013 05:42 PM
I posted this on a different discussion board but some readers here needed to see it, to:
-------

There are some fundamentally wrong assumptions about meteors being used here as the basis for some wild time-wasting speculations.

Mainly this: claiming that the 'trail' was the result of material from the object. Or 'smoke'. Or dust, or condensation.

Actually, although occasionally tinged with combustion products, the main white trail of fireball meteors actually  is ionized atmospheric constituents. Torn-apart oxygen and nitrogen molecules, ionized by the extreme heat of the compressive shock wave

So naturally the trail can wax and wane and vanish purely as a function of the quickly varying speed and area of the entering object.

Nothing better illustrates this than the space shuttle, which left magnificent trails across the night skies of Texas on many entries to Florida landings in the 1980s and 1990s, and of course, sadly, over East Texas on February 1, 2003. With my family, I observed more than half a dozen such overflights with my own eyes.

And it left these trails without losing ANY material, NO chemical or dust or smoke coming off. JUST tearing apart the atmosphere as it passed, leaving a white trail that gradually dissipated over a period of minutes as the atoms rejoined into N2 and O2 molecules.

JUST LIKE over Chelyabinsk.

See a compilation of eyewitness descriptions of such a space shuttle entry, here:
http://www.jamesoberg.com/96mar-sts72_entry.pdf

I hope this helps attain a proper understanding of, and interpretation of, the Chelyabinsk meteor trail and its implications.


Jim, you are not exactly right.
What you say about Space Shuttle trail is 100% true. The same applies to the part of meteorite trail BEFORE the bright glow begins. After that it is a different story.
Main constituents of this type of meteorite are silica, olivine, troilite (FeS), and iron-nickel metal. At plasma temperatures they all are volatile, as volatile as water ice is at 500 °C. This is why it all ends in explosion.
The bright glow marks the beginning of ablation, at this point contrail has some part of true smoke in it, the smoke proportion goes up as meteor goes down :)
Now exciting part, the explosion - iron, nickel, sulfur, and silica vaporized at say 6000 °K and compressed to hell-knows-what-pressure -- expand rapidly. Pressure drops -> temperature drops -> everything condenses to solid -> VACUUM. This creates very peculiar and violent shock wave, and leaves behind a cloud of tiny particles of amorphous iron, nickel, sulfur, and silica. The first three substances are pyrophorus, they react with oxygen on contact releasing even more energy. And that's what they do when the air mixes into this newly formed cloud.
This is what we see on the second photo.
The photographer got lucky - he managed to make a shot right before the main flash (first frame),
and one more, few seconds later - the second frame. On this one you can see red glow, marked with blue arrow. That's exactly it:
2Fe + O2 = 2FeO (plus a lot of heat)
The third frame was made hours later, and the author noted that the upper part of the trail disappeared fairly soon while the lower part stayed for the whole day.

The original photos page:
http://marateaman.livejournal.com/27649.html
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: AJW on 02/19/2013 07:21 PM
It would seem that increased study of transient lunar phenomena would provide great insight into the actual size and regularity of impacts here on Earth.  Ocean strikes can leave little record, and nature can hide a Tunguska event in less than a century. Twenty years after Tanguska, in 1927, locals still did not want to discuss the event because they believed that they had been visited and cursed by an angry god.

http://science.nasa.gov/science-news/science-at-nasa/2008/30jun_tunguska/

The report by Canterbury monks in 1178 is worth reading as it describes a series of a dozen surface explosions on the moon as well as ejecta and is reminiscent of the hits by the fragments of Shoemaker-Levy 9. 

"There was a bright new moon, and as usual in that phase its horns were tilted toward the east; and suddenly the upper horn split in two. From the midpoint of this division a flaming torch sprang up, spewing out, over a considerable distance, fire, hot coals, and sparks. Meanwhile the body of the moon which was below writhed, as it were, in anxiety, and, to put it in the words of those who reported it to me and saw it with their own eyes, the moon throbbed like a wounded snake. Afterwards it resumed its proper state. This phenomenon was repeated a dozen times or more, the flame assuming various twisting shapes at random and then returning to normal. Then after these transformations the moon from horn to horn, that is along its whole length, took on a blackish appearance."

Increased study of TLP can start today and could give us a far more accurate view of the frequency, size, and the actual risks involved.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 02/19/2013 07:28 PM
Or, how about a counter-orbiting impactor, giving a relative velocity of 60km/s, far beyond chemical explosives. Could be accelerated slowly using very high-Isp ion thrusters, then kept in an heliocentric orbit ready to be commanded to intercept. (You'd need several of these so you could intercept within a month of command.)

I know that it's fun to speculate wildly, but there are some sources you could read out there about this. I've worked with the PI on the Deep Impact mission and he said that impacting that comet, which was 100 km wide, at 10 km/s, was very difficult to do. So trying to hit something even smaller at six times the relative velocity might be a little harder.
Indeed, this wouldn't be a near-term capability and it'd be expensive. Sorry for letting the speculation go rampant.

I do want to read the report you linked to, by the way. Thanks for it.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 02/19/2013 07:42 PM
I know that it's fun to speculate wildly, but there are some sources you could read out there about this. I've worked with the PI on the Deep Impact mission and he said that impacting that comet, which was 100 km wide, at 10 km/s, was very difficult to do. So trying to hit something even smaller at six times the relative velocity might be a little harder. 

I want to stronlgy underscore Blackstar's skepticism here,  based on a fundamental principle of flight control.

As range to impact decreases, knowledge of 'relative state' improves and uncertainty shrinks.

But with shorter and shorter flight segments to impact, the time for control actions to MOVE the aim point decreases, and so the net result of steering thrusting gets smaller and smaller.

For all control modes I've seen proposed for moving asteroids, in the terminal phase the uncertainty ellipse shrinks so quickly that the steering capability location ellipse no longer overlaps the aim point and there no longer is enough force to push the aim point back inside the location ellipse before fly-past.

I tried to tell Carl Sagan this, that his fear of a madman hijacking an asteroid defense system and deliberately impacting Earth, was a fantasy. A system that is designed to push one large uncertainty ellipse -- the air point -- safely OUTSIDE another huge uncertainty ellipse -- the Earth location -- is easy to design and control. The opposite is NOT.


Oh, I certainly believe you. This is a similar problem to anti-ballistic-missile defense except at a greater scale.

But I consider this a slightly less fundamental problem (than the fundamental energy and momentum constraints) since the uncertainty ellipse can be attacked using better remote sensing, reducing divert thrust requirements. I still agree it makes aiming an asteroid /towards/ the Earth (especially a specific part of Earth) more difficult. Given the choice, gravity tractor should be chosen whenever it is viable since it is a more precise method and can direct the asteroid carefully as to avoid any secondary keyholes.

In every single scenario, the situation is improved remarkably with having better remote sensing. Knowing the position, composition, structure, velocity, mass, rotation, etc. of a potentially hazardous object as early as possible and as accurate as possible is incredibly important and knowing much sooner and more accurately can reduce your deflection requirements by orders of magnitude (importantly, if you can deflect the object before it makes a close pass of a large gravity well, you have an enormous lever arm, reducing your divert requirements by perhaps 4 or 5 orders of magnitude). Thus, at LEAST a comparable amount of money should be spent on improving remote sensing and recon as should be spent on any deflection capability.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: JimO on 02/19/2013 08:00 PM
Quote from: smoliarm Jim, you are not exactly right. [/quote

Many's the time I have been 'not exactly right', but THIS time, i was plain wrong, as several friends advised me. This feels better.

 Thanks, let's follow this to a better understanding of recovery of particles,m as well as swabs off of clean surfaces. Could somebody shovel up several square yards of snow, melt it down, and expect to find recoverable particulates?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Targeteer on 02/19/2013 11:43 PM
NBC nightly news just ran a story detailing why so many Russians have those dash cams.

Video of a tank crossing a highway and a car being hit by a tire from a crashed aircraft were interesting...
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: indaco1 on 02/20/2013 01:07 AM
Just how much would the entry angle have had to change for us to now be marking a dark day in world history? 

I understand that such a meteor will not reach the ground, independent of the entry angle.


I'm not certain the parameters I used, but just to have an idea I used the calculator at http://impact.ese.ic.ac.uk/ImpactEffects/


tetha=7°    burst at 30km
http://impact.ese.ic.ac.uk/cgi-bin/crater.cgi?dist=5&distanceUnits=1&diam=17&diameterUnits=1&pdens=5000&pdens_select=0&vel=17&velocityUnits=1&theta=7&wdepth=&wdepthUnits=1&tdens=2500

tetha=90°  burst at 11.9 km so it still it will not touch the ground.
http://impact.ese.ic.ac.uk/cgi-bin/crater.cgi?dist=5&distanceUnits=1&diam=17&diameterUnits=1&pdens=5000&pdens_select=0&vel=17&velocityUnits=1&theta=90&wdepth=&wdepthUnits=1&tdens=2500

If some parameter of the shock wave was inversely proportional to square of distance (I don't know),  at a distance of 10km it could be about 10 times more than at 30km. I repeat this is a guess, I really don't know if the physics of shock waves works this way.

Furthermore at 90° I suppose energy release will be much more rapid and "explosive", generating a more destructive shock wave regardless the distance.

Not nice a thing like this over a million people city like Chelyabinsk.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 02/20/2013 03:32 AM
Also, thicker air at 11km would transport the shock wave much better.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: R7 on 02/20/2013 12:35 PM
Did Deep Impact have some kind of active autonomous terminal guidance or was it done from Earth? Just wondering what could be done to address the targeting problem of specialized asteroid kill vehicle.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: JohnFornaro on 02/20/2013 02:18 PM
... There was a nice article in Sky and Telescope about the Tunguska event explaining how they “explode” at altitude and devastate wide area with the shock wave...

So... it was the shock wave which flattened all those trees shown in the few fotos of the impact zone?

Remember that the shock wave from Mount St. Helens flattened a huge forest when it erupted.

As range to impact decreases, knowledge of 'relative state' improves and uncertainty shrinks.

But with shorter and shorter flight segments to impact, the time for control actions to MOVE the aim point decreases, and so the net result of steering thrusting gets smaller and smaller.... yada yada...

Which proves that nobody "allowed" this event to happen.  But one thing that is clear is that any protection system hinges upon accurate knowledge of asteroid trajectories.

If it is thought that a tiny "gravity tractor" can displace an orbit, then it must be acknowledged that each asteroid out there is a gravity tractor itself. Each individual orbit is subject to so many perturbrations that it seems virtually impossible to make accurate predictions, particularly which city would be hit at which angle.

Since it takes one "unknown unknown" to fly in at some random orbit, the best laid plans of mice and asteroid predictors are hard to state with any certainty.  One prediction that one will hit NYC at 9:00 AM on Thursday, prompting a timely evacuation, will doom any further hunting, should the prediction prove to be false.

The report by Canterbury monks in 1178 is worth reading as it describes a series of a dozen surface explosions on the moon as well as ejecta and is reminiscent of the hits by the fragments of Shoemaker-Levy 9.

Fascinating report.  Is it now known where this hit took place?  Would it have left a visible "new" scar?  Somebody ask Paul Spudis.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 02/20/2013 02:20 PM
...

If it is thought that a tiny "gravity tractor" can displace an orbit, then it must be acknowledged that each asteroid out there is a gravity tractor itself. ...
Inverse square law.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: JohnFornaro on 02/20/2013 03:16 PM
...

If it is thought that a tiny "gravity tractor" can displace an orbit, then it must be acknowledged that each asteroid out there is a gravity tractor itself. ...
Inverse square law.

Which is the acknowledgement I mentioned.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: go4mars on 02/20/2013 04:04 PM
So... it was the shock wave which flattened all those trees shown in the few fotos of the impact zone?

Remember that the shock wave from Mount St. Helens flattened a huge forest when it erupted.
The area flattened was very large.  IIRC, it is believed, partially based on fragments recovered from trees that were killed around there, that it was a relatively fluffy volatile-rich bollide.  Although there is a small lake that people wonder about its provenance, a lot of it broke apart high in the atmosphere, and most of the devastation was due to a giant supersonic plasma ball, as opposed to a "kathunk---sploooosh" on the surface. 

There is some speculation, which is still undergoing debate, that the Younger Dryas was punctuated by one or more North American impacts of regional affect.  Just south of one of the Great Lakes, there is what looks like a melt-path, clearly viewable on google earth satallite imagery, where it sorta looks like a bunch of the native rock there was flash-melted then flowed.  Also, there are a bunch of small lakes/depressions across the mid-east of North America that are perhaps impact related.  IIRC, there was even some shocked quartz found related to Younger Dryas impacts, and some regional char layers here and there.  Some suggest that an alternate theory for the giant floods that have been documented during the last glaciation, is flash-melting of enormous volumes of continental ice sheet, as opposed to ice bridges/plugs letting go.  There is debate about the conclusions and scale, but I think that in a couple decades the consensus will tip toward the impact hypothesis.   

Burckle crater gives an idea of why I like living at 3600 feet elevation, though I haven't built a buried monolithic dome home yet.  :)
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: JohnFornaro on 02/20/2013 04:39 PM
Burckle crater gives an idea of why I like living at 3600 feet elevation, though I haven't built a buried monolithic dome home yet.

If you need an architect, I'm your guy.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: go4mars on 02/20/2013 05:28 PM
Burckle crater gives an idea of why I like living at 3600 feet elevation, though I haven't built a buried monolithic dome home yet.

If you need an architect, I'm your guy.
I'll PM you when the time comes.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: AJW on 02/20/2013 05:28 PM

The report by Canterbury monks in 1178 is worth reading as it describes a series of a dozen surface explosions on the moon as well as ejecta and is reminiscent of the hits by the fragments of Shoemaker-Levy 9.

Fascinating report.  Is it now known where this hit took place?  Would it have left a visible "new" scar?  Somebody ask Paul Spudis.


There was conjecture in 1976 that this led to the formation of the 22km Giordano Bruno crater.  Others postulate that an impact of that size would have kicked up enough debris to cause a week-long meteor storm here on Earth.  I would approach this from a different direction and ask what size explosion would have been visible as described.  As an example, the 100kt Sedan nuclear test left a crater only 390 meters across.  The 15 megaton Castle Bravo blast left a 2km crater, so a Canterbury impact crater could be quite small compared to Giordano Bruno.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: ugordan on 02/20/2013 05:32 PM
Castle Bravo was a near-surface detonation that didn't really couple energy strongly to the ground (that crater was also very shallow) and should not really be compared to asteroid impacts that couple all of their kinetic energy to the ground. Sedan was buried pretty deeply underground but I suppose comparing impacts to it makes more sense.

Seeing something on the Moon undoubtedly would require much more energy than Bravo and I can see why some would postulate meteor storms caused by such an event.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: AJW on 02/20/2013 07:01 PM
A quick check shows that on June 18, 1178, there was a waxing moon less than 6% full, so any bright flash would likely be against a mostly dark surface.  Reports from Trinity were that it was brighter than daylight and lit up the surrounding mountains for a number of seconds.  That was 20kt.  Little Boy at 16kt was compared to twice the brightness of the sun for 10-15 seconds at six miles.  Do this on the unlit moon on a dark night twelve times in a row and someone here might take notice.  Chelyabinsk at ~500kt might be pretty effective as well.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: ugordan on 02/20/2013 07:20 PM
The Moon has no atmosphere. Those events you describe were bright as hell because they produced large volumes of incandescent air. That's one corner case, the other one might be the Sedan test which you mentioned. Glowing vaporized rock, but hardly blinding light.

Detonate those same weapons in a vacuum and you'd maybe get an instantaneous and short flash and that's it. Detonate on a surface with a hard vacuum above and you'd get a bright, but relatively shortlived flash of vaporized rock/regolith. I wonder if something in the kiloton range would even be noticeable to someone who wasn't looking directly at the Moon at the right moment. It's possible the ejected plume coming into sunlight (if lighting conditions were right) would be more noticeable than the initial flash.

Now, something that could create a 20 km crater, that would probably be a very different story...
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: iamlucky13 on 02/20/2013 07:33 PM

...

If it is thought that a tiny "gravity tractor" can displace an orbit, then it must be acknowledged that each asteroid out there is a gravity tractor itself. ...

As you would guess, the achievable precision increases the closer to impact (fewer remaining perturbations) you get. Not to mention, most interactions aside from the sun, moon, earth, etc, are so small as to be less significant than the margin of error in the observations used to calculate the orbit.

Hence why when 99942 Apophis was discovered, we were talking about whether or not it in 25 years it would hit a mere 1/2 mile wide "keyhole" that would swing it into an impact 6 years after that.

That itself is a result of several years worth of observations spanning multiple orbits, so it's at the high end of the achievable accuracy, but the point is, with enough motivation, we should be able to get a pretty decent idea ahead of time what region an asteroid will hit, if we find a threat ahead of time.

That is in contrast to the more difficult task of figuring out where an object in orbit will come down when it decays, because varying atmospheric drag (and an extremely, extremely shallow entry angle) add a lot of downrange uncertainty.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: JohnFornaro on 02/20/2013 07:38 PM

...

If it is thought that a tiny "gravity tractor" can displace an orbit, then it must be acknowledged that each asteroid out there is a gravity tractor itself. ...

As you would guess, the achievable precision increases the closer to impact (fewer remaining perturbations) you get. ...

Yahbut:

As range to impact decreases, knowledge of 'relative state' improves and uncertainty shrinks.

But with shorter and shorter flight segments to impact, the time for control actions to MOVE the aim point decreases, and so the net result of steering thrusting gets smaller and smaller.... yada yada...

You know precisely where to hit, but you have to wait for the last moment.  Impactors only, it would appear.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: AJW on 02/20/2013 10:31 PM
Came across this at http://science.nasa.gov/science-news/science-at-nasa/2006/13jun_lunarsporadic/

June 13, 2006: There's a new crater on the Moon. It's about 14 meters wide, 3 meters deep and precisely one month, eleven days old.
NASA astronomers watched it form: "On May 2, 2006, a meteoroid hit the Moon's Sea of Clouds (Mare Nubium) with 17 billion joules of kinetic energy, that's about the same as 4 tons of TNT," says Bill Cooke, the head of NASA's Meteoroid Environment Office in Huntsville, AL. "The impact created a bright fireball which we video-recorded using a 10-inch telescope."...  "It was a space rock about 10 inches (25 cm) wide traveling 85,000 mph (38 km/s)," he says.

Now we can at least do some apple to apple comparisons.

I had also wondered about lunar records of seismic hits.  The Chelyabinsk blast was recorded as Magnitude 4.  Similar hits on the Moon should give us more detail, but the seismometers there were turned off in 1977.

"Here's what's interesting," says Cooke. "Of some 12,000 events recorded by the seismometers, less than half have been explained by known phenomena. There are thousands of tremors caused by ... no one knows what."  He has a hunch: "Many of them may be meteoroid impacts."

http://science.nasa.gov/science-news/science-at-nasa/2006/28apr_skyisfalling/

Having a visual record of impacts to compare with seismic records certainly would add to the existing data.  Curious why the seismographs were turned off.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: catdlr on 02/21/2013 12:56 AM
Russian Meteor Produces Largest Infrasonic Waves Recorded | Video

Published on Feb 20, 2013
Infrasound, or extremely low frequency sound waves, from the meteor that broke up over Russia's Ural mountains were some of the largest ever recorded by the CTBTO's network of infrasound stations.

http://www.youtube.com/watch?v=BBdwC9eY-AM
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: rickl on 02/21/2013 05:51 AM
The report by Canterbury monks in 1178 is worth reading as it describes a series of a dozen surface explosions on the moon as well as ejecta and is reminiscent of the hits by the fragments of Shoemaker-Levy 9. 

"There was a bright new moon, and as usual in that phase its horns were tilted toward the east; and suddenly the upper horn split in two. From the midpoint of this division a flaming torch sprang up, spewing out, over a considerable distance, fire, hot coals, and sparks. Meanwhile the body of the moon which was below writhed, as it were, in anxiety, and, to put it in the words of those who reported it to me and saw it with their own eyes, the moon throbbed like a wounded snake. Afterwards it resumed its proper state. This phenomenon was repeated a dozen times or more, the flame assuming various twisting shapes at random and then returning to normal. Then after these transformations the moon from horn to horn, that is along its whole length, took on a blackish appearance."

I remember first hearing about that in the late 1970s, but re-reading it today, I'm inclined to think it may have been some kind of atmospheric phenomenon.  The new moon is close to the horizon and is subject to atmospheric distortion.  It seems to me that it would take an enormous impact to make the moon "writhe" and "throb".  Even the "coals" and "sparks" might be explained by a breaking up of the moon's image caused by atmospheric effects.

(Of course, it would be ironic if it turned out that the weird atmospheric effects were caused by an Earth impact somewhere.   :D)

There is some speculation, which is still undergoing debate, that the Younger Dryas was punctuated by one or more North American impacts of regional affect.  Just south of one of the Great Lakes, there is what looks like a melt-path, clearly viewable on google earth satallite imagery, where it sorta looks like a bunch of the native rock there was flash-melted then flowed.  Also, there are a bunch of small lakes/depressions across the mid-east of North America that are perhaps impact related.  IIRC, there was even some shocked quartz found related to Younger Dryas impacts, and some regional char layers here and there.  Some suggest that an alternate theory for the giant floods that have been documented during the last glaciation, is flash-melting of enormous volumes of continental ice sheet, as opposed to ice bridges/plugs letting go.

I'm very interested in this theory, and several years ago I read that some Indians in eastern Canada have a legend that there was a great fire in the sky, and the only people who survived were those who jumped into bodies of water until the fire passed.  Afterwards they emerged to find widespread devastation.  Sadly, I don't have a source for this, although I've tried to search for it.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Hyperion5 on 02/21/2013 06:18 AM
For awhile, I was wondering how Russians were staying so calm driving their cars while this meteor lit up the sky.  Never mind the panicky schoolkids, here's why we weren't hearing many curses about a meteor in all those car dash videos.  Jon Stewart explains:

http://www.latimes.com/entertainment/tv/showtracker/la-et-st-russia-meteor-daily-show-jon-stewart-20130220,0,1581167.story

Watch the video.  It's an instant classic.   :D ;D
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Archibald on 02/21/2013 07:58 AM
For awhile, I was wondering how Russians were staying so calm driving their cars while this meteor lit up the sky.  Never mind the panicky schoolkids, here's why we weren't hearing many curses about a meteor in all those car dash videos.  Jon Stewart explains:

http://www.latimes.com/entertainment/tv/showtracker/la-et-st-russia-meteor-daily-show-jon-stewart-20130220,0,1581167.story

Watch the video.  It's an instant classic.   :D ;D

That was hilarious and made my day, thank you very much.  ;D
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: 360-180 on 02/21/2013 08:49 AM
For awhile, I was wondering how Russians were staying so calm driving their cars while this meteor lit up the sky. 
Chelyabinsk guys in Russia have a reputation for the most harsh. ;D
Type in a search engine "Суровые челябинские мужики настолько суровые, что" means "Harsh Chelyabinsk men are so harsh that" ;D

"Harsh Chelyabinsk men are so harsh that the fish jammed (concussied) by  meteorites" 
"Chelyabinsk residents are so severe that instead of snow in winter they are falling meteorites"
excuse my poor English
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: aquanaut99 on 02/21/2013 11:51 AM
For awhile, I was wondering how Russians were staying so calm driving their cars while this meteor lit up the sky.  Never mind the panicky schoolkids, here's why we weren't hearing many curses about a meteor in all those car dash videos.  Jon Stewart explains:

http://www.latimes.com/entertainment/tv/showtracker/la-et-st-russia-meteor-daily-show-jon-stewart-20130220,0,1581167.story

Watch the video.  It's an instant classic.   :D ;D

Awesome! I almost spilled my morning coffee watching that!
I will never again complain about bad drivers over here after that!
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: jcm on 02/21/2013 12:27 PM
For awhile, I was wondering how Russians were staying so calm driving their cars while this meteor lit up the sky. 
Chelyabinsk guys in Russia have a reputation for the most harsh. ;D
Type in a search engine "Суровые челябинские мужики настолько суровые, что" means "Harsh Chelyabinsk men are so harsh that" ;D

"Harsh Chelyabinsk men are so harsh that the fish jammed (concussied) by  meteorites" 
"Chelyabinsk residents are so severe that instead of snow in winter they are falling meteorites"
excuse my poor English


A few I understood:

Chelyabinsk guys are so tough, traffic cops bribe them.

Chelyabinsk programmers are so tough that they think
programming in assembler is a luxury -
they manually magnetize hard disk sectors.

Chelyabinsk vodka is so tough that it was banned as WMD
in 190 countries.

Chelyabinsk woodpeckers are so tough, they hollowed out
2 metro stations.

Chelyabinsk guys are so tough they steal Gypsy children.

etc.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: R7 on 02/21/2013 01:17 PM
"In Chelyabinsk you hit the meteorite."
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Prober on 02/21/2013 02:48 PM
Can't believe some of the thinking.
 
You couldn't want to blast and create a debris field.
 
If its so large a rock in space it will destroy all life on earth that's one matter.
 
 
 
 
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: kevin-rf on 02/21/2013 03:06 PM
You couldn't want to blast and create a debris field.

The advantage of cracking an incoming meteor is the smaller the bits, the higher up the bits breakup. Chelyabinsk was ~500 kt at ~30km, if it had been 500 kt at a couple of km the outcome would have been much more tragic. You still will have the same amount of energy released, it just be at a higher altitude. An end game that attempts to crack them just before entry could save lives from the 10m plus objects.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: douglas100 on 02/21/2013 03:31 PM

If its so large a rock in space it will destroy all life on earth that's one matter.

This planet has been bombarded by objects of different sizes for billions of years. Life is still here. Humans, that's a different matter...
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 02/21/2013 05:03 PM

If its so large a rock in space it will destroy all life on earth that's one matter.

This planet has been bombarded by objects of different sizes for billions of years. Life is still here. Humans, that's a different matter...
Not entirely true, actually. I'm actually not entirely sure life would've survived the impact that created the Moon. On Earth itself, everything would be high enough temperature to be sterilized. Life would've only survived by being blown out into space, but then that's not "life on Earth" any longer.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: douglas100 on 02/21/2013 11:02 PM

Not entirely true, actually.

What's not entirely true? I said that life is still here. I think you'll find that is entirely true.  :)

The other point, that the impact of a Moon sized object could sterilize the Earth is probably true. But it obviously hasn't happened since life has arisen on this planet. The chance of that happening before the Sun becomes hot enough to destroy life on Earth is very small indeed. (There is apparently a few percent chance that the orbits of Mars or Mercury could become chaotic enough in four or five billions years time to cause planetary collisions.)

We don't have to worry about collisions of that magnitude. Impacts of objects the size of the Chelyabinsk meteor and up to kilometers in scale, we do, of course, have to worry about.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Comga on 02/21/2013 11:04 PM
Or, how about a counter-orbiting impactor, giving a relative velocity of 60km/s, far beyond chemical explosives. Could be accelerated slowly using very high-Isp ion thrusters, then kept in an heliocentric orbit ready to be commanded to intercept. (You'd need several of these so you could intercept within a month of command.)

I know that it's fun to speculate wildly, but there are some sources you could read out there about this. I've worked with the PI on the Deep Impact mission and he said that impacting that comet, which was 100 km wide, at 10 km/s, was very difficult to do. So trying to hit something even smaller at six times the relative velocity might be a little harder.

Nit to pick: The nucelus of the Temple 1 cometary target for Deep Impact was much smaller than 100 km, more like 6 km

Name             Dimensions    Density   Mass 
                     km              g/cm3      kg             
Halley's Comet 15 × 8 × 8   0.6       3×10^14
Tempel 1         7.6×4.9 (https://planetary.s3.amazonaws.com/assets/images/9-small-bodies/2012/20121218_asteroids_comets_sc_0-000-100_2012_color_brightened.png?__utma=113505944.1071060582.1355949633.1355949633.1361491129.2&__utmb=113505944.11.9.1361491227458&__utmc=113505944&__utmx=-&__utmz=113505944.1361491129.2.2.utmcsr=forum.nasaspaceflight.com|utmccn=(referral)|utmcmd=referral|utmcct=/index.php&__utmv=-&__utmk=26867325)       0.62   7.9×10^13
19P/Borrelly     8×4×4        0.3       2×10^13
81P/Wild         5.5×4.0×3.3 0.6  ] 2.3×10^13
(from a well referenced Wikipedia article (http://en.wikipedia.org/wiki/Comet_nucleus))

And Deep Impact did mange to hit close to the center of the sunlit area on the side of the fly-by, and was equiped to do so even if the nucelus had been irregular, rather than lumpy but nearly spherical.  Also, the impact was done with a very simple battery powered spacecraft using, IIRC, two lateral thrusters and a couple of roll control thrusters.  If the mission is destruction of a threatening comet or asteroid the top priority would no longer be having the majority of the spacecraft survive to send back data. 
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Comga on 02/21/2013 11:11 PM
Or, how about a counter-orbiting impactor, giving a relative velocity of 60km/s, far beyond chemical explosives. Could be accelerated slowly using very high-Isp ion thrusters, then kept in an heliocentric orbit ready to be commanded to intercept. (You'd need several of these so you could intercept within a month of command.)

I know that it's fun to speculate wildly, but there are some sources you could read out there about this. I've worked with the PI on the Deep Impact mission and he said that impacting that comet, which was 100 km wide, at 10 km/s, was very difficult to do. So trying to hit something even smaller at six times the relative velocity might be a little harder.

Nit to pick: The nucelus of the Temple 1 cometary target for Deep Impact was much smaller than 100 km, more like 6 km

Name             Dimensions    Density   Mass 
                     km              g/cm3      kg             
Halley's Comet 15 × 8 × 8   0.6       3×10^14
Tempel 1         7.6×4.9 (https://planetary.s3.amazonaws.com/assets/images/9-small-bodies/2012/20121218_asteroids_comets_sc_0-000-100_2012_color_brightened.png)       0.62   7.9×10^13
19P/Borrelly     8×4×4        0.3       2×10^13
81P/Wild         5.5×4.0×3.3 0.6  ] 2.3×10^13
(from a well referenced Wikipedia article (http://en.wikipedia.org/wiki/Comet_nucleus))

And Deep Impact did mange to hit close to the center of the sunlit area on the side of the fly-by, and was equiped to do so even if the nucelus had been irregular, rather than lumpy but nearly spherical.  Also, the impact was done with a relatively simple battery powered spacecraft using, IIRC, two lateral thrusters and a couple of roll control thrusters.  If the mission is destruction of a threatening comet or asteroid the top priority would no longer be having the majority of the spacecraft survive to send back data. 
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 02/21/2013 11:24 PM

Not entirely true, actually.

What's not entirely true? I said that life is still here. I think you'll find that is entirely true.  :)

The other point, that the impact of a Moon sized object could sterilize the Earth is probably true. But it obviously hasn't happened since life has arisen on this planet. The chance of that happening before the Sun becomes hot enough to destroy life on Earth is very small indeed. (There is apparently a few percent chance that the orbits of Mars or Mercury could become chaotic enough in four or five billions years time to cause planetary collisions.)

We don't have to worry about collisions of that magnitude. Impacts of objects the size of the Chelyabinsk meteor and up to kilometers in scale, we do, of course, have to worry about.
The "not entirely true" is referring to the Earth/moon impactor. If there was any life on Earth before that (probably not), then it would've been sterilized on Earth's surface by that impact. There are random things flying in space that could hit Earth and sterilize us again. Exceedingly unlikely (dismissively so), but possible. I was nitpicking. ;)
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Archibald on 02/22/2013 07:04 AM
For awhile, I was wondering how Russians were staying so calm driving their cars while this meteor lit up the sky. 
Chelyabinsk guys in Russia have a reputation for the most harsh. ;D
Type in a search engine "Суровые челябинские мужики настолько суровые, что" means "Harsh Chelyabinsk men are so harsh that" ;D

"Harsh Chelyabinsk men are so harsh that the fish jammed (concussied) by  meteorites" 
"Chelyabinsk residents are so severe that instead of snow in winter they are falling meteorites"
excuse my poor English


A few I understood:

Chelyabinsk guys are so tough, traffic cops bribe them.

Chelyabinsk programmers are so tough that they think
programming in assembler is a luxury -
they manually magnetize hard disk sectors.

Chelyabinsk vodka is so tough that it was banned as WMD
in 190 countries.

Chelyabinsk woodpeckers are so tough, they hollowed out
2 metro stations.

etc.


I see the point. It's just like the jokes with Chuck Norris or Zlatan Ibrahimovic...
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: douglas100 on 02/22/2013 07:46 AM
I was nitpicking. ;)

So was I.  :)
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Star One on 02/22/2013 08:07 AM
Not see these pictures before.

http://www.dailymail.co.uk/news/article-2282330/I-thought-nuclear-bomb-exploding-Photographers-breathtaking-pictures-Russian-meteorite-feared-live-through.html
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Ben the Space Brit on 02/22/2013 09:55 AM

Not entirely true, actually.

What's not entirely true? I said that life is still here. I think you'll find that is entirely true.  :)

It's true but misleading.

According to orthodox theory, life as we understand it appeared in the Cambrian explosion ~400 million years ago.  The heavy meteor bombardment stage of the solar system's history (when most of the Moon's craters were created, for example) occurred four billion years ago.

There have also been several occasions where a very large meteoric event came close to eradicating all life on Earth.  The infamous Yucatan Event is actually the smaller and less destructive of the two.  The other one occurred in the Deveronian period, IIRC, and took out about 90% of all vertebrate life.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: jgoldader on 02/22/2013 10:37 AM




It's true but misleading.

According to orthodox theory, life as we understand it appeared in the Cambrian explosion ~400 million years ago.  The heavy meteor bombardment stage of the solar system's history (when most of the Moon's craters were created, for example) occurred four billion years ago.

There have also been several occasions where a very large meteoric event came close to eradicating all life on Earth.  The infamous Yucatan Event is actually the smaller and less destructive of the two.  The other one occurred in the Deveronian period, IIRC, and took out about 90% of all vertebrate life.

The oldest microfossils go back to about 3.5 billion years ago, so prokaryotic life (cells without nuclei) was abundant by then.

The largest mass extinction known from the fossil record, which you mentioned, is the Permian-Triassic event, about 250 million years ago.  Marine life was almost wiped out, over 90% killed, and about 70% of land species as well.  As best as I can tell from a few quick searches, the P/T event's cause is still not quite pinned down, and it might have been a combination of too many stressors ranging from supervolcanism to an impact.

Though I recall reading many years ago that the greatest catastrophe for life on Earth might have been caused by... life on Earth.  The development of photosynthesis and the accompanying release of oxygen would have doomed the likely majority of single-celled organisms that relied on metabolizing inorganic chemicals (e.g., iron and sulphur compounds), for whom oxygen is a deadly poison.  Now that's a thought, brought me to a stop for a few minutes when I first read it.  The development of photosynthesis might have caused--literally--a genocide.

Jeff
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: JohnFornaro on 02/22/2013 01:05 PM
As best as I can tell from a few quick searches, the [Permian-Triassic ] event's cause is still not quite pinned down, and it might have been a combination of too many stressors ranging from supervolcanism to an impact.

I took a googol on that too, and my search suggested that the cause was liberal tax and spend policies, leading to a fungal spike.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: sanman on 02/22/2013 01:10 PM
ProjectB612: If the dinosaurs had a space program, they'd still be here.

Fornaro: If the dinosaurs had fiscal restraint, they'd still be here.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 02/22/2013 02:15 PM
Fiscal restraint, aka not making investments.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: douglas100 on 02/22/2013 02:16 PM

The oldest microfossils go back to about 3.5 billion years ago, so prokaryotic life (cells without nuclei) was abundant by then.

The largest mass extinction known from the fossil record, which you mentioned, is the Permian-Triassic event, about 250 million years ago.  Marine life was almost wiped out, over 90% killed, and about 70% of land species as well.  As best as I can tell from a few quick searches, the P/T event's cause is still not quite pinned down, and it might have been a combination of too many stressors ranging from supervolcanism to an impact.

Jeff

Thank you Jeff, you beat me to the reply. My point was simply that in the billions of years since the start of life on Earth there was been no impacts large enough to sterilize the planet. (There have been, as you mention, impacts which have done severe damage to the biosphere.) Therefore, I suggest such impacts are very rare indeed and should not concern us when it comes to planetary defense. There is not a lot we could do about deflecting a planet sized impactor, anyway.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: douglas100 on 02/22/2013 02:23 PM

It's true but misleading.

It only seems misleading because you've got the history of the time of the start of life on Earth wrong.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: smoliarm on 02/22/2013 03:16 PM
ProjectB612: If the dinosaurs had a space program, they'd still be here.

Fornaro: If the dinosaurs had fiscal restraint, they'd still be here.

If the dinosaurs had a space program... we won't be here.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: go4mars on 02/22/2013 03:32 PM
The largest mass extinction known from the fossil record, which you mentioned, is the Permian-Triassic event, about 250 million years ago.  Marine life was almost wiped out, over 90% killed, and about 70% of land species as well.  As best as I can tell from a few quick searches, the P/T event's cause is still not quite pinned down, and it might have been a combination of too many stressors ranging from supervolcanism to an impact.
There have been 5 very major mass extinction events.  "The big 5". 
I remember learning back in Uni days (from Charles Henderson, a P/T expert) that the Permian Triassic extinction was estimated to have completely erraticated 98% of species (not genera). 

Some guys figure the Permian/Triassic extinction was due to the the impact in Antarctica, which left a 500 km diameter crater.  Ever driven 500 kilometers?  That's a big impact.     Though somehow, "multi-causal" remains the consensus.

The 2% that lived weren't big complex creatures like us great apes.  Tough little fellers rather.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: aquanaut99 on 02/22/2013 03:45 PM

Some guys figure the Permian/Triassic extinction was due to the the impact in Antarctica, which left a 500 km diameter crater.  Ever driven 500 kilometers?  That's a big impact. 

http://www.bbc.co.uk/nature/extinction_events

Current research seems to point that the P/T super-extinction (aka "The day life nearly died") may in fact have been caused by a "Murder on the Orient Express" (all the suspects are guilty) type scenario. It seems there were actually 3 extinction pulses, spread out over a total of 100'000 years (very short time geologically!).

The suspects (who may all be guilty):
- Eruption of the Siberian Traps. One of the most massive volcanic events in the past billion years, released a lava flow that covered much of present Siberia, and probably dumped immense quantities of CO2 into the atmosphere. Mean global temperature probably rose by at least 10 degrees F due to this alone. These eruptions correlate very well with the first extinction pulse.
- Major anoxic event in the oceans (possibly as a consequence of climate change)
- Vast release of H2S from oceans (probably a consequence of no. 2, anoxic situation and lots of dead organic stuff), leading to a poisoning of life on land
- Massive release of CH4 from methane clathrates in the ocean
- Massive impact forming the Wilkes Land Crater in Antarctica
- Formation of the supercontinent Pangea with associated change in Sea-level and sea circulation
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: MP99 on 02/22/2013 03:54 PM
Not see these pictures before.

http://www.dailymail.co.uk/news/article-2282330/I-thought-nuclear-bomb-exploding-Photographers-breathtaking-pictures-Russian-meteorite-feared-live-through.html

When did it become "The 100,000-tonne space rock"?

Oh wait, it's the Daily Mail.  ::)

cheers, Martin
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: go4mars on 02/22/2013 04:02 PM
This:
Massive impact forming the Wilkes Land Crater in Antarctica
Could have been the cause of these:

- Eruption of the Siberian Traps.
- Major anoxic event in the oceans (possibly as a consequence of climate change)
- Vast release of H2S from oceans (probably a consequence of no. 2, anoxic situation and lots of dead organic stuff), leading to a poisoning of life on land
- Massive release of CH4 from methane clathrates in the ocean

It seems there were actually 3 extinction pulses, spread out over a total of 100'000 years...
IIRC that is based on just one site in Greenland, and is in dispute.  Though I won't discount the possibility.  For example, the big smack might have caused Siberian eruptions to commence, which happenned on their own good timing.  Not unlike a possible relationship between Deccan traps eruptions taking something like 30000 years after the Cretaceous impact(s). 
I don't know if anyone has studied the mechanism with any sense of conclusivity.

Or for example, the hot water didn't circulate to a deep area rich in clathrates until thousands of years after the event.    etc.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: smoliarm on 02/22/2013 04:03 PM
Here I attach the map with details on Chelyabinsk meteorite damage and meteorite fragments recovery, compiled from reliable sources.

FIRST thing to note - very uneven character of the shock wave, almost lateral. Moreover, it is NOT symmetrical relative to the flightpath, nor does it follow the distance rule like nuke explosion wave:
The trajectory was approximately East to West, slightly to South from Korkino. However, town of Kopeisk suffered ~ twice more damage than Korkino, although it is some 30 km to the North.

Total amount of broken window glass > 150,000 m2
Chelyabinsk – 59%
Kopeisk – 24%
Korkino – 12%
Other sites – 5%

SECOND: meteorite fragments are already found in areas to the EAST of main explosion (#16 on map). This indicates that the fragmentation of original mass started very early, at least before the beginning of glowing part of the flight.

THIRD: The flight trajectory seems to be from ENE to WSW:
http://www.meteorites.ru/images/yuzhnouralsky2013/eumetsat_pulkovo_02.jpg
however, the recovered (or reported) falls seem to follow ESE - WNW path.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Prober on 02/22/2013 04:10 PM
Fiscal restraint, aka not making investments.

political statement without understanding.
 
Fiscal restraint = Control of spending (hard to put one out that can't be taken as political)
 
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Prober on 02/22/2013 04:13 PM
You couldn't want to blast and create a debris field.

The advantage of cracking an incoming meteor is the smaller the bits, the higher up the bits breakup. Chelyabinsk was ~500 kt at ~30km, if it had been 500 kt at a couple of km the outcome would have been much more tragic. You still will have the same amount of energy released, it just be at a higher altitude. An end game that attempts to crack them just before entry could save lives from the 10m plus objects.

The perfect time to crack would be once entrance into the upper atmosphere.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: spacermase on 02/22/2013 04:15 PM




The suspects (who may all be guilty):
- Eruption of the Siberian Traps. One of the most massive volcanic events in the past billion years, released a lava flow that covered much of present Siberia, and probably dumped immense quantities of CO2 into the atmosphere. Mean global temperature probably rose by at least 10 degrees F due to this alone. These eruptions correlate very well with the first extinction pulse.

- Massive release of CH4 from methane clathrates in the ocean


From what Peter Ward has said, the Siberian Traps were unfortunately also located near massive coal fields (which, of course, also released massive amounts of CO2), and at least part of the volcanic field was near a shallow sea, so the lava flows may have touched off clathrate deposits directly.

It really was Murphy's law as applied to mass extinctions.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: go4mars on 02/22/2013 04:25 PM
Fiscal restraint, aka not making investments.

political statement without understanding.
 
Fiscal restraint = Control of spending (hard to put one out that can't be taken as political)
 
I think it was intended as a humourous comment in the context of dinosaurs not building early warning systems for rogue asteroids.  Non-partisan and clever.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: smoliarm on 02/22/2013 04:25 PM
If anybody cares how it looks like, here it is, the dinosaur extinctor.

natural fragment
http://www.meteorites.ru/images/yuzhnouralsky2013/img_8525.jpg

cut and polished
http://www.meteorites.ru/images/yuzhnouralsky2013/img_0003.jpg
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 02/22/2013 05:19 PM
@Prober: (removed my message, better fit for private message) Suffice it to say I wasn't speaking without understanding.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: JohnFornaro on 02/22/2013 05:48 PM
ProjectB612: If the dinosaurs had a space program, they'd still be here.

Fornaro: If the dinosaurs trilobites had fiscal restraint, they'd still be here.

Fixed that for ya.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Antares on 02/23/2013 02:53 AM
Lazy question as I ponder how to explain what caused the damage to non-techies:

What other natural phenomena (not man-triggered events) create airborne sonic shocks?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 02/23/2013 03:01 AM
Lazy question as I ponder how to explain what caused the damage to non-techies:

What other natural phenomena (not man-triggered events) create airborne sonic shocks?
Volcanic activity.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Mongo62 on 02/23/2013 03:31 AM
What other natural phenomena (not man-triggered events) create airborne sonic shocks?
Lightning.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: kevin-rf on 02/23/2013 11:53 AM
Beans
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: R7 on 02/23/2013 12:33 PM
Beans

I believe those produce choking flows, not choked flows  ;D
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: JohnFornaro on 02/23/2013 01:07 PM
Beans

I believe those produce choking flows, not choked flows  ;D

There went the coffee.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Zoomer30 on 02/23/2013 05:52 PM
When you consider that the Earth is about 70% water and 30% land, I feel that we dodged a major bullet that this object did not hold together and impact a large ocean (Pacific or Atlantic basin)

Have any calculations been made to try to predict what size of tsunami this kind of object would have produced? When you consider that a chunk of Hawaii falling into the ocean is suspected of triggering a "mega-tsunami" that deposited coral seafloor high on a cliff in Australia, I think this could have been much worse.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: js117 on 02/24/2013 03:07 AM
When you consider that the Earth is about 70% water and 30% land, I feel that we dodged a major bullet that this object did not hold together and impact a large ocean (Pacific or Atlantic basin)

Have any calculations been made to try to predict what size of tsunami this kind of object would have produced? When you consider that a chunk of Hawaii falling into the ocean is suspected of triggering a "mega-tsunami" that deposited coral seafloor high on a cliff in Australia, I think this could have been much worse.

This Meteor was only 50 feet in diameter.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Antares on 02/24/2013 04:57 AM
Seriously, please understand the difference between shocks and sound waves or Mach waves.

Lightning is a hard sell, but it's accurate.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: rdale on 02/24/2013 06:48 AM
And it wasn't that big when it landed. It would have made a little ripple or two in the middle of the ocean.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: smoliarm on 02/24/2013 07:53 AM
From my German friend I heard a song - a kid-song - with this line:
"Wenn meine Tante Räder hätte, so wäre sie ein Omnibus!"
Loosely translated:
"If only my aunt had four wheels, she'd be a bus!"


>>When you consider that a chunk of Hawaii falling into the ocean...
the HIGHEST so far estimate for this meteorite is 17 meters in diameter, and it is very questionable.
However, even this is pretty far from "a chunk of Hawaii"

>>Have any calculations been made to try to predict what size of tsunami this kind of object would have produced?
No need for calculations, you can refer to photos:
http://bm.img.com.ua/berlin/storage/orig/9/5b/2be9e9074bfe57637da55931f502a5b9.jpg
http://slon.ru/images2/blog_photo_18/2013_02_15/meteorit1-1.jpg
All these objects (chondrites, comet nuclei, etc) are very fragile, they break up in atmosphere very early in tiny pieces most of which burn completely. Therefore, the blast wave is more dangerous (by far) than any impact effects.
On these photos you see the BIGGEST impact damage, the shock wave damage was MUCH worse, about 170,000 m2 of broken window glass.

Earthquake Tsunamis are common and dangerous, and by multiplying the magnitude of the last one by x10 you create a Global Disaster. From the other hand, there is no case in the entire recorded history of meteorite tsunami.
Reasonable conclusion - the focus should be on earthquakes, twisters and hurricanes, the meteorites present comparatively minor threat.


Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: R7 on 02/24/2013 10:32 AM
Have any calculations been made to try to predict what size of tsunami this kind of object would have produced? When you consider that a chunk of Hawaii falling into the ocean is suspected of triggering a "mega-tsunami" that deposited coral seafloor high on a cliff in Australia, I think this could have been much worse.

The "chunk of Hawaii" weighs so many orders of magnitude more than the russian rock that the differences in energies released is several orders of magnitude too.

The russian meteorite yield was about 300-500kt IIRC. There have been underwater nuclear test 23kt Shot Baker and 15Mt Castle Bravo at Bikini atoll, and it's still there (albeit with big holes), no tsunamis ensued.

Shot Baker:

http://www.youtube.com/watch?v=MQ4DqdIIBzM (http://www.youtube.com/watch?v=MQ4DqdIIBzM)

and Castle Bravo (largest H-bomb detonated by US):

http://www.youtube.com/watch?v=R5_9Gi7w19Y (http://www.youtube.com/watch?v=R5_9Gi7w19Y)
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Danderman on 02/24/2013 03:29 PM
I would guess that some rogue waves are caused by distant meteor falls.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: hop on 02/24/2013 06:21 PM
I would guess that some rogue waves are caused by distant meteor falls.
I very much doubt they are a significant source. We know that most things up to the size of the Chelyabinsk body (and even quite a bit larger) detonate at high altitude, and we know that impacts this size are extremely rare. With things like CTBTO infrasound network, events on this scale will be detected no matter where they occur.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Blackstar on 02/24/2013 11:39 PM
When we did our NEO study we had some discussions of the issue of tsunamis caused by meteors. Jay Melosh is one of the foremost experts on impacts (he's the one who created that website where you can plug in an asteroid and see the effects). From what I remember, he said that it was doubtful that you'd get tsunami effects from a relatively large one (for various definitions of "large") hitting in the middle of the ocean. Tsunamis are highly dependent upon the shape of the ocean floor, so a decent sized meteor hitting in shallow water will definitely produce a tsunami, but in the middle of the deep ocean it is doubtful.

But like I said, it depends upon your definition of large.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: smoliarm on 02/25/2013 01:50 PM
I would also be very interested in eyewitness reports of electrophonic sound PRIOR to the acoustic shock -- that is, during the brightest flaring of the fireball. This is a at-long-last well-established effect of plasma-generated radio noise coupling into near-observer physical objects and creating a hissing or whooshing sound. It occurs simo with the visual flares, seems to come from 'all around' [not from above], has been reported for centuries by some bright fireball witnesses and pooh-poohed by scientists until work by Colin Keay and others established its validity. 

Jim, there were indeed plenty of such reports. Today's article
http://chelyabinsk.ru/text/newsline/625214.html
is titled
**Болид, взорвавшийся над Челябинском, оказался «звучащим»**
**Chelyabinsk Fireball turned out to be "sounding"**

Article says 27 eyewitnesses independently noted that they heard weak but clear hissing sounds DURING the flight. Many of them compared the sound with "Bengal sparkler" (Popular in Russia type of hand-held light firework) and noted that could not determine neither the source of hissing nor direction it came from.

This information was gathered via internet-form for eyewitness reports here:
http://www.chel-meteorit.youini.ru/
I'd like to note that there is no direct question in the form about this effect, the respondents were NOT prompted to describe it, they all did it in "Additional Comments" field.

Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: sdsds on 02/25/2013 08:28 PM
Asteroid defence
The real star war
Something useful for America’s underemployed space agency to do

http://www.economist.com/news/leaders/21572203-something-useful-americas-underemployed-space-agency-do-real-star-war
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: JimO on 02/25/2013 10:14 PM
Jim, there were indeed plenty of such reports.

Oh, WOW!  Thanks!

Let me get over to that site and try to read it -- I have a hard enough time with American blog-speak, but I know street Russian pretty well. Hmmm...

Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: JimO on 02/25/2013 10:22 PM
Today's article
http://chelyabinsk.ru/text/newsline/625214.html
is titled **Chelyabinsk Fireball turned out to be "sounding"**

I tried to 'register' to allow posting a comment but that page was forbidden. Do they have some za rubezhom filter?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: catdlr on 02/26/2013 01:14 AM
ScienceCasts: What Exploded Over Russia?

Published on Feb 25, 2013
Visit http://science.nasa.gov/ for breaking science news.

Two weeks after an asteroid exploded over Russia's Ural mountains, scientists are making progress understanding the origin and make-up of the unexpected space rock. This week's ScienceCast presents their latest results.

http://www.youtube.com/watch?v=-qZ6oiaSm00
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: go4mars on 02/26/2013 02:25 AM
there is no case in the entire recorded history of meteorite tsunami.
Does Burckle crater not count?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: smoliarm on 02/26/2013 11:39 AM
Today's article
http://chelyabinsk.ru/text/newsline/625214.html
is titled **Chelyabinsk Fireball turned out to be "sounding"**

I tried to 'register' to allow posting a comment but that page was forbidden. Do they have some za rubezhom filter?


Most likely, they just have some advanced spam filter.
This site - chelyabinsk.ru - is just a local news agency, they suffer a lot from spam :(

In case you need additional information, I have better idea - I could try to find a contact with Gorokhovski for you. He is the leader of Ural University team working on Chelyabinsk meteorite. I do not know him personally, but hopefully I could get his email from friends.

Some details on electrophonic effects in Chelyabinsk which did not make it to the news:
# It looks like the level of electrophonic sound was indeed low, most reports of *hissing* fireball came from quiet country places.
# One eyewitness was able to point to the source of sound. She believes that it was the TELEPHONE cable of external line (from the pole to the house).
# Another report of fireball with hissing sound was from a village some 120 km to the East from Chelyabinsk. Here, the person described it as *low level cracking HUM very similar to what you hear near high voltage power line*.

==============================
It happened so I just came across the case of well-documented eyewitness account of electrophonic sound with another meteor event, Vitim Bolide.
Here is the original article:
http://www.scientific.ru/journal/vitim.html
The article itself discusses general things, eyewitness report of electrophonic sound is in this paragraph:
“Очевидец Ярыгин Евгений Сергеевич”

Quote
"… далекий звук возник еще до появления свечения - похожий на гул от самолета. Звук шел с той же стороны, что и свечение, а удар пришел с противоположной стороны, куда ушло свечение".

"… distant sound came even before the beginning of glowing, it was like distant airplane hum. Sound came from the same side as glowing. The blast came from the opposite side, where the glowing went. "

Vitim Bolide (or Vitim event) is briefly described in Wiki:
http://en.wikipedia.org/wiki/Vitim_event
I have to note, that wiki paragraph about “Kosmopoisk expedition” should be disregarded, their report turned out to be erroneous.


Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: smoliarm on 02/26/2013 11:59 AM
there is no case in the entire recorded history of meteorite tsunami.
Does Burckle crater not count?

Of course, it does not  :)
I am talking about historical records and about events

This does not mean that there was no *splash*, given the size of crater there was a big splash  ;)

My point is - we know almost nothing about it, no records and no details are available. That's the difference: observed and recorded (documented) events we can study, on traces like Burckle crater we can speculate.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Ben the Space Brit on 02/26/2013 12:44 PM
An interesting item on the BBC News website (http://www.bbc.co.uk/news/science-environment-21579422).  One group of scientists claim to have come up with a reasonable probable orbit for the Chelyabinsk Meteor.

There is a very large degree of uncertainty but, if their figures are correct, then the meteor originated in the Main Belt and had an orbit with a perihelion close to the Sun than the Earth.

It might be interesting to speculate the exact origins.  One obvious possibility is that it was perturbed out of its original orbit by the gravity of Jupiter lining up with other planets.  Alternatively, it could be the result of a comet/asteroid collision, in which case, there might be other objects (smaller, certainly and one or two perhaps larger) in similar orbits.  That might explain the San Francisco and Cuba meteorites - they could be part of the same cluster of objects.  It might be worthwhile to properly sweep the estimated orbits with high-power telescopes to see if there are any more unpleasant surprises waiting along that track.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: kevin-rf on 02/26/2013 01:08 PM
Interesting, I wonder how it meshes with the earlier preliminary orbit

http://forum.nasaspaceflight.com/index.php?topic=31118.msg1014412#msg1014412
Quote
Haven't seen this posted yet, preliminary orbit: http://blogs.nasa.gov/cm/blog/Watch%20the%20Skies/posts/post_1361037562855.html

The Blog with more:
http://blogs.nasa.gov/cm/newui/blog/viewpostlist.jsp?blogname=Watch%20the%20Skies
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: R7 on 02/26/2013 01:32 PM
there is no case in the entire recorded history of meteorite tsunami.
Does Burckle crater not count?
Of course, it does not  :)
I am talking about historical records and about events

Exodus 14:19-29 "pillar of cloud", water recedes, rushes back ... hey who knows?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: ChileVerde on 02/26/2013 01:33 PM

An estimate of the orbit:

http://www.technologyreview.com/view/511691/astronomers-calculate-orbit-of-chelyabinsk-meteorite/

http://arxiv.org/pdf/1302.5377v1.pdf


Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: ChileVerde on 03/02/2013 11:43 PM

Quote
http://science.slashdot.org/story/09/06/22/1625254/us-military-blocks-data-on-incoming-meteors
http://blogs.nature.com/news/2009/07/post_30.html
http://www.nature.com/news/2009/090612/full/459897a.html
http://www.space.com/6927-military-seeks-common-ground-scientists-fireball-data-flap.html

Current news about this:

Quote
http://www.space.com/19846-russian-meteor-fallout-military-satellites.html

Russian Meteor Fallout: Military Satellite Data Should Be Shared
by Leonard David, SPACE.com’s Space Insider Columnist
Date: 18 February 2013 Time: 09:03 AM ET

 Piecing together the true nature of the meteor that detonated over Russia would benefit by observations likely gleaned by U.S. military spacecraft.

But for several years, that data has been stamped classified and not made available to the scientific community that study near-Earth objects (NEOs) and any potential hazard to Earth from these celestial interlopers.

In the wake of the Russian meteor explosion, there is a renewed call to make data gathered by both space systems and ground networks speedily available to scientists.

<considerable snip>

Apparently it was a done deal even before the Russian event:

Quote
http://www.space.com/19966-russian-meteor-asteroid-deflection-options.html

Russian Meteor Fallout: What to Do Next Time?
by Leonard David
Date: 26 February 2013 Time: 03:12 PM ET

This month's meteor detonation above the Russian city of Chelyabinsk and Earth's close shave with asteroid 2012 DA14 have kick-started conversations on lessons learned and what steps can be taken to prevent space rock impacts in the future.

One positive action item was actually in place prior to the dual asteroid events of Feb. 15: a new Memorandum of Agreement between the Air, Space, and Cyberspace Operations Directorate of the Air Force Space Command and NASA’s Science Mission Directorate.

That document, which was signed on Jan. 18 of this year, spells out specifics for the public release of meteor data from sources such as high-flying, hush-hush U.S. government space sensors.

The recent Russian meteor event occurred after completion of the newly signed agreement and data on the recent Chelyabinsk event had been released for scientific analysis, SPACE.com has been informed by NASA and the U.S. Air Force.

As a result of that agreement, NASA’s Near Earth Object (NEO) Observation Program is receiving information on bolide/fireball events "based on analysis of data collected by U.S. government sensors."

http://neo.jpl.nasa.gov/fireballs/
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: go4mars on 03/06/2013 04:03 PM
There is some speculation... that the Younger Dryas was punctuated by one or more North American impacts of regional affect.  Just south of one of the Great Lakes, there is what looks like a melt-path, clearly viewable on google earth satallite imagery, where it sorta looks like a bunch of the native rock there was flash-melted then flowed.  Also, there are a bunch of small lakes/depressions across the mid-east of North America that are perhaps impact related.  IIRC, there was even some shocked quartz found related to Younger Dryas impacts, and some regional char layers here and there.  Some suggest that an alternate theory for the giant floods that have been documented during the last glaciation, is flash-melting of enormous volumes of continental ice sheet, as opposed to ice bridges/plugs letting go.  There is debate about the conclusions and scale, but I think that in a couple decades the consensus will tip toward the impact hypothesis.   
To add to this, Bloody Creek Crater, Charity Shoal crater, Carossol crater are known examples.  Iturralde crater is in Bolivia, but might line up time-wise.  Melt glass in the middle east too, etc.     The great Lake Agassiz flood (flash melt of huge ice volumes may be responsible).  Hobbits went extinct (homo floresiensis). And some of the melted rock, not the stuff I was looking for, was just south of Lake Superior.


http://wattsupwiththat.com/2012/06/13/new-evidence-of-younger-dryas-extraterrestrial-impact/

http://www.pnas.org/content/109/13/E738.full
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: indaco1 on 03/13/2013 09:16 PM
I dare to make a question for the experts of astrodynamics.

Chelyabinsk meteor and 2012 DA14 had widely different trajectories.

Ok, but are they really unrelated?  It seems really coincidental.

I know nothing about celestial mechanics but I know that many strange phenomenons exists like orbital resonance, lagrange points, Trojans, quasi-satellites, horseshoe orbits,  interplanetary transport network, co-orbital moons etc.

In other words, could some undisclosed effect increase the probability that two asteroids having widely different trajectories approach Earth at the same time?

I know it's a complex matter...
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: srtreadgold on 03/21/2013 01:21 PM
In regards to asking whether they could have come from the same parent body at some point way back in time: "Definitely not from 2012 DA14 - the timing and direction of the Russian meteor are wrong to be from that asteroid or to have been traveling in a similar orbit. So no to the parent body as well." - from the Meteoroid Environment Office at MSFC
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: aero on 03/21/2013 01:58 PM
I don't even know how to precisely phrase this question but it has to do with the probabilities of significantly large meteoroids hitting earth.

Because two meteoroids reached earth vicinity, one strike and one near-miss on the same day, does that change the calculation of the probability of an impact on earth in the future?

If the meteoroids did have the same orgin, then the answer would clearly be, "No." But the experts see these two bodies as being totally independent, with the only thing in common being their nearness to earth on the same day. What is the probability of that happening?

A related question, "How large does a meteoroid need to be to cause a visible fireball on impacting earth's atmosphere, as apposed to the streaks of light commonly seen in meteor showers?"

Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: kevin-rf on 03/21/2013 02:20 PM
To be visible at night they often say the size of a pea, to be considered a bolide (fireball greater than -3 magnitude) they often say baseball sized. Wish I could find a good internet source on meteor sizes verses intensity.

It is variable since observing distance from the meteor and meteor entry speeds  (15-70 km/s) vary greatly.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: pippin on 03/21/2013 02:28 PM
Because two meteoroids reached earth vicinity, one strike and one near-miss on the same day, does that change the calculation of the probability of an impact on earth in the future?
Not at all. You can't calculate any probabilities based on a single event, coincidence event are no exception to that.
Theoretically, these two could even have been the only ones coming close to earth and the probability of that happening at the same day could be a one-in-100-billion-years equivalent, then that one event in 100 billion years could still have been that very day.

So no, no change. To calculate probabilities you need to count asteroids, lots of them and calculate their orbits.
Or you can count historic impacts, although that's hard on earth.
Or you can count impacts on the moon, historic and current.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 03/21/2013 04:22 PM
It does somewhat affect one's calculation, but not in a straight-forward way...

There's always a chance your original calculation based just on analysis of asteroids (and not on impacts actually that occur) is making a large systemic error, leading either to over- or under-conservative estimation of risk. Having a few asteroids hit or make close call does effect one's interpretation of the calculation because it provides extra data (as does not having any impacts), though it is statistical in nature (but what isn't).

EDIT:To give a synthetic example: Suppose you calculated that the chance of a near-miss or collision of an object in the size range we talked about was 10^-10 per year... Clearly, if you have two objects hit or nearly hit within a short timeframe (a day or so) and appear to be completely independent events, then it is much more likely your calculation of the probability was wrong than that you just experienced an event not likely to happen within a trillion times the age of the Universe.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Warren Platts on 03/21/2013 06:21 PM
Do we know for sure that the one isn't a fragment of the other?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: kevin-rf on 03/21/2013 07:10 PM
Considering how different the orbits are, if it is, it happened a very very long time ago and had it's orbit altered greatly. More likely they both came from different parent bodies.

Do we know the composition of DA14? If they are not the same, that would be a clincher.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Targeteer on 03/21/2013 10:59 PM
For those in the US, PBS' NOVA program on 27 Mar will cover the search for fragments.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: smoliarm on 03/22/2013 12:00 AM
Considering how different the orbits are, if it is, it happened a very very long time ago and had it's orbit altered greatly. More likely they both came from different parent bodies.

Do we know the composition of DA14? If they are not the same, that would be a clincher.

>>Do we know the composition of DA14?
No.
We do know it is a type L asteroid, of S-class. This classification is based on spectral data and in general reflects composition, but we do not know any details.

Chebarkul meteorite belongs to ordinary chondrites, namely to L-class (but this has nothing to do with type L asteroids, it's just a coincidence of classification letters). Chondrite classification is based on their chemical composition, typical values and variations for most classes are well established. But it is impossible to match meteorite compositional classes with spectral types of asteroids WITHOUT a reference point, without direct sampling of asteroids.

This is why sample-return mission to asteroid has a GREAT scientific value. For cosmochemistry and planetology, it would be comparable with effect of lunar sample return.

============================
>>Do we know for sure that the one isn't a fragment of the other?
It depends how you define "for sure" :)
They have substantially different orbital planes. This makes their relation ("a fragment of the other") HIGHLY unlikely.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: pippin on 03/22/2013 12:11 AM
Clearly, if you have two objects hit or nearly hit within a short timeframe (a day or so) and appear to be completely independent events, then it is much more likely your calculation of the probability was wrong than that you just experienced an event not likely to happen within a trillion times the age of the Universe.

No, sorry, this is wrong. This would be a single event and would have zero effect on your calculation.
To be able to even take them into account mathematically you'd need at least 30 of them (as of the central limit theorem)

You can calculate the probability for such an event given your current knowledge about the number of asteroids and so on, but with just a single event, no matter how improbably it is, you don't know whether that's within the range of your assumptions or not. As I said before: even if the probability says this is only going to happen once over the entire life of the universe you don't know whether this was that one event. And no probability, how low it may be, can ever rule out a single event.

That's a common misconception about statistics: that if you know a probability and something happens you can predict what happens next. It's a common error e.g. with numbers for a lottery. People often believe, that if a certain number is drawn now, it would be very, very unlikely that it's being drawn again the next time. But in fact it's just as likely as for any other number, even one that hasn't been drawn for ages.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: sdsds on 03/22/2013 03:35 AM
That's a common misconception about statistics

I doubt Robotbeat is suffering from the misconception you describe!

We don't know much about the frequency at which Earth encounters objects the size of the one that entered over Chelyabinsk. As I read it, Robotbeat was simply suggesting some assumptions about the rate of those encounters may have underestimated the actual rate.

Robotbeat was careful not to specify why that rate may have been underestimated, he merely observed the possibility of some sort of systemic error.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Warren Platts on 03/22/2013 01:15 PM
I don't think we can rule out that the meteor and asteroid are not unrelated just because it's too much of a coincidence that they both happened on about the same day. As Jorge pointed out earlier, an asteroid coming up from the south can still impact the northern hemisphere. I checked out the paper that calculated the orbit of Chelyabinsk, and we certainly can't consider it conclusive since the authors of the paper do not:

Quote
Assuming that the hole in the ice sheet of Lake Cherbakul was produced by a fragment of the meteoroid is also a very important hypothesis of this work. More importantly, our conclusions relies strongly onto assume that the direction of the trajectory of the fragment responsible for the breaking of the ice sheet in the Lake, is essentially the same as the direction of the parent body. It could be not the case. After the explosion and fragmentation of the meteoroid fragments could acquire different velocities and fall affecting areas far from the region wher we expect to find.

We don't even know if the hole in the ice of Lake Cherbakul was even caused by the meteor! After all, I thought divers were unable to find any meteorite fragments there...
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mlindner on 03/22/2013 05:30 PM
I don't think we can rule out that the meteor and asteroid are not unrelated just because it's too much of a coincidence that they both happened on about the same day.

NO absolutely not. We back tracked the orbits of both rocks and they are on ENTIRELY different orbits with very different energies. It is straight out impossible that both rocks had any interaction probably in the last million years at the very least. Timing has nothing to do with it. If you have enough independent events occasionally the time spaces of both of them intersect.

I'm not aware of the paper you quote. Every estimate I've seen that back tracked the orbit made no reference to that suspected crater. People used seismic data and the visual video evidence. Not to mention the satellite footage.

From the satellite image you can get quite precise direction and from the angle in the videos you can get entry angle. There also several images showing the decent path from a high altitude aircraft which allows a better estimation of angle.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Warren Platts on 03/22/2013 06:13 PM
Sorry, here's the link:

http://arxiv.org/pdf/1302.5377v1.pdf

These guys didn't use satellite data. Perhaps you have a link to the study you're referring to?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mlindner on 03/22/2013 08:44 PM
Sorry, here's the link:

http://arxiv.org/pdf/1302.5377v1.pdf

These guys didn't use satellite data. Perhaps you have a link to the study you're referring to?

Was that really released 6 days after the impact? I'm surprised they got enough data together and ran the analyses and wrote the paper in that short amount of time.

Edit: Couldn't find the article I saw, but here is an updated paper from those same authors.

http://arxiv.org/pdf/1303.1796v1.pdf
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: mlindner on 03/22/2013 09:01 PM
I think they have also more or less confirmed that the hole in the lake is indeed from A meteorite. Unless of course, there was yet _another_ meteorite that also struck that lake in the same time period. They found meteoric fragments all around the hole.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: smoliarm on 03/23/2013 07:55 PM
I think they have also more or less confirmed that the hole in the lake is indeed from A meteorite. Unless of course, there was yet _another_ meteorite that also struck that lake in the same time period. They found meteoric fragments all around the hole.

It is 100% confirmed that the hole in Chebarkul ice was made by the fragment of the same meteorite - there are 50+ small chips collected from the surrounding ice. They are identical in composition with the rest of material of this meteorite (collected in other places).

From Warren Platts:
Quote
After all, I thought divers were unable to find any meteorite fragments there...

They did not find meteorite merely because they DID NOT look for it - believe it or not :)
This was a military emergency response team, they were checking for something radioactive or otherwise harmful - by the book. As for meteorite, they did not have a first clue how to identify it, that's why they did not find it.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: smoliarm on 03/23/2013 08:09 PM
That's a common misconception about statistics

I doubt Robotbeat is suffering from the misconception you describe!


I can confirm that pippin is right on both accounts:
1. That quote from Robotbeat does have statement which is incorrect.
2. And yes, this is a common misconception.

There is nothing strange about it, this bit of probability theory is contra-intuitive, at least quarter of my students made same or similar mistake.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 03/23/2013 08:44 PM
If you experience an incredibly, incredibly unlikely event (according to some model), you might be just experiencing  a statistical aberration, but more likely your model is incorrect (or, of course, selection bias or something...).

Note that I have no reason to think that our estimates of impact probability are wrong by several orders of magnitude (or even off at all), but if your models WERE off by several orders of magnitude then yeah, it doesn't take a large sample size for you to consider maybe your model is incorrect.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 03/23/2013 08:53 PM
Clearly, if you have two objects hit or nearly hit within a short timeframe (a day or so) and appear to be completely independent events, then it is much more likely your calculation of the probability was wrong than that you just experienced an event not likely to happen within a trillion times the age of the Universe.

No, sorry, this is wrong. This would be a single event and would have zero effect on your calculation....
Not true. It depends on the details. For instance, if I measure the resistance of a component once, even though I have a sample size of one, my confidence is pretty high (given I have a calibrated meter, etc) that the resistance is such-and-such.

Or for instance (to give a cliche car analogy), suppose I go around a corner (driving carefully, not too fast) in a car with the assumption that the road is non-slippery but I lose traction, my wheels slip, and I almost crash. What kind of person would think that this single event should have zero effect on my calculation on whether the road is slippery or not? And no, the answer is not "a scientist."

A small sample size of one or two CAN, under certain circumstances, provide useful information or cast doubt on one's model.

In these circumstances of a close pass and a collision, they don't effect current models because the models already say that close-passes are relatively common and large hits can happen between once a decade and once a century.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: ChileVerde on 03/23/2013 10:53 PM

<snip>


Are we getting into a Bayesian vs frequentist argument here?

http://www.behind-the-enemy-lines.com/2008/01/are-you-bayesian-or-frequentist-or.html
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: smoliarm on 03/24/2013 12:13 AM
to Robotbeat:
This is close to off-topic, so I'll try to be concise.

Your statement
Quote
Clearly, if you have two objects hit or nearly hit within a short timeframe (a day or so) and appear to be completely independent events, then it is much more likely your calculation of the probability was wrong than that you just experienced an event not likely to happen within a trillion times the age of the Universe.
is incorrect, it violates fundamental principle of probability theory: single event does not provide any basis to estimate its probability.

Unfortunately, I can refer you to textbooks in Russian, I never got to teach such basic course in English. (I used to teach advanced statistics in application to analytical chemistry, but it's grad level).
Your follow-up posts are basically attempts to built a kind of statistical 'Perpetuum mobile'. It won't work, take my word :)

MOREOVER, there are two more reasons this dispute has no sense.
FIRST: modern models for estimation of catastrophic impact probability are fairly unreliable, nobody argues against that. May be crap is better word.
SECOND: Even if you get the right probability number - how are you going to convince public,media, congress et al., that they need to spend money on appropriate early warning system ?

Finally, to the topic -- I strongly hope that this double event - DA14 and Chebarkul - WILL help B612 with their Sentinel project.

Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: deltaV on 03/24/2013 03:06 AM
Those two NEO events are two additional data points that may factor into our estimates of NEO probabilities, but:
* Our response to them should be identical to how we'd react if they'd happened months apart.
* Our estimates probably won't change much since these events aren't unexpected.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Robotbeat on 03/24/2013 03:56 AM
smoliarm:
Except if you are dealing with a very small number of samples (or essentially none, as in the case of large asteroid impacts that have been observed with cameras), then yeah, one or two additional samples could have a significant effect. In this case it doesn't because we've been tracking thousands of asteroids.

But you are apparently misreading my point. In reality our models are good enough that these two events make essentially no impact on our probability estimates. I never said that they did. I only disagreed with the notion that "under no circumstances could just these two events have any impact (heh) on our probability estimates." Because, yeah, there are some circumstances where just two events could possibly affect our estimates. Just not our current circumstances.

And yeah, I agree the situation is the same as if they had happened months apart.

Ask yourself whether finding independently evolved life on another nearby planet would affect our estimates of the Drake equation, for instance... (Of course they would because our current estimates of the Drake equation are wildly spread over several orders of magnitude... Adding a second data point would tremendously improve our estimates.)
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Targeteer on 03/28/2013 12:59 PM
For those in the US, PBS' NOVA program on 27 Mar will cover the search for fragments.

Just watched the program on the DVR.  Interesting and detailed.  The object was mostly rock (90%) and orbitology showed that the earth actually ran down the object from behind.  The largest fragment shown was slightly smaller that a baseball.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Moe Grills on 03/28/2013 08:34 PM
Clearly, if you have two objects hit or nearly hit within a short timeframe (a day or so) and appear to be completely independent events, then it is much more likely your calculation of the probability was wrong than that you just experienced an event not likely to happen within a trillion times the age of the Universe.

No, sorry, this is wrong. This would be a single event and would have
In these circumstances of a close pass and a collision, they don't effect current models because the models already say that close-passes are relatively common and large hits can happen between once a decade and once a century.

I have to shake my head in disgust at the abstract impersonal debate
developing.
  Do all of you realize that that meteoroid/asteroid HAD a major orbital axis
that once stretched well over 200 million klicks before it slammed into our atmosphere? And it released most of its energy 30 klicks above a major Russian city?
Compare 30 klicks to over 200 million klicks.
In other words? If it had exploded with over 400 kilotons of energy released, 10 kilometers closer to earth, the shockwave over-pressure would have KILLED THOUSANDS of human beings like you and me.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: aero on 03/28/2013 09:28 PM
From Wikipedia
Quote
Chelyabinsk Meteor 17 to 20 metres across

If the meteor had struck more centrally, more of a direct hit than it did, then it may well have penetrated lower into the atmosphere before exploding.

Our NEO detection methods don't begin to catalog these small objects and they only strike every few generations so I guess everyone we know now is probably safe from them. But some areas have a higher population density than Chelyabinsk and population density is generally increasing, so how soon will it be before the risk from these small asteroids becomes worrisome?

Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: rickl on 03/28/2013 10:56 PM
For those in the US, PBS' NOVA program on 27 Mar will cover the search for fragments.

Just watched the program on the DVR.  Interesting and detailed.  The object was mostly rock (90%) and orbitology showed that the earth actually ran down the object from behind.  The largest fragment shown was slightly smaller that a baseball.

I just watched it online.  Very good documentary.  Here's the link:

http://video.pbs.org/video/2358778286
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: AndrewSTS on 03/29/2013 08:29 PM
That was very interesting, thanks!
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: kevin-rf on 03/31/2013 10:56 PM
Thanks, it gave me a reason to turn on the TV!
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: go4mars on 04/23/2013 04:13 AM
http://www.thespacereview.com/article/2277/1

New article from Jeff. 

Spoiler alert: 




sunburns/burnt peeling skin on local. 
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: go4mars on 05/14/2013 03:35 AM
there is no case in the entire recorded history of meteorite tsunami.
Does Burckle crater not count?
Of course, it does not  :)
I am talking about historical records and about events

Exodus 14:19-29 "pillar of cloud", water recedes, rushes back ... hey who knows?
http://www.lpi.usra.edu/meetings/lpsc2009/pdf/2243.pdf
It seems strange to me that no one has sent a boat out there for some samples.  Burckle crater, if characterized better, could have some really signifcant implications for many fields, archeology being a biggy. 

In concert with stuff like this:  http://forum.nasaspaceflight.com/index.php?topic=31118.msg1022991#msg1022991

There could be a re-think on frequency of larger events, damage potential of larger bollides, a careful look at certain orbits, and an acceleration of our tracking capability for "hazards" that are 15 meters or less.   

If I had less responsibilities, I'd strongly consider doing a PhD on this subject.  Maybe when I'm an empty-nester.           It might fit in well with retirement ambitions of field work on Mars.   
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: iamlucky13 on 05/17/2013 03:46 AM
sunburns/burnt peeling skin on local. 

I've not read of any related claims.

But it looked like a mostly clear day, and even the winter sun can still potentially cause a nasty burn if you're pasty white from staying inside all winter, and then spend several hours staring up at the dissipating smoke trail and wondering at what happened.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: go4mars on 05/27/2013 03:13 AM
I'm not aware of any threads specifically for the Holocene/Younger Dryas impact ideas.  I assume people interested in that would probably click on this thread.  The comment section for this article has a lot of interesting thoughts related to fairly large, fairly recent impacts (regionally catastrophic):

http://wattsupwiththat.com/2013/05/24/where-lies-the-younger-dryas-smoking-gun/#more-86924

like this link:
http://cometstorm.wordpress.com/2011/04/27/a-different-kind-of-climate-catastrophe-2/
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: JohnFornaro on 05/31/2013 01:46 PM
Thanks for the learn something new every day moment with the link to WUWT.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Targeteer on 08/27/2013 06:40 AM
The meteor showed heating from some previous encounter(s) before finally meeting it's end.

http://news.yahoo.com/russian-meteor-explosion-space-rock-had-near-misses-222044770.html
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: go4mars on 08/27/2013 01:49 PM
Interesting article.  I suspect the author was a little confused about the mechanism for increased concentration of platinum group metals in the fusion crust.  It isn't called a fusion crust because of nuclear fusion!! 
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: kevin-rf on 08/27/2013 03:13 PM
It isn't called a fusion crust because of nuclear fusion!! 
IF the earlier melt was from getting to close to the sun, technically...

Very, Very interesting none the less.

Btw. Where in the article do you seem them mentioning nuclear fusion? I just re-read it three times and don't see it.
Quote
"We think the appearance (formation) of this platinum group mineral in the fusion crust may be linked to compositional changes in metal-sulfide liquid during remelting and oxidation processes as the meteorite came into contact with atmospheric oxygen."
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: go4mars on 08/27/2013 08:12 PM
Where in the article do you seem them mentioning nuclear fusion? I just re-read it three times and don't see it.

Unless the article changed, I must have read it too fast.  You're right.  Maybe I thought the implication was elements that formed on entry (because he mentions elements of the alloy as opposed to a mineral name or something).  No concentrations given. 

Quote
Another surprise finding from the Chelyabinsk meteorites came from their fusion crusts. There, researchers found small amounts of platinum-group elements, in the form of an alloy of osmium, iridium and platinum, that are rare in this layer of meteorites. The scientists think these may have formed when the falling rocks slam into Earth's atmosphere.
  He switches from "an alloy" to the word "these".  Does these mean "these elements"?  Or "these alloys".  Maybe that was where the horse bucked me. 

In a fluidized hot sand bed, where coke rinds on grains are burned, nickel and vanadium are left as a deposit on the grains in a process like this:
http://www.ivanhoeenergy.com/index.php?page=htl_process_overview

I wonder if that's analogous. 
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Targeteer on 09/05/2013 11:27 PM
Largest fragment yet confirmed

http://www.spacedaily.com/reports/Largest_Piece_So_Far_of_Chelyabinsk_Meteorite_Found_999.html
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Targeteer on 09/30/2013 04:24 AM
A bigger piece yet

http://www.spacedaily.com/reports/Divers_recover_10_12-pound_meteorite_fragment_from_lake_in_Urals_999.html
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Targeteer on 10/09/2013 01:54 AM
analysis of the recovered pieces

http://earthsky.org/space/insights-from-space-rocks-left-after-meteor-exploded-over-russia
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Artyom. on 10/16/2013 11:11 AM
Chelyabinsk researchers get 11-kilo fragment of Chebarkul meteorite

http://voiceofrussia.com/news/2013_10_16/Chelyabinsk-researchers-get-11-kilo-fragment-of-Chebarkul-meteorite-4602/
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Artyom. on 10/16/2013 11:11 AM
Biggest chunk of Russian meteorite lifted from lakebed


http://rt.com/news/largest-fragment-meteorite-lifted-258/
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: TomH on 10/16/2013 09:32 PM
Washington Post is reporting a 570 kilo chunk recovered:

http://www.washingtonpost.com/world/europe/scientists-find-570-kilo-1256-pound-chunk-of-chelyabinsk-meteor-on-bottom-of-russian-lake/2013/10/16/c2a88b38-366f-11e3-89db-8002ba99b894_story.html
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: kevin-rf on 10/16/2013 10:59 PM
I suspect that is the pebble pictured above ...
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Danderman on 10/16/2013 11:44 PM
or, it is some random rock that happened to be under water the other day.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Silmfeanor on 10/17/2013 12:04 AM
or, it is some random rock that happened to be under water the other day.

Please, did you even read the article?

Quote
Sergei Zamozdra, an associate professor at Chelyabinsk State University, told Russian television the excavated fragment was definitely a chunk of the meteorite.

So unless you have a credible source that says otherwise....
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: go4mars on 10/17/2013 04:51 AM
The huge hole in the ice strongly implied this should happen.  Delightful that they got it!  Good work.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: kevin-rf on 10/17/2013 03:09 PM
More glad it was intact, and did not shatter on impacting the ice! Guess the meteor was tougher than Russian Ice!

So if the recovered fragment was 570 kg and the parent an estimated 11,000 tonnes they just recovered 0.005%
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Mader Levap on 10/17/2013 07:22 PM
or, it is some random rock that happened to be under water the other day.
Yes, because geologists are idiots that cannot tell apart one rock from another.

Nice troll, BTW.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: kevin-rf on 10/17/2013 07:27 PM
You know you could always drop a rock on the troll ;)
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Ben the Space Brit on 10/17/2013 08:01 PM
The mineralogical analysis should be interesting: Was is metal (if so, which) or silicate?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: hop on 10/17/2013 08:48 PM
The mineralogical analysis should be interesting: Was is metal (if so, which) or silicate?
Many fragments have already be recovered and analyzed.  It is classified as an ordinary chondrite. It is unlikely the big chunk will be much different.

See
http://en.wikipedia.org/wiki/Chelyabinsk_meteorite

http://link.springer.com/article/10.1134%2FS0016702913070100
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: ClaytonBirchenough on 10/17/2013 10:00 PM
Is the meteorite 570 kg? I was reading that the scale they originally weighed it on broke at this weight...
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Targeteer on 10/22/2013 01:40 PM
Determining the orbit from satellite images of the re-entry

http://phys.org/news/2013-10-scientists-satellites-captured-chelyabinsk-meteor.html
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Targeteer on 11/06/2013 08:21 PM
RELEASE 13-327 
   
 NASA and International Researchers Obtain Crucial Data from Meteoroid Impact 
 
A team of NASA and international scientists for the first time have gathered a detailed understanding of the effects on Earth from a small asteroid impact. 

The unprecedented data obtained as the result of the airburst of a meteoroid over the Russian city of Chelyabinsk on Feb. 15, has revolutionized scientists' understanding of this natural phenomenon.

The Chelyabinsk incident was well observed by citizen cameras and other assets. This factor provided a unique opportunity for researchers to calibrate the event, with implications for the study of near-Earth objects (NEOs) and the development of hazard mitigation strategies for planetary defense. Scientists from nine countries now have established a new benchmark for future asteroid impact modeling. 

"Our goal was to understand all circumstances that resulted in the shock wave," said meteor expert Peter Jenniskens, co-lead author of a report published in the journal Science.

Jenniskens, a meteor astronomer at NASA’s Ames Research Center and the SETI Institute, participated in a field study led by Olga Popova of the Institute for Dynamics of Geospheres of the Russian Academy of Sciences in Moscow in the weeks following the event.

“It was important that we followed up with the many citizens who had firsthand accounts of the event and recorded incredible video while the experience was still fresh in their minds," said Popova. 

By calibrating the video images from the position of the stars in the night sky, Jenniskens and Popova calculated the impact speed of the meteor at 42,500 mph (19 kilometers per second). As the meteor penetrated through the atmosphere, it fragmented into pieces, peaking at 19 miles (30 kilometers) above the surface. At that point the superheated meteor appeared brighter than the sun, even for people 62 miles (100 kilometers) away.

Because of the extreme heat, many pieces of the meteor vaporized before reaching Earth. Scientists believe that between 9,000 to 13,000 pounds (4,000 to 6,000 kilograms) of meteorites fell to the ground. This amount included one fragment weighing approximately 1,400 pounds (650 kilograms). This fragment wasrecovered from Lake Chebarkul on Oct. 16 by professional divers guided by Ural Federal University researchers in Yekaterinburg, Russia.

NASA researchers participating in the 59 member consortium study suspect the abundance of shock fractures in the rock contributed its breakup in the upper atmosphere. Meteorites made available by Chelyabinsk State University researchers were analyzed to learn about the origin of the shock veins and their physical properties. Shock veins are caused by asteroid collisions. When asteroid collide with each other, heat generated by the impact causes iron and nickel components of the objects to melt. These melts cool into thin masses, forming metal veins – shock veins – in the objects.

"One of these meteorites broke along one of these shock veins when we pressed on it during our analysis," said Derek Sears, a meteoriticist at Ames.

Mike Zolensky, a cosmochemist at NASA’s Johnson Space Center in Houston, may have found why these shock veins (or shock fractures), were so frail. They contained layers of small iron grains just inside the vein, which had precipitated out of the glassy material when it cooled.

"There are cases where impact melt increases a meteorite's mechanical strength, but Chelyabinsk was weakened by it," said Zolensky.

The impact that created the shock veins may have occurred as long ago as 4.4 billion years. This would have been 115 million years after the formation of the solar system, according to the research team, who found the meteorites had experienced a significant impact event at that time.

“Events that long ago affected how the Chelyabinsk meteoroid broke up in the atmosphere, influencing the damaging shockwave,” said Jenniskens.

NASA’s Near-Earth Object Program sponsors research to better understand the origin and nature of NEOs. These essential studies are needed to inform our approach to preparing for the potential discovery and deflection of an object on a collision course with the Earth.

NASA's recently announced asteroid initiative includes the first mission to capture and relocate an asteroid, as well as a grand challenge to find and characterize all asteroid threats to human population. It represents an unprecedented technological feat that will lead to new scientific discoveries and technological capabilities that will help protect our home planet.

Aside from representing a potential threat, the study of asteroids and comets represent a valuable opportunity to learn more about the origins of our solar system, the source of water on the Earth, and even the origin of organic molecules that lead to the development of life.

For more information about the Chelyabinsk field study visit:

http://cams.seti.org/index-chelyabinsk.html

For more information on asteroids and comets, visit:

http://www.nasa.gov/asteroids
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Star One on 11/06/2013 08:28 PM
Reported on BBC news. So an early warning system is needed, didn't we just discontinue one of those.

Quote
The threat of another asteroid strike like the one that hit Russia earlier this year is much higher than was previously thought, a study suggests.

Researchers have found that space rocks of a similar size to the one that exploded over Chelyabinsk are hurtling into the Earth's atmosphere with surprising frequency.

Scientists say early warning systems need to be put in place.

http://www.bbc.co.uk/news/science-environment-24839601
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Ben the Space Brit on 11/07/2013 11:17 AM
Purely for completeness, according to a study reported in The Daily Mail (http://www.dailymail.co.uk/sciencetech/article-2488478/Russias-meteor-explosion-powerful-400-000-tonnes-TNT.html), the explosion of the bolide was about equivalent to 400kt of TNT.

We should be grateful it happened in the mesosphere; one doesn't want to contemplate what would have happened if it had detonated at a lower altitude over a population centre.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: kevin-rf on 11/07/2013 12:13 PM
A little off topic, but a bright fireball lit up Southern California last night:

(Discovery channel has a video)

http://news.discovery.com/space/asteroids-meteors-meteorites/possible-taurid-fireball-dazzles-southern-california-131107.htm
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Rocket Science on 11/07/2013 03:06 PM
A little off topic, but a bright fireball lit up Southern California last night:

(Discovery channel has a video)

http://news.discovery.com/space/asteroids-meteors-meteorites/possible-taurid-fireball-dazzles-southern-california-131107.htm
Neil deGrasse Tyson was talking about both events on CNN this morning and about deflecting objects for Earth defense...
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: PahTo on 11/07/2013 03:10 PM

Article in this morning's SeattleTimes about planetary defense as well...

http://seattletimes.com/html/nationworld/2022206844_asteroidrisksxml.html
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: kevin-rf on 11/07/2013 06:00 PM
At least we have some good news today:

http://www.slate.com/blogs/bad_astronomy/2013/11/07/good_asteroid_news_tv135_no_longer_a_threat.html

Quote
After writing about small impacts being more common than we previously thought, I have some good news: The chance of an impact from the newly-discovered asteroid 2013 TV135 have dropped to essentially zero.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: MP99 on 11/07/2013 09:09 PM
A little off topic

Nope. Mods have merged BBC article into this thread (#541), so bang-on-topic.



but a bright fireball lit up Southern California last night...

Cheers, Martin
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Melt Run on 11/07/2013 09:35 PM
At least we have some good news today:

http://www.slate.com/blogs/bad_astronomy/2013/11/07/good_asteroid_news_tv135_no_longer_a_threat.html

Quote
After writing about small impacts being more common than we previously thought, I have some good news: The chance of an impact from the newly-discovered asteroid 2013 TV135 have dropped to essentially zero.
And the bad news is:
http://www.theregister.co.uk/2013/11/06/chelyabinsksized_meteors_impacts_seven_times_more_common_than_first_thought/
Well you can't win all of them. I may get up in the middle of the night tonight but it won't be because I'm worrying about this!
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: kevin-rf on 11/07/2013 09:54 PM
I miss the hot tub... nothing like sitting out in the middle of the night watching them zip by... Oh well, just waiting for a delivery date on the replacement.

A really bright light in the world of instant information, instant analysis, instant gratification is NASA's All Sky Fireball Network (bottom of the http://spaceweather.com page) that strives to model the orbits of fireballs it see's each night.

http://fireballs.ndc.nasa.gov/

Always want'd a dome camera like that. It would be great for tracking meteor's and bright satellite.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Danderman on 04/19/2014 04:21 PM
http://www.youtube.com/watch?v=_EcjeFqxv6Y

A near miss last night over Murmansk.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: ugordan on 04/19/2014 04:29 PM
A near miss last night over Murmansk.

Nice find, but "a near miss"? That looked like your typical bolide, far from a Chelybinsk scale event.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Prober on 04/19/2014 04:53 PM
A near miss last night over Murmansk.

Nice find, but "a near miss"? That looked like your typical bolide, far from a Chelybinsk scale event.

I hope we can get more videos out to see.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Danderman on 04/19/2014 07:46 PM
A near miss last night over Murmansk.

Nice find, but "a near miss"? That looked like your typical bolide, far from a Chelybinsk scale event.

Impossible to tell from one point of view. If there were multiple videos, someone could calculate the trajectory.

This could be a low flying speck of dust, or a high flying asteroid.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: kevin-rf on 04/19/2014 07:50 PM
The linked video had the view from two different dash cams. They now just need to locate where the dash cams when when they recorded the event. Considering the date code on the first is 4/19/2014 I am sure more will turn up.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: ugordan on 04/19/2014 07:57 PM
Impossible to tell from one point of view.

Well, not really. Good educated guesses can still be made. From the brightness and duration profile we can be pretty sure that it was a fairly small object that got disintegrated fast, although possibly with recoverable fragments on the ground. This is night footage where camera exposure is longer making objects appear brighter and yet the bolide didn't really turn "night into day". This suggests this object is many times smaller than Chelyabinsk. No sonic booms heard is another good clue about the magnitude of the event.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: go4mars on 04/20/2014 12:54 AM
Impossible to tell from one point of view.

Well, not really. Good educated guesses can still be made. From the brightness and duration profile we can be pretty sure that it was a fairly small object that got disintegrated fast, although possibly with recoverable fragments on the ground. This is night footage where camera exposure is longer making objects appear brighter and yet the bolide didn't really turn "night into day". This suggests this object is many times smaller than Chelyabinsk. No sonic booms heard is another good clue about the magnitude of the event.
I'm sure the infrasound folks have a very clear idea of magnitude (energy/duration), but I'm pretty sure that dataset remains classified.  But yeah, I'm sure guys like Alan Hildebrand are already refining P10 P50 P90 with every new dashcam view.  Frame by frame. 
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Targeteer on 05/27/2014 06:31 PM
http://www.spacedaily.com/reports/Chelyabinsk_meteorite_part_of_much_bigger_celestial_body_999.html

Jade was the key...
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Ben the Space Brit on 05/28/2014 06:04 PM
I think this theory is supported by the fact that the meteor's predicted orbit started in the Main Belt. It was probably knocked off of a parent body there by a collision, probably with a long-period comet.

I wonder if there are any other significant bodies on the same orbital track, waiting for their moment?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Stellar_Speedster on 11/11/2014 05:46 AM
I think this theory is supported by the fact that the meteor's predicted orbit started in the Main Belt. It was probably knocked off of a parent body there by a collision, probably with a long-period comet.

I wonder if there are any other significant bodies on the same orbital track, waiting for their moment?

Exactly what I tought about it. Did this come in unnotissed ?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Kryten on 11/11/2014 03:17 PM
I think this theory is supported by the fact that the meteor's predicted orbit started in the Main Belt. It was probably knocked off of a parent body there by a collision, probably with a long-period comet.

I wonder if there are any other significant bodies on the same orbital track, waiting for their moment?

Exactly what I tought about it. Did this come in unnotissed ?
Only two bodies have ever been noticed before impacting earth; one that hit an uninhabited bit of Sudan in 2008 (2008 TC3), and another that impacted somewhere in the atlantic earlier this year (2014 AA).
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: kevin-rf on 11/14/2014 11:46 PM
JPL just released the data set on all the large impacts detected during the last 20 years. 556 in all. One can assume this is the declassified IR early warning satellite (DSP, SBIRS) data set.

http://www.jpl.nasa.gov/news/news.php?feature=4380

Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: kevin-rf on 11/15/2014 12:02 AM
Better press release: http://neo.jpl.nasa.gov/news/news186.html

Interesting that there is a slight gap above the Amazon, while slightly larger numbers where detected over Siberia and China. Anyone want to go all tinfoil and argue it is because there are no ICBM's in South America and it is not as well covered?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: aceshigh on 11/15/2014 10:19 AM
Better press release: http://neo.jpl.nasa.gov/news/news186.html

Interesting that there is a slight gap above the Amazon, while slightly larger numbers where detected over Siberia and China. Anyone want to go all tinfoil and argue it is because there are no ICBM's in South America and it is not as well covered?

actually, the whole brazilian territory is free of impacts on this map, not only the amazon.

Edit: actually, there is one on Amapá state, then on the coasts of Pernambuco and Rio Grande do Norte, and also off the coast of Santa Catarina in the south. But apparently in LAND, only at Amapá state.
(http://i.imgur.com/QAcbsl7.jpg)
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Wicky on 11/15/2014 01:03 PM
So we can sumise that the Brazillians are in cahoots with the Martians...
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: pagheca on 11/15/2014 09:52 PM
Obviously, this doesn't make sense without a numerical statistical analysis.

p.s. It's something similar to the V-2 target claim over London and it may be a nice undergrad exercise for statistics students...

p.p.s. I guess the probability of an event is linear with his energy in bilogaritmic scale. So, the events at 1 GJ (that's the energy to evaporate less then 1/2 m3 of water, just to give an idea) are way too little in the map. That means that the detector was not very sensitive at that energy and the map may be biased toward more powerful events.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: francesco nicoli on 11/15/2014 10:11 PM
Italy is free too, but I saw with my eys a big fireball bolid in 2009 above the skies of the Emilian flats.....
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: kevin-rf on 11/16/2014 01:56 AM
I think a better way is map what DSP's where in orbit during the period and see if anything thing stands out, like fewer satellites covering america or such, maybe a Brazil is half way between two of them.

The data is missing several things.
1. A data table with the date/time of events.
2. An indication if the lower limit is the same across the globe. Or different satellites from different generations have different lower limits.

I think this part of why the DOD has been so resistant to release the data. It may show the lower detection limits of the system and may indicate that global coverage is not 100%. 

For instance, Brazil most likely does not need to be high on the monitoring list since they lack ICBM's and are relatively stable. Or this could just be a statistical fluke.

You need to cover the oceans, North America, Cuba, Russia, China, Europe for obvious reasons. It makes sense to cover Africa and the Middle East due to how "Stable" the regions are. Australia is a close ally.

So the only region that does not need heavy coverage is Brazil, and maybe Antarctica.  Odd the map has a hole in Brazil. 

It also reminds me of something. When Mars 96 failed, US Space Command thought it ended up in the Pacific, but decided  later based on media reports of eye witness accounts it reentered over Bolivia / Chili.  This begs a question, how was that missed if 24/7 100% coverage was being provided.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: NovaSilisko on 11/16/2014 02:18 AM
... or it could just be the inherent human penchant for recognizing patterns when presented with random data.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: hop on 11/16/2014 02:32 AM
I think a better way is map what DSP's where in orbit during the period and see if anything thing stands out, like fewer satellites covering america or such, maybe a Brazil is half way between two of them.
Better, start with some statistical tests to see whether the distribution is compatible with random events.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: Stellar_Speedster on 11/16/2014 06:30 AM
Better press release: http://neo.jpl.nasa.gov/news/news186.html

Interesting that there is a slight gap above the Amazon, while slightly larger numbers where detected over Siberia and China. Anyone want to go all tinfoil and argue it is because there are no ICBM's in South America and it is not as well covered?

Red areas are also ICBM sites ?
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: MP99 on 11/16/2014 08:33 AM


Better press release: http://neo.jpl.nasa.gov/news/news186.html

Interesting that there is a slight gap above the Amazon, while slightly larger numbers where detected over Siberia and China. Anyone want to go all tinfoil and argue it is because there are no ICBM's in South America and it is not as well covered?

I want to know what they're hiding at the poles, since they're less impacted.

Cheers, Martin

PS http://www.youtube.com/watch?v=OH1bZ0F3zVU
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: pagheca on 11/16/2014 08:35 AM
I want to know what they're hiding at the poles, since they're less impacted.

Lots of meteorites. Trust me (http://en.wikipedia.org/wiki/ANSMET). ;)
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: MP99 on 11/16/2014 09:16 AM
I want to know what they're hiding at the poles, since they're less impacted.

Lots of meteorites. Trust me (http://en.wikipedia.org/wiki/ANSMET). ;)

Not sure if you got the video? :-)

Cheers, Martin
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: aceshigh on 11/16/2014 12:06 PM
So we can sumise that the Brazillians are in cahoots with the Martians...

ever heard about the Varginha ET?

and the flying saucer landing strip in the savannah near Brasilia, where a community of UFO believers built pyramid shaped houses?

Coincidence? I think not.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: the_other_Doug on 11/16/2014 04:34 PM
So we can sumise that the Brazillians are in cahoots with the Martians...

ever heard about the Varginha ET?

and the flying saucer landing strip in the savannah near Brasilia, where a community of UFO believers built pyramid shaped houses?

Coincidence? I think not.


AAAAAAARRRRRRRRGGGHHH!!!!!!!!!!!!!

I may not be able to wipe that pseudo-science crap off of TV, but oughtn't we be able to come to this enclave of scientific rationalism, here, and not risk being assaulted by that freaking-idiot-with-the-pubic-hair-on-his-head from Ancient Aliens?

I guess the answer is obvious...

I THINK NOT!!!!!

sigh

-Doug  (With my shield, and aiming at that pseudo-science idiot with my spear)
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: robertross on 11/16/2014 04:56 PM
Something very cool that caught my attention, and thought I would share.

What happens to the gas released when the meteorite vapourizes?

http://www3.imperial.ac.uk/earthscienceandengineering/aboutese/hottopic/pasttopics/meteorite%20gas

Quote
The researchers used a technique called pyrolysis-FTIR, which rapidly heats the fragments at a rate of 20,000 degrees Celsius per second, and they then measured the gases released.

They found that on average, each meteorite was capable of releasing up to 12 percent of the meteorites’ mass as water vapour and 6 percent of the meteorites’ mass as carbon dioxide when entering an atmosphere. They concluded that contributions from individual meteorites were low small and were unlikely to have a significant impact on the atmospheres of planets on their own.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: the_other_Doug on 11/16/2014 08:24 PM
The linked article seems to assume that *all* meteorites are relatively volatile-rich.  While most meteorites are chondritic, only a fairly small percentage of those are even characterized as containing a "small amount" of volatiles.

Even the article's inset states that "some meteorites contain abundant water and organics" (emphasis mine).  And yet the article seems to ignore this.

I'm thinking the actual research is figuring in the observed abundances to their results, and it's just the "journalist" who is ignoring them.

-Doug  (With my shield, not yet upon it)
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: kevin-rf on 11/17/2014 12:22 AM
Water, water everywhere... seems every time we kick over a rock it goes splash!!!
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: aceshigh on 11/21/2014 11:29 PM
So we can sumise that the Brazillians are in cahoots with the Martians...

ever heard about the Varginha ET?

and the flying saucer landing strip in the savannah near Brasilia, where a community of UFO believers built pyramid shaped houses?

Coincidence? I think not.


AAAAAAARRRRRRRRGGGHHH!!!!!!!!!!!!!

I may not be able to wipe that pseudo-science crap off of TV, but oughtn't we be able to come to this enclave of scientific rationalism, here, and not risk being assaulted by that freaking-idiot-with-the-pubic-hair-on-his-head from Ancient Aliens?

I guess the answer is obvious...

I THINK NOT!!!!!

sigh

-Doug  (With my shield, and aiming at that pseudo-science idiot with my spear)

I am brazilian, to the Varginha ET nonsense is something I know from the news back in the day, not from the imbecile documentaries of what USED to be history and science channels.

Anyway, I only mentioned it joking of course, in response to the joke about brazilians being in cahoots with Martians.

Don´t worry. I don´t believe in UFOs (at least, not in UFOs that transverse light years to crash on Earth due to malfunction or puny human missiles, or that are sighted (how careless, even human armies have better anti-radar tech AND can be less visible), nor aliens that suspiciously look quite a lot like human fetuses, which would indicate they also evolved from monkeys, and those monkeys from other mammals, and those mammals from synapsides, and so on...
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: baldusi on 11/25/2014 04:56 PM
I just have to add this paper. For their sample, impact are not uniformly random. It seems that they are correlated to Jupiter's perturbations, for example.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: go4mars on 11/25/2014 05:15 PM
Italy is free too, but I saw with my eys a big fireball bolid in 2009 above the skies of the Emilian flats.....
Similarly, I saw one in 1995 in Kananaskis that also isn't on there.  Perhaps it was too small?  For better or worse, I'm not an expert in 'eyeball calibrations' of multi-GigaJoule visual spectrum events.  ;~/
But I would have guessed it should make the list. 

 
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: go4mars on 11/25/2014 05:22 PM
I just have to add this paper. For their sample, impact are not uniformly random. It seems that they are correlated to Jupiter's perturbations, for example.
Thanks for the paper.  After a quick scan, here's a once sentence quote. "The overall impact risk for the Southern hemisphere is 50 percent higher than that of the Northern hemisphere from September to December."   

I haven't calculated it (would be complicated given the relative speeds and geometry), but given the 23.5 degree axial tilt, 50% more likelihood seems intuitively reasonable during the part of the orbit that the planet travels more bottom-first.  What's unusual is that the northern hemisphere didn't show the same thing.
Title: Re: Meteor Strikes Chelyabinsk, Russia
Post by: kevin-rf on 11/25/2014 07:15 PM
Might I offer a plausible explanation, Kreutz Sungrazers. http://en.wikipedia.org/wiki/Kreutz_Sungrazers

It might be plausible if something in the Oort locally is perturbing orbits and sending them sun ward. If that is happening they will be heading in from a similar section of the sky and crossing earths orbit on the way out at roughly the same time and from the same southern direction year after year.