Author Topic: Meteor Strikes Chelyabinsk, Russia  (Read 140853 times)

Offline Dalhousie

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #20 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?
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Online Ben the Space Brit

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #21 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.
« Last Edit: 02/15/2013 10:25 AM by Ben the Space Brit »
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Offline Robotbeat

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #22 on: 02/15/2013 10:23 AM »
If you listened to the videos, though, you can hear what sound like air defense weapons.
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Offline mmeijeri

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #23 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?
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Offline R7

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #24 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.
« Last Edit: 02/15/2013 10:47 AM by R7 »
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Offline smoliarm

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #25 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
!
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.

Offline Dalhousie

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #26 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.
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Offline Dalhousie

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #27 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.

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Offline mmeijeri

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #28 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.
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Offline smoliarm

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #29 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/



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


Offline aquanaut99

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #30 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.

Offline R7

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #31 on: 02/15/2013 11:07 AM »
Found the original itar-tass article about size

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

edit: if there were SAM activity there would have been contrails, no?
« Last Edit: 02/15/2013 11:10 AM by R7 »
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Online Ben the Space Brit

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #32 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.
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Offline aquanaut99

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #33 on: 02/15/2013 11:10 AM »
Found the original itar-tass article about size

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

Hey, thanks! Looks like my yield guess was pretty close...  :D

Offline mmeijeri

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #34 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.
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Offline R7

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #35 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! ::)





« Last Edit: 02/15/2013 11:41 AM by R7 »
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Offline tigerade

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #36 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.

Offline smoliarm

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #37 on: 02/15/2013 11:32 AM »
Found the original itar-tass article about size

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 :)

Offline Star One

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #38 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?

Offline douglas100

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #39 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.
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