Author Topic: Meteor Strikes Chelyabinsk, Russia  (Read 136506 times)

Offline JohnFornaro

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #400 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.
Sometimes I just flat out don't get it.

Offline go4mars

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #401 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.  :)
« Last Edit: 02/20/2013 04:06 PM by go4mars »
Elasmotherium; hurlyburly Doggerlandic Jentilak steeds insouciantly gallop in viridescent taiga, eluding deluginal Burckle's abyssal excavation.

Offline JohnFornaro

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #402 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.

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Sometimes I just flat out don't get it.

Offline go4mars

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #403 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.
Elasmotherium; hurlyburly Doggerlandic Jentilak steeds insouciantly gallop in viridescent taiga, eluding deluginal Burckle's abyssal excavation.

Offline AJW

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #404 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.

Offline ugordan

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #405 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.
« Last Edit: 02/20/2013 05:35 PM by ugordan »

Offline AJW

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #406 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.

Offline ugordan

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #407 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...

Offline iamlucky13

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #408 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.

Offline JohnFornaro

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #409 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.
« Last Edit: 02/21/2013 02:24 AM by JohnFornaro »
Sometimes I just flat out don't get it.

Offline AJW

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #410 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.

Online catdlr

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #411 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.

Tony De La Rosa

Offline rickl

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #412 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.
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Offline Hyperion5

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #413 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

Offline Archibald

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #414 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

Offline 360-180

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #415 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

Offline aquanaut99

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #416 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!

Offline jcm

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #417 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.
-----------------------------

Jonathan McDowell
http://planet4589.org

Offline R7

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #418 on: 02/21/2013 01:17 PM »
"In Chelyabinsk you hit the meteorite."
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Offline Prober

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #419 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.
 
 
 
 
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