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Author Topic: Meteorite fall in Chelyabinsk!  (Read 3571 times)

Offline Muncha

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Meteorite fall in Chelyabinsk!
« on: 15/02/2013 06:22:48 »
Today registered a decline metiarita! Flash seen for 300 miles! Does not work mobile. There are wounded from cuts of broken glass! The evening will fly folder, NASA will be broadcast live!

Here is video:


 

Offline CliffordK

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Re: Meteorite fall in Chelyabinsk!
« Reply #1 on: 15/02/2013 18:19:57 »
There is already a Wikipedia Page

I had thought that it was a strange coincidence that on the same day a 50 meter asteroid was predicted to pass below several communication satellites, an unseen, although somewhat smaller asteroid actually strikes Earth.

It is a harsh reminder of how much more work we have on our asteroid detection and NEO prediction system.
 

Offline David Cooper

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Re: Meteorite fall in Chelyabinsk!
« Reply #2 on: 15/02/2013 20:50:35 »
I've been worrying about glass windows for a long time because of the Tunguska event. Good to see that no one's been killed by glass in this incident today. Maybe we should all get the sellotape out and stick transparent Xs on all our windows.
 

Offline CliffordK

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Re: Meteorite fall in Chelyabinsk!
« Reply #3 on: 15/02/2013 20:55:11 »
Of course we have the ability to make glass that can stop a speeding bullet. 

The flash would have preceded the sonic boom by a second, or a couple of seconds.  Just enough time for people to run to their windows and look out.

If an event occurs that is capable of flattening trees, the best place to be would be already sitting in an underground bunker.  With a pre-warning, one might be able to react.  Without a warning, one would have to be living expecting the event every day. 

The number of deaths due to meteorite impacts during the last century have been very very low.  Perhaps if one ranked all causes of deaths, it would rank at the bottom.

Of course, a big event in the wrong place could be worse than dropping a nuclear bomb in the middle of a large city.
« Last Edit: 15/02/2013 21:04:07 by CliffordK »
 

Offline David Cooper

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Re: Meteorite fall in Chelyabinsk!
« Reply #4 on: 15/02/2013 21:39:42 »
They had a couple of minutes after the flash before the bang. That means it happened somewhere between 20 and 25 miles away, with the thing ripping itself to bits perhaps seven miles or so above the ground. A lot of people would have been standing looking out at the smoke trail in the sky from their windows.
 

Offline yor_on

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Re: Meteorite fall in Chelyabinsk!
« Reply #5 on: 16/02/2013 10:46:16 »
It is mind blowing to see.
==

Now I'm just waiting to see if someone, somewhere, will suggest an attack from Outer Space :)
Tin (foil) hats on.

Start your propellers gentlemen.
« Last Edit: 16/02/2013 10:51:02 by yor_on »
 

Offline David Cooper

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Re: Meteorite fall in Chelyabinsk!
« Reply #6 on: 16/02/2013 20:02:25 »
They're now saying it exploded 35 miles up, so that would mean the delay between seeing and hearing it should have been three minutes, or nearer four if you're looking up at it at forty five degrees (which appears to be roughly the case from some of those video clips on the news - I misjudged them before as they were using wider-angle lenses than I'd thought when I first saw them). Anyway, if you see one of these things, get well away from the windows.
 

Offline CliffordK

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Re: Meteorite fall in Chelyabinsk!
« Reply #7 on: 17/02/2013 07:08:20 »
Thanks for correcting the time, assuming the shock wave was traveling at near the speed of sound.

3 minutes seems like an awful long time to be staring out the window.  But, I wonder how many of the injured people were observing the flash of light and the aftermath when the shockwave struck.

I'm glad to hear that the number of hospitalizations were low, and so far no deaths directly related to the impact.
 

Offline graham.d

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Re: Meteorite fall in Chelyabinsk!
« Reply #8 on: 17/02/2013 09:02:48 »
I spent several weeks in Chelyabinsk about 40 years ago. If I'd waited I could have seen this live :-)
 

Offline David Cooper

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Re: Meteorite fall in Chelyabinsk!
« Reply #9 on: 17/02/2013 19:49:02 »
3 minutes seems like an awful long time to be staring out the window.  But, I wonder how many of the injured people were observing the flash of light and the aftermath when the shockwave struck.

Over 4 minutes is more likely, but if you looked out the window and saw a smoke trail like that dominating the sky after a bright flash, I expect you'd spend a good long time looking at it wondering how the heck it got there. There would also have been people dashing off to tell others to look out, or phoning them to tell them to do so.
 

Offline simplified

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Re: Meteorite fall in Chelyabinsk!
« Reply #10 on: 23/02/2013 07:29:27 »
What has caused meteorite explosion in atmosphere?
 

Offline David Cooper

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Re: Meteorite fall in Chelyabinsk!
« Reply #11 on: 23/02/2013 18:44:28 »
What has caused meteorite explosion in atmosphere?

I posted something about this in another thread, but it should really be here, so I'll put a modified version of that here:-

An Australian by the name of Dr. Karl (who is a living scientific database) does a phone-in in the middle of the night (Radio 5, 3-4 on Thursday mornings). Last Thursday he said something very interesting about the mechanism by which asteroids/meteors burn up or explode. I'd always thought it was down to friction and heating generated from that, but with a big lump of rock that's only going to do superficial damage. He explained that it's actually pressure that tears these rocks to pieces as the rock piles into gas which builds up in front of it, compressing the rock because it's easier to do that than to get out of the way. He also said that things which we are taught are incompressible like water are actually compressible - if you smack something into water hard enough it can be compressed to 3/4 of its normal volume (I don't know if that's a limit or just an example taken from some specific experiment), but it will apply to solid things too, thereby giving an insight into what can happen when a rock slams into the atmosphere at tens of thousands of miles an hour. He didn't explain the heating mechanism, but I would imagine it comes along for free as a direct result of the compression, and it would take compression of the rock to drive it to tear itself to pieces - we're talking about a rock of ten to twenty metres across being reduced to fragments, and if it was done purely through heating the whole thing would turn into lava, but it clearly doesn't.
 

Offline simplified

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Re: Meteorite fall in Chelyabinsk!
« Reply #12 on: 25/02/2013 15:05:43 »
What has caused meteorite explosion in atmosphere?

 and if it was done purely through heating the whole thing would turn into lava, but it clearly doesn't.
Some stones can explode in a fire.I saw it,but I don't know the reason.
 

Offline CliffordK

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Re: Meteorite fall in Chelyabinsk!
« Reply #13 on: 25/02/2013 16:06:29 »
Some stones can explode in a fire.I saw it,but I don't know the reason.

Isn't moisture content one of the reasons why stones explode in the fire.

However, as far as meteorites, I would have to imagine that asteroids orbiting with an orbit near Earth's orbit would tend to be dry due to the low pressures and the sun's heat. 
Asteroids originating near Pluto, or further out, and not spending a lot of time near the sun would tend to have a higher water content.

However, if the meteorite consists mainly of water, it may be rapidly vaporized.

Many metals will also burn when heated in contact with oxygen.
 

Offline simplified

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Re: Meteorite fall in Chelyabinsk!
« Reply #14 on: 25/02/2013 17:03:21 »
Some stones can explode in a fire.I saw it,but I don't know the reason.

Isn't moisture content one of the reasons why stones explode in the fire.

However, as far as meteorites, I would have to imagine that asteroids orbiting with an orbit near Earth's orbit would tend to be dry due to the low pressures and the sun's heat. 
Asteroids originating near Pluto, or further out, and not spending a lot of time near the sun would tend to have a higher water content.

However, if the meteorite consists mainly of water, it may be rapidly vaporized.

Many metals will also burn when heated in contact with oxygen.
Yes, moisture was exploding some of my stones in fire.
Oxygen is oxidizing found  piece of the meteorite.But it can explain only superficial burning.
 

Offline simplified

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Re: Meteorite fall in Chelyabinsk!
« Reply #15 on: 05/03/2013 15:35:42 »
What has caused meteorite explosion in atmosphere?

I posted something about this in another thread, but it should really be here, so I'll put a modified version of that here:-

An Australian by the name of Dr. Karl (who is a living scientific database) does a phone-in in the middle of the night (Radio 5, 3-4 on Thursday mornings). Last Thursday he said something very interesting about the mechanism by which asteroids/meteors burn up or explode. I'd always thought it was down to friction and heating generated from that, but with a big lump of rock that's only going to do superficial damage. He explained that it's actually pressure that tears these rocks to pieces as the rock piles into gas which builds up in front of it, compressing the rock because it's easier to do that than to get out of the way. He also said that things which we are taught are incompressible like water are actually compressible - if you smack something into water hard enough it can be compressed to 3/4 of its normal volume (I don't know if that's a limit or just an example taken from some specific experiment), but it will apply to solid things too, thereby giving an insight into what can happen when a rock slams into the atmosphere at tens of thousands of miles an hour. He didn't explain the heating mechanism, but I would imagine it comes along for free as a direct result of the compression, and it would take compression of the rock to drive it to tear itself to pieces - we're talking about a rock of ten to twenty metres across being reduced to fragments, and if it was done purely through heating the whole thing would turn into lava, but it clearly doesn't.
You are right. Broken up meteorite interacts with oxygen.It creates explosion.
 

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Re: Meteorite fall in Chelyabinsk!
« Reply #15 on: 05/03/2013 15:35:42 »

 

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