Author Topic: Meteor Strikes Chelyabinsk, Russia  (Read 136638 times)

Online ugordan

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #340 on: 02/18/2013 12:06 PM »
You are hugely underestimating the resiliency of birds.

Offline 360-180

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #341 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
 
« Last Edit: 02/18/2013 12:31 PM by 360-180 »

Offline sanman

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #342 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.



« Last Edit: 02/18/2013 01:23 PM by sanman »

Offline JohnFornaro

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #343 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.
Sometimes I just flat out don't get it.

Offline JimO

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #344 on: 02/18/2013 02:42 PM »

Offline Robotbeat

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #345 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.
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Offline JimO

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #346 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?

Offline edkyle99

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #347 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.

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Offline Robotbeat

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #348 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.
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Offline JohnFornaro

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #349 on: 02/18/2013 04:03 PM »
JimO:  Thanks!
Sometimes I just flat out don't get it.

Offline 360-180

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #350 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
« Last Edit: 02/18/2013 04:40 PM by 360-180 »

Offline Warren Platts

Re: Meteor Strikes Chelyabinsk, Russia
« Reply #351 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.
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Offline iamlucky13

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #352 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.

Offline rdale

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #353 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.

Offline iamlucky13

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #354 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.

Offline Mongo62

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #355 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.
« Last Edit: 02/18/2013 06:44 PM by Mongo62 »

Offline kevin-rf

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« Last Edit: 02/18/2013 06:34 PM by kevin-rf »
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Offline Blackstar

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #357 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.

Offline Warren Platts

Re: Meteor Strikes Chelyabinsk, Russia
« Reply #358 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 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.
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Offline R7

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Re: Meteor Strikes Chelyabinsk, Russia
« Reply #359 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?
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