Asteroids, meteors, and meteorites
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midtskogen | Date: Saturday, 16.02.2013, 15:08 | Message # 46 |
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| Quote (Tim) One of the Belgian newscasts used the picture of that burning gashole as if it was the meteor crater, bad bad bad TV-makers, check your sources! Yes. One other thing that's repeated in the news is that the collapsed factory was hit by a meteorite.
I've read today, and I assume that it's reliable, that divers have looked for the fragment that made the 6 meter hole in the lake outside Cheburlak. The lake was muddy and visibility was poor, so they found nothing. Meteorite fragments hit the ground in free fall, so there must be a fragment of some size that hit the lake in order to make a splash big enough to create a 6 meter hole. Certainly more than a few kg or it would only pinch a tiny hole or just embed itself in the ice. Above 100 kg, perhaps? But that will depend on what it's made of.
NASA now think that the meteor might have been as big as 10,000 tonnes, 17 meters in diameter and released half a megaton of energy. They seem to base that on infrasound detected around the world.
NIL DIFFICILE VOLENTI
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HarbingerDawn | Date: Saturday, 16.02.2013, 18:06 | Message # 47 |
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| Quote (midtskogen) NASA now think that the meteor might have been as big as 10,000 tonnes, 17 meters in diameter and released half a megaton of energy. I was a bit surprised to hear that at first, I had initially guessed that it was closer to 5 meters and released around 10 kilotons, which is similar to the initial Russian estimates. But I will admit that I didn't have nearly as much information as they did.
Quote (Tim) One of the Belgian newscasts used the picture of that burning gashole as if it was the meteor crater, bad bad bad TV-makers, check your sources! Fortunately, the American TV news all gave accurate information as far as I could see.
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Edited by HarbingerDawn - Saturday, 16.02.2013, 18:11 |
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midtskogen | Date: Saturday, 16.02.2013, 19:09 | Message # 48 |
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| Quote (HarbingerDawn) I was a bit surprised to hear that at first, I had initially guessed that it was closer to 5 meters and released around 10 kilotons, which is similar to the initial Russian estimates. But I will admit that I didn't have nearly as much information as they did. The initial dashcam videos were quite consistent with 10 kilotonnes or even less, I think. When you don't have all information, you need to fill out what you lack with the most probable information, and then to assume what is relatively common, something of the size that can hit earth once a year or a few years apart, is reasonable. There was already a couple of unusual things about this event: it was near a big city and just a few hours before the very close approach of an asteroid. That said, while there is a lot of information available, NASA have probably just scratched the surface, so the estimate will like change again, up or down.
NASA described the meteor as 1/3 in size of the asteroid. I think that is a pretty misleading thing to say. By 1/3 they mean the diameter, but what enters the atmosphere is three dimensional, not one dimensional, and the energy is not at all similar to what we would get if the asteroid had hit, which 1/3 suggests.
The first Russian estimate was low, 10 tonnes. But that might be Russian mentality. Official statements have to say "nothing to worry about" no matter what. They know that the public wont believe them whatever they say anyway. And if the first statements were wildly wrong, a higher official can always say that it was wrong, but we fired the official who made the statement, so all is ok now.
Russians are a bit weird. People were probably smashing their windows like mad just after the blast, hoping that they could get the government to replace their old windows that way. But I'm not sure this actually works now with communism gone?
NIL DIFFICILE VOLENTI
Edited by midtskogen - Saturday, 16.02.2013, 19:38 |
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HarbingerDawn | Date: Saturday, 16.02.2013, 19:33 | Message # 49 |
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| Quote (midtskogen) NASA described the meteor as 1/3 in size of the asteroid. I think that is a pretty misleading thing to say. By 1/3 they mean the diameter, but what enters the atmosphere is three dimensional, not one dimensional, and the energy is not at all similar to what we would get if the asteroid had hit, which 1/3 suggests. I don't think it was misleading. I have seen NASA describe the Russian bolide object as being 15 m in diameter, and 2012 DA14 as being ~45-50 m in diameter. They have never said that the difference in effects of those two impacts would scale linearly with relation to their diameter, and they've also mentioned that one had a mass of ~7,000 tons, while the other was closer to 100,000 tons. I haven't seen any NASA release where they simply said "one was 1/3 the size of the other", and even if they did it is not misleading since size is generally assumed in public discourse to refer to diameter.
You're reading too much into it.
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midtskogen | Date: Saturday, 16.02.2013, 20:14 | Message # 50 |
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| Quote (HarbingerDawn) I haven't seen any NASA release where they simply said "one was 1/3 the size of the other" I'm not finding it again, so perhaps what I read was something retelling a NASA statement. I retract my statement since I can't find a quote.
In any case it was big, perhaps the biggest known since Tunguska (but I wouldn't think it unlikely that something as big as this has hit earth a few times in the last century with few or no witnesses).
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HarbingerDawn | Date: Saturday, 16.02.2013, 20:26 | Message # 51 |
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| Quote (midtskogen) In any case it was big, perhaps the biggest known since Tunguska (but I wouldn't think it unlikely that something as big as this has hit earth a few times in the last century with few or no witnesses). Something approximately that size could be expected to hit Earth about twice each century.
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midtskogen | Date: Saturday, 16.02.2013, 21:08 | Message # 52 |
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| rt.com a little while ago: "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."
Does anyone have more on this? It's not strange that they don't find anything in a muddy lake floor (better wait for summer?) but what created the hole? Since there were blocks of ice around the hole, it can't have been formed by currents, escaping gas or similar things, so did someone do this as a joke?
NIL DIFFICILE VOLENTI
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Tim | Date: Saturday, 16.02.2013, 22:46 | Message # 53 |
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| I think it was probably a part of the meteor that fell in the water. I don't see anyone quickly going on the ice to make a fake crater when he sees a meteor coming through the atmosphere. It's proabably not easy to search for a rock in a frozen lake during a Russian winter
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HarbingerDawn | Date: Sunday, 17.02.2013, 01:23 | Message # 54 |
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| :3
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Salvo | Date: Sunday, 17.02.2013, 13:49 | Message # 55 |
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| Quote (HarbingerDawn) Image
Nice
The universe is not required to be in perfect harmony with human ambition.
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(still don't know why everyone is doing this...)
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DoctorOfSpace | Date: Sunday, 17.02.2013, 21:23 | Message # 56 |
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| Was sent this over steam last night
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HarbingerDawn | Date: Sunday, 17.02.2013, 21:24 | Message # 57 |
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| Doc, http://en.spaceengine.org/forum/23-1221-20141-16-1361080126
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DoctorOfSpace | Date: Sunday, 17.02.2013, 21:55 | Message # 58 |
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You depress me
I only just checked.
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Solaris | Date: Monday, 18.02.2013, 20:24 | Message # 59 |
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| Nice video of Asteroid 2012 DA 14 featured on the APOD :
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HarbingerDawn | Date: Monday, 18.02.2013, 21:50 | Message # 60 |
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| Quote (Solaris) Nice video of Asteroid 2012 DA 14 featured on the APOD Great video!
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