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Thread: Meteorite Hits Russia

  1. #21

    Default Re: Meteorite Hits Russia

    It seems that the meterorite managed to locate a politically sensitive region of Russia - home to quite a bit of nuclear energy industry.
    Hwang Xian Sheng
    Kaohsiung/Gaoxiung
    Taiwan/Formosa
    R.O.C/Province of China, P.R.C.

    "My comments are independent... and at times just plain wrong. At other times, they just might be helpful. So consider the source."

  2. #22

    Default Re: Meteorite Hits Russia

    Quote Originally Posted by Heater. View Post
    Of course space being so big and us being so small has it's benefits. It means there is a lot less chance of this stuff actually hitting us.
    Technically that's true, but the reality is just considering the asteroid belt and the ORT cloud, any chunk of rock could break orbit and take on a path to hit the Earth without any prediction of the event. Coupled to this fact, the Solar System is also traveling through space and can attract and capture rogue asteroids which can also impact the Earth. The large number of big rocks that have passed the Earth in the past several decades, at near miss distances (roughly Earth-Moon distance, more or less) should be a wake-up call for the human race.

  3. #23

    Default Re: Meteorite Hits Russia

    The near-miss asteroid that passed by Friday was expected to fly lower than many of the artificial satellites in orbit. But the experts said it was just going to be a miss.

    So we have a bit of drama. This is certainly far less that moon-earth distances.

    I hope I haven't worried youall. Get in touch with your 'inner Chicken Little'.

    http://www.bbc.co.uk/news/science-environment-21442863
    Hwang Xian Sheng
    Kaohsiung/Gaoxiung
    Taiwan/Formosa
    R.O.C/Province of China, P.R.C.

    "My comments are independent... and at times just plain wrong. At other times, they just might be helpful. So consider the source."

  4. #24

    Default Re: Meteorit Hits Russia

    Quote Originally Posted by Duane C. Johnson View Post
    I have meen trying to determine if the Chelyabinsk, Russia meteorite was related to the DA14 asteroid.
    Apparently its not....
    I've often wondered about this sort of thing: what if one of a group of small asteroids hits the moon and knocks some cheese into earth's orbit? Is it possible for the cheese to come down in a trajectory different from the parent group? Or is this possibility full of holes?

  5. #25

    Default Re: Meteorit Hits Russia

    Hi Aye;
    Quote Originally Posted by ElectricAye View Post
    I've often wondered about this sort of thing: what if one of a group of small asteroids hits the moon and knocks some cheese into earth's orbit? Is it possible for the cheese to come down in a trajectory different from the parent group? Or is this possibility full of holes?
    That's a bit of a different question.
    If the Russian rock broke of DA12 its new orbit would be very similar to the parent.

    Now if it were truly blasted off, probably eons ago, the new orbit could be quite different. However, the several objects can be tracked back to the common point where the collision occurred. There are a number of asteroid families such as the Baptistina group. These all have similar orbit inclinations and momentums since they were most likely from a big collision long ago.

    The longer time passes these families get more dispersed until they get unrecognizable.

    Duane J

  6. #26

    Default Re: Meteorit Hits Russia

    Here we are with a long anticipate 45 meter meterorite arriving on schedule, and out of the blue comes a 15 meter meterorite that scares the daylights out of us.

    I wonder why we missed the 15 meter one that really did hit earth. Good or bad criteria?
    Hwang Xian Sheng
    Kaohsiung/Gaoxiung
    Taiwan/Formosa
    R.O.C/Province of China, P.R.C.

    "My comments are independent... and at times just plain wrong. At other times, they just might be helpful. So consider the source."

  7. #27

    Default Re: Meteorit Hits Russia

    Quote Originally Posted by Duane C. Johnson View Post

    The longer time passes these families get more dispersed until they get unrecognizable.

    Duane J
    My family is just like that.
    "Give a man an inch, and right away he thinks he's a ruler." Maxwell Smart

  8. #28

    Default Re: Meteorit Hits Russia

    Hi Loopy;
    Quote Originally Posted by Loopy Byteloose View Post
    Here we are with a long anticipate 45 meter meteorite arriving on schedule, and out of the blue comes a 15 meter meteorite that scares the daylights out of us.

    I wonder why we missed the 15 meter one that really did hit earth. Good or bad criteria?
    DA12 was barely detected last year only because it passed by so closely.
    A 10m or 15m object is probably under the detection limit even if it did pass close by.
    And certainly not when far away.

    Duane J

  9. #29

    Default Re: Meteorit Hits Russia

    Quote Originally Posted by ElectricAye View Post
    I've often wondered about this sort of thing: what if one of a group of small asteroids hits the moon and knocks some cheese into earth's orbit? Is it possible for the cheese to come down in a trajectory different from the parent group? Or is this possibility full of holes?
    Yes, In the case of stuff from Mars, exactly that happened, and the stuff was blasted out of Mars orbit and found its way onto the earth in the form of meteorites. It also led to the life controversy when small fossils were found in the rock.

  10. #30

    Default Re: Meteorit Hits Russia

    Quote Originally Posted by Loopy Byteloose View Post
    I wonder why we missed the 15 meter one that really did hit earth. Good or bad criteria?
    We have no system in place to track every 15-meter sized object in space.

  11. #31

    Default Re: Meteorit Hits Russia

    Quote Originally Posted by Tor View Post
    It appears to have been around 15 meters diameter (one Nasa source estimated 15-17m), another source says it may have been an iron meteorite (not confirmed), and a third source estimated it to be 10 tonnes (relayed via BBC but unconfirmed).
    Anyway the explosion was several kilotons. Largest hit since Tunguska 1908. And arriving from the direction of the sun, very difficult to spot.
    Its not clear there was any definite explosion at all from the footage I've seen, the damage is consistent with a sonic boom IMO - remember these things literally
    cut a hole through the atmosphere at hypersonic speeds (Mach 44 initially!) and melt/ablate into a trail of super-hot plasma. A detonation would have
    stopped it dead(*) with a big flash (a soft comet would be more likely to do this than a hard iron meterite). The footage shows it flaring up and brightening
    a lot, but over several seconds, then fading back down to a much less bright blob still travelling fast - presumably large amounts of it were vaporising
    and creating an intense fireball but not really an "airburst" - perhaps it shed lots of pieces that each burnt up and the largest piece carried on?

    Since the boom and messy disintegration spreads the energy along a trail the local damage was probably a lot less than a single detonation of the same energy.
    This is much smaller than the Tunguska one which was comparable to an H-bomb and estimated as 100m diameter (200 times the volume). I wouldn't want to
    be near one any bigger than this recent one though

    And yes a 15m object coming towards you at Mach 44 is incredibly hard to spot even minutes before it arrives! But the 15m objects don't pose such a great
    risk - the asteroid that missed earth the same day is the sort of thing to worry about.

    (*) relatively speaking

  12. #32

    Default Re: Meteorit Hits Russia

    The last reports (from the Russian Academy of Sciences) suggest that it disintegrated (with the power of a small nuke, so 'explode' would be an alternative description) 30-50km up in the atmosphere.

  13. #33

    Default Re: Meteorit Hits Russia

    Quote Originally Posted by Tor View Post
    The last reports (from the Russian Academy of Sciences) suggest that it disintegrated (with the power of a small nuke, so 'explode' would be an alternative description) 30-50km up in the atmosphere.
    Thank goodness it wasn't misinterpreted as something other than a meteor .....

  14. #34

    Default Re: Meteorite Hits Russia

    For the record the Russian meteor is not related to the asteroid near miss, just a coincidence. Parts of it are in a frozen lake and presumably will be recovered and
    analyzed in due course. I've also heard 10 tonnes (which isn't anything like 17m diameter), but that might mean a fragment on the ground, not the original size.

  15. #35

    Default Re: Meteorite Hits Russia

    Quote Originally Posted by Mark_T View Post
    For the record the Russian meteor is not related to the asteroid near miss, just a coincidence. Parts of it are in a frozen lake and presumably will be recovered and
    analyzed in due course. I've also heard 10 tonnes (which isn't anything like 17m diameter), but that might mean a fragment on the ground, not the original size.
    The suggested weight has been estimated loosely at 500 tons.

    Duane J

  16. #36

    Default Re: Meteorite Hits Russia

    I was just now reading BBC, and according to the BBC Nasa estimates the pre-entry weight to 10,000 tonnes. And releasing 500 kilotons of energy.

  17. #37

    Default Re: Meteorite Hits Russia

    The problem isn't that we aren't "tracking" such small asteroids, it's that we can't see them at all except when they're extremely close to earth. The detection limit is only roughly set by the size of the asteroid. The position relative to the earth and sun and instrument sensitivity are the biggest factors; even large asteroids are faint when far away. WRT tracking, only when there are relatively close encounters between an asteroid and a larger body does the orbit change appreciably, in most cases once the orbit is known the asteroid can always be found so there's no need to track it per se. For that reason asteroids also don't really leave the asteroid belt except in the rarest circumstances. The asteroids and planets have been doing their little orbital dance for eons and so the asteroid belt as it exists is what's left after all the unstable orbits have been swept clear. Nearly all the opportunities for a planet like Jupiter to perturb asteroid orbits significantly have already happened many times. That said, there are still a lot of asteroids around whose orbits were disrupted some time in the past such that they became earth-crossers or one of the other families already mentioned. Most asteroids in oddball orbits are vicitms of some past gravitational encounter with Jupiter. They just haven't hit anything. Yet.

    The instruments used for detecting asteroids can only see so faint. The detectors are pretty good already, with very high quantum efficiency so there aren't a lot of photons going to waste. To go fainter, you need bigger telescopes. But bigger scopes tend to have longer focal lengths, which means the field of view gets smaller so you cover less sky in any one image. That means you need more of them to get adequate coverage. In the grand scheme of things, the rock that hit Russia was very unusual. It was very large (compared to most that hit the earth), it hit land when 3/4 of the planet is water, and it hit a fairly densely populated area when most of the land is wilderness. Even then, the damage was relatively minor, and I think given the odds of it happening that you'll have a hard time convincing any government to cut loose too much more money for asteroid searches. The silver lining of this cloud is that this might stop governments from cutting funding for asteroid searches as there have been many calls to do.

    Even if we go to larger scopes, such small asteroids will still only be visible when they're relatively close to earth. It isn't practical to get orders of magnitude gains in sensitivity. There are new telescopes being put into service that will increase the number of objects we can find: http://pan-starrs.ifa.hawaii.edu/public/ but trying to get every rock down to a few meters probably won't happen.
    Last edited by jones; 02-17-2013 at 08:25 PM. Reason: added info about pan-STARRS

  18. #38

    Default Re: Meteorite Hits Russia

    This is being blamed on the russian meteorite

    http://www.thisissomerset.co.uk/Gree...#axzz2LI4VykPT

  19. #39

    Default Re: Meteorite Hits Russia

    Quote Originally Posted by skylight View Post
    This is being blamed on the russian meteorite

    http://www.thisissomerset.co.uk/Gree...#axzz2LI4VykPT
    I've seen this somewhere before......Click image for larger version

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Views:	56
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ID:	99349

  20. #40

    Default Re: Meteorite Hits Russia

    Quote Originally Posted by pmrobert View Post
    I've seen this somewhere before......Attachment 99349
    I saw that movie as a child on TV on a Saturday afternoon in 1970. I don't think I slept well that night.

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