1. JFDee

    JFDee Senior Member

    Amazing how many people have cameras running nowadays ...

    Thanks to that fact, there are several excellent videos showing the entry and obvious breakup of a fairly big meteor (not "meteorite", please excuse the headline ...).
    Rumors are already flying, like UFO panic and bogus reports of a military intervention.

    There may have been incidents from pieces impacting the ground though.

    Anyway, the trail visible on the videos is stunning.

    http://www.youtube.com/watch?v=4ZxXYscmgRg

    https://www.youtube.com/watch?v=QIMKQihoYRI
  2. RolandD

    RolandD Active Member

    That was awesome!!!
  3. Cairenn

    Cairenn Senior Member

    And I expect that Alex Jones and the usual suspects will be full of conspiracy theories by morning
  4. Jazzy

    Jazzy Senior Member

    There was more than one piece in that. It's the largest I've ever seen. What are the odds of a Russian videoing from a car a meteor coming straight for him? I hope they find some piece of it.
  5. RolandD

    RolandD Active Member

    From my understanding, traffic conditions over there are so bad that everyone that can afford it has a dash cam installed so that they can have evidence in the event of an inevitable accident and be compensated.
  6. MikeC

    MikeC Senior Member

    It's not like you to spout hyperbole like that - neither of the videos linked show a meteorite coming "Straight at" the camera - both seem to show the path being away from the camera, albeit at an angle.

    And it looks like the odds of some video being taken were about 200%..so far! :)
  7. JFDee

    JFDee Senior Member

    There are now reports of injuries. A school and some other houses have been hit, according to Russian officials (via DPA).

    Edit: A factory building was also damaged.

    Annother edit: The damages were likely caused by the pressure shock of the main body explosion.
  8. Jazzy

    Jazzy Senior Member

    You misunderstand. I was suggesting the odds were most unlikely. But it would be an interesting sight, wouldn't it?

    Actually I seem to recall that people have been struck by meteorites. Probably apocryphal?
  9. Jazzy

    Jazzy Senior Member

    I thought at one point it became indistinguishable from a nuclear weapon. That was one bright flash.
  10. Jazzy

    Jazzy Senior Member

    I know. I'm a YT accident junkie, and Russian traffic features strongly. As do Finnish rallies...

    I've had five accidents in fifty years driving, and know that my failure to anticipate them was the cause. So I appreciate these things, and remember... :)

    The local youths leave the roads in droves as soon as it rains here in Tenerife. And it doesn't pay to leave the road here. You leave much less impression on a volcanic terrain than it does on you. I no longer enjoy driving for pleasure as much as I did in my youth. Hardly anything's the same.
  11. JFDee

    JFDee Senior Member

    The trail (most likely smoke) stayed visible for several minutes, so there should be a plethora of images available shortly for the "not-a-contrail" corner.

    Here is one from chelyabinsk.ru, by Yekaterina Pustynnikova:

    meteorite_trail.jpg
  12. Mick West

    Mick West Administrator Staff Member

  13. Mick West

    Mick West Administrator Staff Member

    I was just talking to someone about that:

    http://www.animalnewyork.com/2012/russian-dashcam/
  14. Mick West

    Mick West Administrator Staff Member

    All the injuries seem to be from broken glass from the shock wave.

    I wonder if there is a contrail component to the trail though. THere are plane contrails visible here:



    It does look more like smoke from the color though.
  15. JFDee

    JFDee Senior Member

    Well, why shouldn't the smoke particles be able to act as condensation nuclei?

    BTW, all the videos seem to have gone. I suspect the creators will try to sell them (not that they could be blamed) ...
  16. Mick West

    Mick West Administrator Staff Member

    I was thinking more like aerodynamic effects.

    I've put links to mirrors of the videos above.

    There's quite a lot of people trying to jump on the YouTube bandwagon meteor bandwagon, including some fakes:



    They use this natural gas fire crater:
    http://en.wikipedia.org/wiki/Derweze
  17. RolandD

    RolandD Active Member

    This event is excellent evidence of what occurred during the Tunguska event.
    • Like Like x 1
  18. Jay Reynolds

    Jay Reynolds Senior Member

    Russia Today has a report including a compilation of many videos:

  19. RolandD

    RolandD Active Member

    I would like to amend my first comment up there. The video is awesome, but the injuries and damage it caused is not. There are now hundreds of homes open to the elements due to broken windows.

    Jay, that video shows how reporters create misinformation. I noticed several scientific inaccuracies by the male reporter trying to look smart.
  20. Trailspotter

    Trailspotter Senior Member

  21. MikeC

    MikeC Senior Member

    Would they be too high in the atmosphere??
    Regarding driving conditions this was in a local paper today -

  22. Ross Marsden

    Ross Marsden Senior Member

    I am interested in the dual nature of the smoke(?) cloud that remains. A few observations then: The cloud just hangs there, so no or very little wind, and no or very little wind shear. And the twin-cloud look, side-by-side. Is that caused by the intense heat causing convection that effectively splits the cloud into two bits alongside each other?
    Thoughts?

    It shouldn't be too hard to place this thing in 3D space given all the photos available. I haven't acquired the knowledge/skill to do that.
  23. Rico

    Rico Active Member

    You asked, and so he delivered. Quoted from infowars.com:
    Don't have time to see what it's about yet but... "kinetic bombardment" gave me a few 'lol' moments.
  24. Billzilla

    Billzilla Senior Member

    I would guess that the main body of the meteor is starting to split up at that point. It might coincide with the bright flash seen in the videos.



    It definitely nothing to do with asteroid DA14 as it came in from the opposite direction.
  25. Mick West

    Mick West Administrator Staff Member

  26. captfitch

    captfitch Senior Member

    Has the altitude of that part of the cloud been determined? The clips with sound I have found don't have the actual explosion in them, just the trail and then the boom.
  27. Mick West

    Mick West Administrator Staff Member

    Interesting theory. I would intuitively think though if there was such an upwelling, then you'd get a trail with a cross-section like a mushroom.

    But it's obviously not a normal event, so maybe intuition is not the best guide. Perhaps, seeing as it's hyper-sonic, there's a distinct spatial separation between the trail of smoke that comes from the surface, and the trail of super heated air that extends out in front and below the rock to the shock wave. At the very least there is clean superheated air some distance in front of the rock.

    From what I've read of the space shuttle, in re-entry most of the heat comes from compression, not friction with the surface. See:

    http://en.wikipedia.org/wiki/Atmospheric_entry

    [​IMG]
    Last edited: Nov 20, 2013
  28. solrey

    solrey Senior Member

    Given the way it broke up it was probably some sort of Chondrite, which can contain significant amounts of water.

    According to the Wiki entry for the event, there were three different blasts.

    I wonder if one of the blasts was a sonic boom. It does look like it broke into two large pieces and those pieces shattered into smaller fragments. As it broke apart a significant amount of water and other volatiles would have been exposed for the first time in like 4 or 5 billion years. Cool.
  29. PCWilliams

    PCWilliams Senior Member


    meteor_300px.jpg
  30. RolandD

    RolandD Active Member

    From the videos I found that were taken while the shockwave reached the camera, there appears to be one extremely loud boom from the main explosion and several, 5 or 6 at least, subsequent booms which could be sonic booms or smaller explosions.
  31. TEEJ

    TEEJ Senior Member

    130215_mtsat_vis_meteor_trail_anim.gif

    http://cimss.ssec.wisc.edu/goes/blo...013/02/130215_mtsat_vis_meteor_trail_anim.gif


    http://cimss.ssec.wisc.edu/goes/blog/archives/category/general-interpretation


    'Meteor vapour trail animation, 15th Feb 2013'


    http://www.flickr.com/photos/simon_rp/8476482308/
    • Like Like x 1
  32. hemi

    hemi Senior Member

    One thing I haven't seen is a explanation of why the meteor exploded? Anyone?
  33. Mick West

    Mick West Administrator Staff Member

    I don't think it's an explosion in the traditional sense, more a very energetic disintegration spread over a long region. The shock wave that blew out windows was from the bow wave, sonic boom, not from an explosion.

    [​IMG]

    http://news.discovery.com/space/ast...alling-meteor-packed-a-sonic-punch-130215.htm

    Last edited: Nov 20, 2013
    • Like Like x 1
  34. GregMc

    GregMc Senior Member

    Yup, I think people are partly reacting to the sonic boom and being partly influenced by the misconception that a sonicboom is only heard just as an object "breaks" the sound barrier and is not heard at other times. Of course a supersonic object continuously produces a shockwave that is perceived as a sonic boom as the shockwaves pass over an observer.
    The object does create a huge flash and the disturbance of the atmosphere would also make a large noise separate to the sonic booms I think.

    The object does appear to get extremely heated as is plunges through the atmosphere then breaks apart in the larger fireball and the smaller parts of the disintegrating material are more greatly slowed by atmospheric drag and stay behind the rest in that glowing ember looking part of the trail that lingers momentarily.

    I'd guess that the heat of entry into the atmosphere greatly heats the object non-uniformly and the uneven thermal expansion would cause internal stresses to crack the surface material and front of the object and break it into smaller pieces.

    The smaller pieces would produce their own separate sonic booms which would reach a ground observer with slight delays and thus one would hear multiple booms once it breaks apart. The breaking apart no doubt would also produce some significant noise as the obvious heat and flash is producing atmospheric disturbance that would create a LOT of noise.
  35. RolandD

    RolandD Active Member

    Sorry, but it definitely exploded with a force of 500 kilotons of TNT, which is what caused the damage.

    From Wired:

    Why Does a Meteor Explode in the Air?

    more info from NASA:

    Russia Meteor Not Linked to Asteroid Flyby
    • Like Like x 1
  36. RolandD

    RolandD Active Member

    A quick follow-up, and this is just conjecture on my part. In an explosion of that magnitude, the shockwave will be traveling at hypersonic speeds, so the shockwave woulod reach the ground before the sonic boom.
  37. Mick West

    Mick West Administrator Staff Member

    The wired link paraphrases the data from NASA, which says:



    The key things there is "energy released". The only energy a space rock has is kinetic energy. Now I'd imagine there are variety of ways that can be translated into an "explosion", but what they are really talking about here with "500 kilotons of energy" is the energy needed to stop the rock, mostly from air resistence scrubbing off the speed . They are NOT quoting the energy of an explosion.

    You can verify this with the rough figures they gave:

    http://www.wolframalpha.com/input/?i=kinetic energy of 10000 tons at 18km/s
    kinetic energy of 10000 tons at 18km/s = 1.47*10^15 J

    http://www.wolframalpha.com/input/?i=energy of 500 kilotons of tnt
    energy of 500 kilotons of tnt = 2.1*10^15 J

    Approximately the same order of magnitude, essentially the same given the roughness of the estimates.

    Given the rock only weighed 10 kilotons, and it was not made of TNT, it was made of rock, you can see that all the energy must come from the motion of the rock.
    • Like Like x 1
  38. Mick West

    Mick West Administrator Staff Member

    That said, as soon as the rock begins to disintegrate, the air resistance rapidly increases, which would result in more disintegration, and more resistance possibly exponentially fast, which could have the characteristics of an explosion, depending on several variables.
  39. RolandD

    RolandD Active Member

  40. solrey

    solrey Senior Member

    Last edited by a moderator: Nov 20, 2013

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