back to article Forget Bruce Willis, Earth's atmosphere is our best defense against meteorites

Researchers have discovered why most meteorites disintegrate before they reach Earth - and it's all to do with atmospheric pressure. Previously it was thought that compression of air particles is what causes meteorites to wear away as they make their way down to our planet's surface, but many, like the 2013 Chelyabinsk …

  1. Anonymous Coward
    Mushroom

    So what happened to the 12,000 ton Chelyabinsk meteorite?

    If they only recovered 5 tons of it, where did the other 11,995 tons go? Certainly it did not convert to energy (Siberia would be leveled otherwise) and not all that mass was superheated and changed phase to gas. And I am sure that most of the fragments were not found and have become part Siberia now, but if scientists only found 5 tons, I have to think that a large majority of the meteorite did not land as solid fragments.

    I have to think that much of the meteorite was blown to dust by the explosion in the upper atmosphere, and has probably precipitated out worldwide by now.

    1. Dave 126 Silver badge

      Re: So what happened to the 12,000 ton Chelyabinsk meteorite?

      Maybe after finding five tonnes the scientists decided they had enough samples for their purposes, and went home!

      I image the larger chunks were easier to find and indentify as bit of meteorite. Gravel sized bits falling in a car park might be hard to spot, as would be larger bits that fell into rivers.

    2. User McUser
      Mushroom

      Re: So what happened to the 12,000 ton Chelyabinsk meteorite?

      If they only recovered 5 tons of it, where did the other 11,995 tons go? Certainly it did not convert to energy (Siberia would be leveled otherwise)

      I am not a physicist but I believe 11,995 tons converted into energy would not just destroy Siberia. Pretty sure it would destroy the entire planet several times over.

      A one megaton explosion equates to about 46.5g of material being converted into energy. So 11,995 tons works out to be roughly 234,014,644.222 Megatons.

      1. Anonymous Coward
        Anonymous Coward

        Re: So what happened to the 12,000 ton Chelyabinsk meteorite?

        If it is 20% air, it was probably formed as gravity from a few good size chunks (the 5 tons they found) attracted some gravel/sand size pieces and many tons of dust. The dust would just disperse in the atmosphere and probably ended up all over the planet - and some of may still be aloft.

        1. Neil Barnes Silver badge
          Coat

          Re: So what happened to the 12,000 ton Chelyabinsk meteorite?

          >> and some of may still be aloft.

          You'd think a loft floating around would be pretty easy to spot, though?

      2. Paul Hovnanian Silver badge
        Boffin

        Re: So what happened to the 12,000 ton Chelyabinsk meteorite?

        "11,995 tons converted into energy"

        I don't think so. Not E=mc^2 anyway. More like the kinetic energy of 12,000 tons moving at about 20 km/sec. About 2.4E15 Joules. Or around 523 kiloton TNT equivalent. Big, but it 'burst' at 30 km altitude. And it lost some of that energy over a significant distance. Not in the milliseconds of a single blast.

        That breakup resulted in something like 11,995 tons of dust and little stuff that we will never find plus 5 tons of stuff big enough to identify.

    3. Field Commander A9

      Re: So what happened to the 12,000 ton Chelyabinsk meteorite?

      Burnt up / vaporized in high atmosphere.

      1. Anonymous Coward
        Anonymous Coward

        Re: So what happened to the 12,000 ton Chelyabinsk meteorite?

        "If they only recovered 5 tons, where did the other 11,995 tons go? "

        Um ... could some appreciable fraction of it have been ice ?

    4. Lars Silver badge
      Happy

      Re: So what happened to the 12,000 ton Chelyabinsk meteorite?

      Who cares. A few kilos is enough for scientific use. People collect stuff like that as souvenirs, just put a price on it and more will turn up. Some will be found on Ebay too.

      1. handleoclast
        Coat

        Re: So what happened to the 12,000 ton Chelyabinsk meteorite?

        People collect stuff like that as souvenirs, just put a price on it and more will turn up. Some will be found on Ebay too.

        Pretty much the same thing happened in mediæval times with fragments of the true cross and the nails from the crucifiction. Apart from eBay, of course. They only had Amazon back then.

      2. Stratman

        Re: So what happened to the 12,000 ton Chelyabinsk meteorite?

        Some will be found on Ebay too.

        About 20,000 tons of it, if Ebay runs true to form.

    5. phuzz Silver badge

      Re: So what happened to the 12,000 ton Chelyabinsk meteorite?

      You can actually collect some of the dust for yourself, from your guttering.

      Just scrape out some of the mud you find there, and sort it with a magnet. They examine it under a microscope and you have a good chance of finding some tiny fragments.

      1. Lars Silver badge
        Coat

        Re: So what happened to the 12,000 ton Chelyabinsk meteorite?

        @phuzz, so true.

        From the article:

        "It’s the first time the dust has been found in urban dirt. Previously, the frozen wastes of Antarctica were the usual collection sites."

        But to be more precise it's apparently the first time they have tried to look in urban dirt and the reason they collect in Antarctica is that it's so much easier to spot bigger pieces against the ice or snow.

    6. This post has been deleted by its author

    7. MyffyW Silver badge

      Re: So what happened to the 12,000 ton Chelyabinsk meteorite?

      Must object to phrase in article that said "destroyed a lot more matter" - as others have noted it cannot have been destroyed (or converted to energy) or we'd all be lots of little pebbles orbiting in the goldilocks zone.

    8. Anonymous Coward
      Anonymous Coward

      Re: So what happened to the 12,000 ton Chelyabinsk meteorite?

      It went thorough a stargate, maybe(?)

  2. Anonymous Coward
    Anonymous Coward

    How is John McClain going to stop a meteorite? European ones maybe.

    1. This post has been deleted by its author

      1. Anonymous Coward
        Anonymous Coward

        Easy mistake, I always get connor mccloud mixed up as well, he's the last cloud provider.

  3. veti Silver badge

    Doesn't follow

    You can't tell me that shooting Bruce Willis at the offending object, with sufficient force, wouldn't also help to break it up. So we want to keep him in reserve all the same.

    1. Fading
      Mushroom

      Re: Doesn't follow

      I am with you on this one - there hasn't been enough research done on a Willis cannon for defense against meteorites. Given the average density of Hollywood stars some simple back of the beer mat F=MA calculations and we could have a working prototype within weeks. Now where did all those bits for Saddam's Babylon project end up?

    2. My Alter Ego

      Re: Doesn't follow

      Regardless of whether it'd make a difference, surely it'd be worth trying. Every little helps...

  4. Mark 85
    Coat

    Armageddon or Armageddon It On"? I get those two movies confused...

    I got my coat, I'll go quietly. The coat is one in the last row...

  5. Field Commander A9

    Just goes to show how clueless some film makers are.

    Looking at you, "Your Name."

  6. Anonymous Coward
    Anonymous Coward

    "the explosion when it was above the surface may have destroyed a lot more matter"

    I find this rather grating in something posted under the "Science" banner. Might I suggest "dispersed" instead of "destroyed"?

  7. disgruntled yank

    "Forget Bruce Willis"

    I had done a pretty good job, until you wiseacres came up with the headline.

  8. the Jim bloke
    Go

    This has changed my understanding of the universe.

    Not the irrelevant trivia about air pressure blowing meteors apart, but the realization that in the absence of planetary rock-forming factors - heat, pressure, a cementing medium, or solidification and crystallization from a molten fluid - space rocks are not giant flying hammers of global extinction, but just a bunch of particles hanging around together for lack of anything better to do...

    wow.

    or

    Its rocks Jim, but not as we know it.

POST COMMENT House rules

Not a member of The Register? Create a new account here.

  • Enter your comment

  • Add an icon

Anonymous cowards cannot choose their icon

Other stories you might like