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When a meteoroid enters the atmosphere

  1. May 24, 2010 #1
    When a meteoroid enters the atmosphere and becomes a meteor, it burns due to great fraction between the rock and and the air. But how scientists calculate the exact amount of kinetic energy converted to heat due to fricton and how much of this is used to heat up the rock and how much of it is used to heat up the air surronds it? Can they quantitatively analyze each part of its journey until it hits the ground?
     
  2. jcsd
  3. May 24, 2010 #2
    I'm not entirely sure about this, but I suspect that the problem is analysed numerically (using a computer/supercomputer), using the Navier-Stokes equations. The problem is really very complex, and involves both frictional effects (stokes drag) and the creation of a turbulent wake behind the meteoroid, which leads to a stark pressure difference which slows the meteoroid down. This is just a guess though, I'm not in the business of atmospheric meteoroid modelling. It's also possible that they analyse historical meteoroid data to watch for trends and thus build up empirical models.
     
  4. May 24, 2010 #3

    rcgldr

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    Most of the heat is due to a very high amount of compression of the air, not friction. The amount of heat generated is very large, and the temperature of the object's surfaces becomes very high before it the heat output through radiation and convection via the air balance out the heat input, usually high enough to burn up the meteor.
     
  5. May 24, 2010 #4
    Be aware that the chance of a meteorite penetrating Earth's atmosphere to a "ground event" has a great deal to do with it's chemical composition.
     
  6. May 29, 2010 #5
    You are correct. The two general classifications are "dirty snowballs" and "metallic".
    Dirty snowballs usually explode high in the atmosphere, often refered to as a bolide event.
    Metallic objects have to be a certain size to penetrate the atmosphere and hit the ground.
    Near Odessa, TX, several years ago, an object hit the ground near a little league ball game. The boys who picked it up told the reporter that it was very hot when they picked it up but that within a few minutes is was very cold. This makes sense when you realize how cold space is and how little time friction had to heat up the object.
     
    Last edited: May 29, 2010
  7. May 29, 2010 #6
    Rapid compression of air can generate such levels of heat that Indonesions have used two bamboo tubes forming a piston chamber combination with a little tinder in the chamber to ignite fires. When the piston is forced down into the chamber the tinder ignites.
     
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