Wednesday, August 13, 2008

Most Meteorites Come from Asteroid Belt, Not from N.E.O.s

Contrary to what would be expected, MIT researchers have discovered that most meteorites do not originate as Near Earth Objects (N.E.O.s) but "fast track" from the asteroid belt.

Puzzled by a discrepancy between the type of meteorites that typically strike the Earth ("
stony objects, rich in the mineral olivine and poor in iron") and the type of asteroids that form the majority of N.E.O.s, researchers discovered that most meteorites had to be from the inner Asteroid Belt.

They found that most of these objects were gradually disturbed by the Yarkovsky effect, which is the slight effect caused by the sun heating part of the asteroid which then radiates the heat as it rotates, causing a slight wobble in the asteroid's orbit. This can sometimes cause an asteroid to be ejected from the Asteroid Belt and into the Earth's path.

This study is good news for protecting the Earth from impact as it adds to our understanding of what type of asteroid is likely to impact and therefore what methods might be most effective in dealing with a threat.

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