Tuesday, January 06, 2009

History: The Universe: Stopping Armageddon: asteroids

Tonight, Jan. 6, The History Channel held the first of its "The Universe" “Stopping Armageddon” programs, this one focused on how to stop an asteroid.

A ten mile asteroid would create a 100 mile crater and extinguish human life. Such an asteroid can hit perhaps every 500 million years. An asteroid the size of a few hundred meters exploded over Siberia in 1908 (Tunguska) and would destroy a city. It probably occurs every 500 years. The program discussed the possible impact of Apophis in 2029 or 2036 (NASA link), and the “keyhole” effect that could increase the probability of a hit in 2036.

Many technologies may be possible to prevent an asteroid hit. The best chance is to deflect it, and the farther away it is when hit by a deflecting object, the better, because the less it has to be deflected. It is not a good idea to blow a large asteroid up into pieces, several of which could still do severe damage when falling to Earth. The European Space Agency has on the drawing board a “Don Quixote” kinetic impaction device. Another concept is the “gravity tractor” and a far out design would be laser deflection.

We are likely to find even more near-Earth objects. Jupiter probably saves us from many impacts, and a large asteroid may have hit Mars a couple billion years ago, destroying most of its atmosphere and magnetic field, resulting in the desert planet today.

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