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Saturday, February 5, 2011

Avoiding an asteroid collision

65 million years ago, a colliding asteroid had a devastating effect on Earth’s ecosystems. How can we prevent this from occurring again? According to a paper presented at the 73rd Annual Meeting of the International Meteoritical Society by Gregory Matloff of New York City College of Technology, the best choice may be to try to deflect incoming asteroids rather than destroy them.

This could be accomplished by heating the surface of the asteroid just enough to create a jet stream, which would in turn alter the object's trajectory, hopefully away from the Earth. And just how do you heat up an asteroid? One way would be to construct a solar collector that could travel alongside the asteroid, concentrating the sun’s energy onto that asteroid. If the solar collector were sent out early enough, the heating could take place gradually over many months or even years, slowly nudging the asteroid out of Earth’s path.

There are a few problems with this approach, not least of which is that such a device has never been built, let alone tested. It’s not clear whether we would be able to launch such a device with the precision required to generate the exact amount of heating needed to steer an asteroid away from the Earth. Still experiments are underway. Matloff and his team have been testing red and green lasers against asteroid samples here on Earth to see how far the beams penetrate and how much they heat up the rocks.

Asteroid collision is not an ideal threat by the way. Some day, another giant asteroid will cross Earth’s path. That day may come as early as 2036 if the asteroid Apophis passes through a specific ‘keyhole’ of space as it approaches us (impact estimated at a one in 250,000 chance, so don't sell all your possessions yet). Russian and American teams already disagree about how to treat this unlikely disaster. NASA hopes to have a contingency plan ready with plenty of time to spare.

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