Asteroids, and possible ways of keeping them away from Earth

Wednesday, 27 February, 2013

Earth has been menaced by a couple of asteroids and meteorites of late. Hopefully we’ve seen the last of these threats for a while, but it raises the question of how to deal with such objects, especially if there is some sort of advance warning that they are on the way.

Thankfully there are a couple of options on the table. Scientists in California for instance say it is possible to use laser beams to evaporate asteroids, or failing that, move them into less threatening orbits:

Described as a “directed energy orbital defense system,” DE-STAR is designed to harness some of the power of the sun and convert it into a massive phased array of laser beams that can destroy, or evaporate, asteroids posing a potential threat to Earth. It is equally capable of changing an asteroid’s orbit – deflecting it away from Earth, or into the Sun – and may also prove to be a valuable tool for assessing an asteroid’s composition, enabling lucrative, rare-element mining. And it’s entirely based on current essential technology.

Meanwhile, Sung Wook Paek, a MIT graduate, says splattering white paint on the surface of asteroids would also help alter their course:

Paintballs themselves could impart a slight momentum change to the asteroid, diverting it only slightly, but not enough to avoid Earth. The main effect would come from the paint’s increase in reflectivity on the asteroid. Thus, the pressure of photons coming from the sun, acting over enough time, could result in a large shift in course. Paek concluded that the course of asteroid Apophis, a 27-gigaton rock that is expected to pass close to Earth in 2029 and in 2036, could be changed enough to miss Earth. He estimated that 5 tons of paint would be sufficient to cover the 1,480-foot-diameter asteroid.

And just for the record, a map of the globe marking known meteorite strikes over the last four thousand three hundred years… there’s quite a few.

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