A gravity tractor being used to alter the trajectory of an asteroid. Credit: NASA


The Menace of the Asteroids. Part 2: Defending Earth

By David Darling

A 500-meter-wide asteroid has just been discovered that will almost certainly collide with the Earth in 2030. No one knows yet where it will strike—on land or at sea—but its potential for regional devastation is high. The question is: what, if anything, can be done to stop it?

Fortunately, this shock announcement isn’t true: nothing is heading our way as far as we’re aware. But it’s very possible, given that only about a quarter of all the potentially hazardous asteroids out there have yet been detected, that some big dumb object has our name on it. So, having some form of planetary defense system in place makes a lot of sense.

Approaches to dealing with the threat of asteroid (or comet) impacts fall broadly into three categories that we can call the three D’s: duck, destroy, or deflect. “Duck” means we’d do our best to get out of the way of the impact zone by evacuating the area or, in the most extreme case of a planet-wide disaster, retreating to purpose-built underground shelters. Needless to say, this would be a last-ditch measure if other strategies had failed or not even been attempted.

Read more: The Menace of the Asteroids. Part 2: Defending Earth « AmericaSpace.

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