NUCLEAR OPTION

If gentler measures fail, nukes are still an option for warding off an incoming asteroid. But not in the blow-itup manner depicted in the 1998 movie Armageddon. Instead, a bomb (or bombs) could be detonated close to the asteroid, and energy from the blast would superheat the near side of its surface, vaporising it and causing material to blow off into space. The effect would be to turn that side of the asteroid into a rocket nozzle powerful enough to divert its course.

This might be the best response if the Earth finds itself threatened by a fast-moving, incoming comet, like the one in the 2021 movie Don’t Look

Up, where there’s not a lot of time to react. But for the type of near-earth asteroid most likely to be dangerous, like the 800m object that passed by the Earth on 18 January (about the size of the Empire State Building), it’s probably not necessary to resort to nukes – given that they’d be, at the least, highly controversial.