What can you do when asteroids are about to hit the Earth, and Bruce Willis is nowhere to be found? Apparently, the answer may involve nuclear explosions in space to try and speed it up.
The unusual suggestion comes from David Dearborn, from the Lawrence Livermore National Laboratory in California. He modelled a virtual asteroid as part of an investigation into how best to dodge a gigantic meteor-like bullet... and then added a nuclear blast, just to see what would happen, according to New Scientist:
Thirty years before the asteroid was set to collide with Earth, a nuclear blast, equivalent to 100 kilotonnes of TNT, was set off 250 metres behind it. The nudge from the explosion increased its velocity by 6.5 millimetres per second, a slight change but enough for it to miss us.
The technique also reduced the risk of a break-up - just 1 per cent of the asteroid's material was dislodged by the blast, and of that only about 1 part in a million remained on a collision course with Earth. Dearborn adds that the technology for this method is already established, unlike for the use of a heavy object to shove the asteroid onto a different path - the "kinetic impactor" strategy. "Should an emergency arise, we should know that [the technology] is available, and we should have some idea of how to properly use it," he says.
Dearborn's research also suggested that just blowing the whole asteroid up was also an option, although Derek Richardson of the University of Maryland in College Park disagrees for the best reason - You can't be sure that you're definitely going to be able to destroy the asteroid:
It may be that you just blow out a big hole on the surface.
After all, the last thing you want is to piss off the thing that's about to destroy you.
How to save the world from an asteroid impact [New Scientist]