Russian scientists have proposed that the detonation of a nuclear weapon close to an asteroid may deflect the asteroid to a few degrees – that it may miss Earth . That is, if the action was carried several years prior to hitting.
The Russian and European idea was put forward up as part of the joint NEOShield project, whos task was to see how possibly dangerous objects could be stopped.
Further details would be required but have not been released. It should also be noted that launching and detonating nuclear weapons into the cosmos is at the moment banned.
At the moment we are unaware of any asteroids that are on a collision course with the Earth, so this study was carried out for purely hypothetical reasons. But there are a great many asteroids aren’t being tracked.
The likelihood of an asteroid hitting the Earth equivalent to the asteroid that was resonsible for the destruction of the dinosaurs are small, however many consider this to be an inevitably within the proceeding few thousand years. Therefore, having defense measures ready could be crucial if humans are to survive, and Bruce Willis isn’t around any more.