How often do asteroids strike Earth?
While this asteroid is very unlikely to hit the Earth, it is certain that one will do so at some point in the future. Asteroids up to 100 metres across strike approximately once every 50 to 1,000 years, and can cause severe local devastation – as is thought to have happened at Tunguska in Siberia in 1908. Larger objects, capable of causing regional devastation, strike every 1,000 to 100,000 years, and ones more than a mile across, which can cause “nuclear winter” effects, hit still less frequently. Can anything be done to stop a strike? Scientists believe that, given sufficient warning of an impending impact, it should be possible to divert an asteroid’s path to take it away from Earth. One approach would be to explode a nuclear bomb on or close to the asteroid, as in the film Armageddon, to nudge it into a more favourable orbit. This, however, is a high-risk strategy that could itself cause disaster: there is a strong possibility that the explosion would blast the asteroid into thousa
