Mitigation of Hazardous Comets and Asteroids

Gravitational interactions between planets and small bodies in the solar system can theoretically send asteroids and comets onto a collision course with Earth. This happens persistently in the fall of meteorites to Earth, though with masses that only rarely do any damage. The finding of craters on almost all solid bodies in the solar system when spacecraft image their surfaces brings home the fact that no planet is spared collisions. Asteroids larger than 50 m across collide with Earth, on average, once every 600 years.