Scientists think that the asteroid which is believed to have wiped out the dinosaurs 65 million years ago was related to a present-day asteroid in the main asteroid belt between Mars and Jupiter. Computer simulations show that this asteroid, called 298 Baptistina, collided with another body 60 million years ago and then shattered into thousands of pieces, some of which pummelled the inner planets of the Solar System.  Scientists believe that there is a greater than 90 per cent chance that one of these pieces became the asteroid that created the Chixulub crater in Mexico, which formed 65 million years ago and released millions of times more energy than a nuclear bomb.

Willima Bottke and this team at the Southwest Research Institute in Colorado ran several computer simulations to determine how the orbits of 298 Baptistina, and other asteroids with similar orbits and compositions, had evolved.  The results suggested that all of these asteroids came from a single parent asteroid which collided with another body and then shattered into about one thousand bodies larger than on kilometre wide, as well as many smaller fragments. Around twenty per cent of these left the asteroid belt, and about two per cent of those collided with the Earth.

Measures of crater ages on the Earth and Moon show unusually high impact rates roughly 100 million years ago, which fit with the results shown by the simulations.