The fate of the dinosaurs was sealed almost 100 million years before they were wiped out and before many of the latest species had even evolved, according to research that reveals how a cosmic collision caused mass extinction on Earth.

The 10km-wide (6.2 miles) asteroid that crashed into the Yucatan peninsula of Mexico 65 million years ago, causing the end of the dinosaurs, was almost certainly created by a head-on smash between two even-larger space rocks about 160 million years ago, scientists have discovered.

An asteroid 170km (105 miles) in diameter was ripped into thousands of smaller fragments, known as the Baptistina family, when it was struck by another, 60km wide, at a speed of 3km per second.

It peppered the Earth, the Moon, Venus and Mars with debris that has scarred their surfaces to this day, a study led by William Bottke, of the Southwest Research Institute in Boulder, Colorado, has found.

One of the larger pieces spiralled through space for 95 million years before striking the Earth 65 million years ago, forming the Chicxulub crater and triggering the Cretaceous/tertiary mass extinction event in which the dinosaurs died out.

The Baptistina asteroid shower continues to threaten the Earth. It produced at least 1,000 smaller asteroids at least 1km in diameter, and between a fifth and a third of the near-Earth objects that cross our planet’s orbit. A strike from a 1km object would cause devastation on a continental stage and threaten the survival of civilisation, while another 10km impact would have the same effect it did 65 million years ago.

Such an event remains very unlikely. Though the Baptistina break-up is thought to have doubled the rate at which large asteroids strike the Earth, only one 10km object collides with the planet every 350 million years.

The study, which is published in the journal Nature, sought to explain why the cratering rate on the Earth and the Moon appears to have doubled over the past 100-200 million years.

Dr Bottke’s team traced the increase to an event 160 million years ago, in which the asteroid family was born. It takes its name from the largest member that still exists today, a 40km asteroid known as Baptistina.

Dr Bottke said chemical analysis showed that the asteroid shower was the most likely source, a 90 per cent probability, of the impact that produced the mass extinction of dinosaurs 65 million years ago. The other possibilities - that it was a comet from the edges of the solar system, or a preexisting asteroid - had only a 10 per cent chance of being correct.

Philippe Claeys, of the Free University of Brussels, Belgium, said that the most important point raised by Dr Bottke’s work was how severe the repercussions of cataclysmic collisions in the asteroid belt could be for the Earth-Moon system: “The terrestrial impact record needs to be scrutinised more closely to identify and understand these periods of more intense bombardment, and to link them to the huge and dangerous game of billiards continuously being played out between the orbits of Mars and Jupiter.”

Explore World News

• World Agenda

• Iraq News

• US & Americas News

• Europe News

• Middle East News

• Afghanistan News

• Asia News

• Africa News

• Ireland News

Times Recommends

• It’s only Brits who don’t appreciate me, says Blair
• Party’s over for Greek graspers
• White House tightens security for Xmas marathon