A computer simulation developed by scientists in Britain and Russia shows that asteroids with a diameter of 200 metres will hit the Earth's surface once every 160,000 years, instead of every 2500 years.

 

Bland and Natalia Artemieva of the Russian Academy of Sciences used the computer simulation and existing data on impacts to reach their estimates which are reported in the science journal “Nature”.

   

"Fewer asteroids (than expected) will make it to the surface of the Earth," said Dr Phil Bland, of Imperial College in London.

 

Impact

   

If a massive near-Earth object measuring more than a kilometre in diameter slammed into the planet it would cause global devastation and kill an estimated quarter of the world's population.

   

But scientists believe an event of that size would only occur about every 700,000 years.

   

Hollywood films such as "Deep Impact" and "Armageddon" raised public awareness of the threat of near-Earth objects and prompted calls for early warning systems.

   

A collision with the Earth 65 million years ago is thought to have wiped out the dinosaurs by changing the global climate. A smaller asteroid is credited with levelling 1000 sq km of the Siberian forests in 1908.