THE POTENTIAL cost to earth and civilisation from collision with asteroids is at least ten times greater than the hazard presented by the nuclear industry, scientists claim.
This week they will tell two Cambridge conferences that more research into possible cosmic disasters past and future is needed if we are to understand and possibly reduce the threat to Earth.
Professor Mark Bailey, director of the Armagh Observatory in Northern Ireland, will tell the conferences that latest research shows that Earth is liable to collide with space objects 1km in diameter once every 100,000 to 200,000 years.
Such a collision, he suggests, could wipe out between a fifth and a quarter of the world's population.
"We don't know when the next one is coming because we have not discovered the whole population of near earth objects yet," he said. "But we could if we put our minds to it. We will argue that this is a hazard in the same ball park as risks which are normally covered by government agencies such as the nuclear industry. There is a need to understand and to be able to predict when the next one is coming."
He added: "It is quite a horrifying prospect if we don't have warning. But there are various things which could be done if we knew ahead that one was on its way." American scientists are looking at ways of interception such as firing missiles into an object's orbit to destroy it.
Astronomers, anthropologists, historians and geologists will meet for the second conference to throw new light on past catastrophes.
According to Benny Peiser, an anthropologist from John Moores University in Liverpool, there is ice core and tree ring evidence of two or three major global environmental events during the Bronze Age. Among suggestions is that meteorites or comets smashing into the Earth may have caused the necessary devastation and change in climate to force the collapse of civilisations such as that of Mesopotamia.
Among the evidence to be presented at the conference is microscopic samples of soils and sediments from the Middle East, thought to date from 2,200bc and which contain calcite material only found in meteorites.