Asteroids 'threaten' Earth

The threat from space is not science fiction

By BBC News Online science editor Dr David Whitehouse

Experts are to tell the UK Government that more must be done to defend the Earth from the threat of rocks crashing on to the planet from outer space.

A task force established to assess the threat of the Earth being struck by so-called Near Earth Objects (Neo's) will say that the threat from space is not science fiction but something that should be taken seriously.

Its report, being released on Monday, has been written by Dr Harry Atkinson, who has worked for several space agencies and government research councils, Sir Crispin Tickell, the former British ambassador to the UN, and Professor David Williams, of University College London.

The publication of their report will coincide with asteroid 2000 RD53 passing the Earth at a distance that is just 12 times further away than the Moon.

The space rock is estimated to be 300-400 metres (980-1,300 ft) across and, although there is no danger of a collision with the Earth, it will highlight the task force's conclusions.

Hiroshima detonations

Astronomers calculated recently that there are nearly 1,000 asteroids that cross the Earth's path which are at least a kilometre wide.

A 100-metre-wide object crashes on to Earth every 10,000 years

The dinosaurs were probably wiped out by the impact of a 10-km (7-mile) wide object that struck the Earth 65 million years ago.

No-one has ever been killed, or even injured, by an asteroid (although there are some suggestions of a deadly medieval Chinese impact), but the consequences of being struck by a rock from space could be extremely serious.

It is estimated that a 100-metre wide object crashes on to our planet every 10,000 years with the force of a 100-megaton bomb.

Every 100,000 years, a one-kilometre-wide object strikes the Earth with the force of 10 million Hiroshima detonations.

International effort

The task force publishing its report was established in January by the government's science minister, Lord Sainsbury, with a brief to assess the danger from asteroids, what could be done to prevent impacts and how the dangers should be communicated to the public.

The report will make 14 recommendations. These include a plea that Britain should:

• >take a leading role in a greater international effort;
• improve its ability to detect any incoming objects;
• assess the risks and consequences of an impact;
• implement measures to mitigate any future impacts and new national and international arrangements to cope with the many issues raised.

The need to take seriously the risk to Earth from space rocks has also been echoed by Jonathan Tate of pressure group Spaceguard UK.

He said that the risk of an impact and the widespread loss of life that would result "substantially exceeds the limits of tolerability applied by the Health and Safety Executive to the nuclear industry and the transport of hazardous goods".

When he formally receives the report, Lord Sainsbury will take several months to decide whether to act on its recommendations.