The "misplaced" asteroid, known as 1998 OX4, was discovered by a team at the University of Arizona. They latched on to it for two weeks, but have since lost sight of it. Early estimates put the chances of it hitting the Earth at one in 10 million, and astronomers say there are many more objects to be concerned about. The US space agency, Nasa, lists another 178 "potentially hazardous asteroids", and is finding them at a rate of about one a week. A total of 20 have been discovered this year; 55 were identified in 1998.
Lord Sainsbury of Turville, a science minister, is expected to announce today in the House of Lords, in an answer to Lord Tanlaw, that Britain will try to set up a European effort to track potentially dangerous asteroids.
Astronomers say such a move is overdue. Dr Mark Bailey, director of Armagh Observatory, said: "The hazards of an asteroid impact haven't received due attention. When you multiply the likelihood of a collision with the potential number of deaths, you get a figure which is very like that which governments try to influence. It's comparable with the risk of a nuclear power plant meltdown: not likely but very bad if it happens."
Some people favour smashing incoming asteroids with nuclear missiles so that they are small enough to burn up in the Earth's atmosphere. Others believe this would multiply the risk.
A seven-mile-wide asteroid is thought to have triggered the extinction of the dinosaurs 65 million years ago.
Dr Duncan Steel, an expert on asteroid threats, said: "Sooner or later we will spot one which will have a one in a thousand or one in one hundred chance of hitting within 10 years. We won't be able to cover it up. The options are either to give up looking and keep your fingers crossed, or do it properly and look for them."Reuse content