An asteroid some 250m (600ft) across is about to sweep past the Earth. There is no chance of it hitting the planet, but astronomers will train telescopes and radar on the object to learn as much about it as they can. The asteroid - which carries the rather dull designation 2007 TU24 - will pass by at a distance of 538,000km (334,000 miles), just outside Moon's orbit. http://news.bbc.co.uk/1/hi/sci/tech/7214524.stm