An asteroid with the destructive power of an H-bomb will narrowly miss Earth next year, scientists have said.
The 164ft-long space rock will whizz past our planet on February 15, 2013, at a distance of just 24,000km (14,913 miles), which is closer than the orbit of many commercial satellites.
Scientists say there is no chance of an impact from Asteroid 2012 DA14 but such a possibility cannot be ruled out in years to come.
If it did smash into Earth the force of the explosion would destroy an area the size of Greater London.
The asteroid was seen last month by a team in a Spanish observatory after they searched an area of the sky where asteroids are not normally seen.
Dr Gerhard Drolshagen, a near-Earth object observer from the European Space Agency's Space Situational Awareness (SSA) office, said: "The object is roughly 50m across and at that size it could do some damage if it exploded over an inhabited area.
"It would have the force of the biggest nuclear weapon."
The asteroid is expected to make its closest approach shortly after 6pm UK time.
"Next year it will be nice to watch through a pair of binoculars, but there is nothing to worry about," said Dr Drolshagen.
"In future times the possibility of a collision cannot be completely excluded. It is highly unlikely, but the chance is greater than zero."
Scientists at the SSA are developing new telescopes aimed at automatically detecting large asteroids at least three weeks before their closest approach to Earth.
In November of last year, the 400m (1,300ft) Asteroid 2005 YU55 skimmed past Earth . At one point it was just 325,000km (201,700 miles) away.
An asteroid estimated to be 40m (131ft) across exploded over Tunguska in Siberia in 1908, obliterating 2,000 square km (772 sq miles) of forest.