By Dr David Whitehouse
BBC News Online science editor
Astronomers have watched a small object make the closest approach to the Earth of any space rock yet observed.
Small but close, as seen by the Starkenburg Observatory
The asteroid, called 2004 FH and about 25m wide, passed by at a distance of just 43,000km at 2208GMT on Thursday.
Scientists say there was never any danger of the Earth being struck by the object, which was found by an automated sky survey on Tuesday.
Astronomers believe they are getting much better at finding the smaller rocks that make close approaches.
It gives them more confidence they will detect the more dangerous asteroids on a potential collision course with Earth. If 2004 FH had struck the planet, it would probably have burnt up in the atmosphere.
The asteroid, which was discovered by the Linear sky survey based in New Mexico, made the pass while streaking over the southern Atlantic Ocean.
Astronomers took the opportunity to get a rare, close-up view of an asteroid.
It should have been visible through binoculars to stargazers across the Southern Hemisphere, as well as throughout Asia and Europe.
Scientists have not ruled out the possibility that the asteroid and our planet could meet again sometime in the future.
Some experts have doubted the object is really a space rock, suggesting it could be a discarded rocket booster.