An asteroid up to half a mile wide is due to brush past the Earth early today by approaching almost as close as the Moon.
In astronomical terms, that counts as a near miss. But scientists who had been tracking the path of asteroid 2004 XP14 are not worried.
They knew that the space rock, travelling at 17 kilometres per second, would not hit the Earth. Nevertheless 2004 XP14 has been classified as a Potentially Hazardous Asteroid along with 782 known others.
The object, discovered in December 2004, is one of a class of "Apollo" asteroids whose orbits cross that of the Earth.
Initially there were concerns that the asteroid might collide with the Earth later this century. However, further analysis of its orbit has ruled this out - at least for the foreseeable future.
If XP14 did hit the Earth the effects would be devastating. "It would probably be big enough to wipe out a small country," said Dr David Asher, from the Armagh Observatory in Northern Ireland.
Scientists hope to gather valuable information about the asteroid by bouncing radar signals off it; this will allow them plot future orbits much more accurately and may help determine the rock's shape.
PA