A recently discovered small asteroid will pass by the earth on Thursday, but poses no risk of striking, US space scientists said.

The orb will come just 395,000 kilometers from earth - a hair's breadth away in astronomical terms. At its closest, it will be closer to earth than our Moon is, scientists said.

The asteroid, approximately 22 meters wide, was discovered by the Catalina Sky Survey, Tucson, Arizona. It will come nearest to earth at about 2300 GMT on Thursday.

Space officials said the "fly-by" is closer than most, although not especially rare.

"Fly-bys of near-earth objects within the moon's orbit occur every few weeks," said Don Yeomans of Nasa's Near-Earth Object Office at the Jet Propulsion Laboratory in Pasadena, California.

Nasa tracks asteroids and comets passing close to earth using both ground and space-based telescopes. Its Near-Earth Object Observations Programme, dubbed Spaceguard, discovers the objects and plots the orbits of many of them to determine if any could be potentially hazardous to earth.