An asteroid will pass Earth at a very close distance in the predawn hours of Monday, astronomers reported on Friday, noting that there won't be any danger of collision.

The asteroid, coded 2004 XP14, was first picked up in December 2004. It is believed to be 370 to 800 meters in diameter, according to astronomers with the Near Earth Object Program (NEO) of U.S. space agency NASA.

When it was first spotted, the asteroid was farther away from Earth, but the character of its orbit caused astronomers to classify it as one of the 783 potentially hazardous asteroids (PHA) by the Minor Planet Center in Cambridge, Massachusetts.

Although initially there were concerns that this asteroid might possibly impact Earth later this century and thus merit special monitoring, further analysis of its orbit has since ruled out any such collision at least in the foreseeable future.

The upcoming flyby is only moderately close, noted the astronomers. The asteroid's minimum distance from Earth will be about 400, 000 km Sunday midnight, slightly larger than the Moon's average distance from Earth. Its speed will reach 17 km per second.

"There is no risk of its hitting either the Earth or the Moon, but it is unusually well placed for study, especially by radar," the NEO said in a statement.

This is by far the closest that this particular object will come during the rest of the 21st century. For a few hours it will be as bright as 11th magnitude, making it easily visible to sky watchers with a 20-cm or larger telescope.

Extensive observations are planned with the NASA 70-m radar at Goldstone, California, which is part of the NASA Deep Space communications network. It is anticipated that these radar studies will yield detailed images of the asteroid, as well as highly precise values for its orbit and spin state.

The close pass by such a large asteroid has little historical precedent, but calculations show that a Near Earth Asteroid this large comes this close about once per decade on the average. However, similar close passes in the past were not observed, astronomers said.

Source: Xinhua