An asteroid passed by Earth at a very close distance in the predawn hours of Monday, astronomers said.
The asteroid named 2004 XP14 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.
Astronomers, who have been tracking the asteroid's track since its discovery in December, 2004, said this encounter posed no threat to Earth.
The asteroid's minimum distance from Earth reached about 400, 000 kilometers Monday morning, slightly larger than the Moon's average distance from Earth, the NEO program said. Its closest approach was over the U.S. West Coast.
When it was first spotted in 2004, the asteroid's track caused astronomers to classify it as one of the 783 potentially hazardous asteroids (PHA). Initially there were concerns that this asteroid might possibly impact Earth later this century and thus merit special monitoring.
But further analysis of its orbit has since ruled out any such collision at least in the foreseeable future. 2004 XP14 will have 10 more close encounters with Earth over this century, none expected to pose a threat to the planet, astronomers noted.
The encounter on Monday has been by far the closest that this particular object will come during the rest of the 21st century.
NASA used its 70-meter radar at Goldstone, California, to yield detailed images of the asteroid, as well as highly precise values for its orbit and spin state. Astronomers will analyze radar data on 2004 XP14 over the next several days.