A giant space rock was set to whizz past the Earth on Monday under the close scrutiny of astronomers.
The mountain-sized object had been classed as a "potentially hazardous asteroid", but scientists say there was no danger of a collision with Earth
It was anticipated that asteroid 2004 XP14, as it is called, would be visible through good amateur telescopes.
Its closest approach to Earth, above the west coast of North America, was projected at 0444 GMT.
At this time calculations suggested it would be about 268,873 miles (432,709km) from the Earth, only 1.1 times the planet's distance from the Moon.
Radar analysis
Scientists were hoping to calculate the precise size and shape of the object by bouncing very high frequency radio waves off its surface.
POTENTIALLY HAZARDOUS ASTEROIDS
Space rocks larger than about 100m that come closer to Earth than 7.5m km
Astronomers have spotted 796 so far in this category
They are under close scrutiny to better predict any threat
This should also allow them to calculate precisely how close it came to the planet, as well as its velocity and mass, giving clues to its composition and structure.
2004 XP14 was discovered in December 2004 by telescopes run by the Lincoln Near Earth Asteroid Research (Linear) project.
Funded by the United States Air Force and the US space agency (Nasa), Linear aims to survey the sky for potentially dangerous asteroids.
Initially there were concerns that asteroid 2004 XP14 might hit Earth later this century. But after further monitoring, astronomers ruled out such a collision for the foreseeable future.
"It's not Earth-threatening," said Don Yeomans, who heads Nasa's Near Earth Object Program.
The mountain-sized object had been classed as a "potentially hazardous asteroid", but scientists say there was no danger of a collision with Earth
It was anticipated that asteroid 2004 XP14, as it is called, would be visible through good amateur telescopes.
Its closest approach to Earth, above the west coast of North America, was projected at 0444 GMT.
At this time calculations suggested it would be about 268,873 miles (432,709km) from the Earth, only 1.1 times the planet's distance from the Moon.
Radar analysis
Scientists were hoping to calculate the precise size and shape of the object by bouncing very high frequency radio waves off its surface.
POTENTIALLY HAZARDOUS ASTEROIDS
Space rocks larger than about 100m that come closer to Earth than 7.5m km
Astronomers have spotted 796 so far in this category
They are under close scrutiny to better predict any threat
This should also allow them to calculate precisely how close it came to the planet, as well as its velocity and mass, giving clues to its composition and structure.
2004 XP14 was discovered in December 2004 by telescopes run by the Lincoln Near Earth Asteroid Research (Linear) project.
Funded by the United States Air Force and the US space agency (Nasa), Linear aims to survey the sky for potentially dangerous asteroids.
Initially there were concerns that asteroid 2004 XP14 might hit Earth later this century. But after further monitoring, astronomers ruled out such a collision for the foreseeable future.
"It's not Earth-threatening," said Don Yeomans, who heads Nasa's Near Earth Object Program.
