Asteroid to pass within sight of Earth

A large asteroid will pass close enough to Earth next week that amateur astronomers should be able to see it, NASA scientists said Wednesday.

Asteroid 2007 TU24 will pass within about 540,000 kilometres, or 1.4 lunar distances, of Earth early Tuesdayfor Canadians, reaching its closest approach at 3:23 a.m. ET.

The asteroid will, for a brief time, be visible to amateur telescopes of 7.5-centimetre apertures or larger, according to the Near-Earth Object program office of NASA's Jet Propulsion Lab.

The asteroid, measuring between 150 and 600 metres in diameter, has no chance of hitting or affecting the Earth, the office said.

Asteroids of this size or larger are expected to pass this close to Earth, on average, about every five years, the scientists said. Asteroids of this size hit the Earth on average once every 37,000 years, they said.

In 2002, amateur astronomers were able to observe the flight of an 800-metre-wide asteroid when it passed over North American skies at a similar distance from Earth.

On March 31, 2004, a small asteroid, designated 2004 FU162, came the closest to Earth, passing within 6,500 kilometres, or roughly one Earth radius. It was onlyfive to 10 metres in diameter, however.

Asteroid 2007 TU24 was discovered last October.NASA scientists said they plan to track and take high-resolution radar images of the asteroid as it nears Earth, with the hopes of producing a 3-D reconstruction.