Article Posted on : - Jul 28, 2011

This artist's concept illustrates the first known Earth Trojan asteroid, discovered by WISE. Photo: University of Western Ontario, Canada.

WASHINGTON (BNS): NASA's Wide-field Infrared Survey Explorer (WISE) mission has discovered the first known "Trojan" asteroid orbiting the sun along with Earth, NASA said.

The asteroid named ‘2010 TK7’ was confirmed as an Earth Trojan after follow-up observations with the Canada-France-Hawaii Telescope on Mauna Kea in Hawaii.

Trojans are asteroids that share an orbit with a planet near stable points in front of or behind the planet. They constantly lead or follow in the same orbit as the planet, they never can collide with it.

Planets like Neptune, Mars and Jupiter have Trojans who share their orbit path with them. Saturn's moons also share orbits with Trojans.

According to NASA, the WISE telescope scanned the entire sky in infrared light from January 2010 to February 2011 to discover the Trojans.

The asteroid is roughly 1,000 feet (300 meters) in diameter. It has an unusual orbit that traces a complex motion near a stable point in the plane of Earth's orbit, although the asteroid also moves above and below the plane.

The object is about 50 million miles (80 million kilometers) from Earth. The asteroid's orbit is well-defined and for at least the next 100 years, it will not come closer to Earth than 15 million miles (24 million kilometers), it said.