Earth-sized planet found in Earth's backyard

LONDON/CAPE CANAVERAL (REUTERS) - Astronomers have found a new planet, the closest yet outside our solar system and just an astronomical stone's throw away at four light years, raising the chances of finding a habitable planet in Earth's neighbourhood.

Researchers say the new planet is too close to its sun to support known forms of life, with a surface temperature estimated at 1,200 degrees Celsius. But previous studies suggest that when one planet is discovered orbiting a sun, there are usually others in the same system.

The new Earth-sized planet, announced in science journal Nature by Dr Stephane Udry and Dr Xavier Dumusque at the Geneva Observatory, orbits one of the suns in Alpha Centauri, roughly 25 trillion miles away.

"It's a landmark discovery because it's very low mass and it's our closest neighbour," said Dr Udry. "Its orbit is very close to its star and it must be much too hot for life as we know it, but it may well be just one planet in a system of several."