next frontier

Astronomers have finally found a planet that resembles our own. According to the Associated Press report, it's "Not too far from its star, not too close. So it could contain liquid water. The planet itself is neither too big nor too small for the proper surface, gravity and atmosphere. It's just right. Just like Earth."

The planet orbits a dim red dwarf star 20 light years from Earth called Gliese 581. Four planets were already known around the star, with two lying near the inner and outer edges of the habitable zone, where liquid water – and therefore potentially life – could exist on its surface.

One of those, which travels on a 13-day orbit, seems too hot for liquid water. The other, on a 67-day orbit, may be just warm enough for liquid water, but its status is not completely settled, says scientist James Kasting of the Pennsylvania State University in University Park, who was not involved in the discovery. Opinions "may continue to swing back and forth because it is hovering right near the outer edge", he says.

The newly found "Goldilocks" planet, called Gliese 581 g, lies in between the hot and cold ones. "You're smack dab in the middle of the habitable zone, so that's perfect," says Kasting, who has studied the two planets on the zone's edges.