Planet - Gliese 581c

Gliese 581c , is one of the most Earth-like planet discovered to date. It is the third of four planets orbiting the red dwarf Gliese 581, 20.5 light years away, completing each orbit in a mere 13 days. Significantly, it is one of the smallest known exoplanets, measuring only 1.5 times the Earth's diameter and only 5 times its mass, and it is almost certainly a rocky world like our own. Even more suggestively it orbits close to the band around its star known as the "habitable zone," the only region where conditions are mild enough that water can exist in liquid form. Move closer to the star and all water will turn to vapor; move further away and water will turn to ice. But near the habitable zone water can remain liquid and life as we know it could potentially exist.

A small rocky planet with a mild climate where water can flow? Sounds a lot like our own world, and brings us one step closer to the discovery we are waiting for: another Earth, orbiting a distant Sun.

Links:

http://en.wikipedia.org/wiki/Gliese_581_c

http://apod.nasa.gov/apod/ap070502.html