C or D?

Researchers can't seem to make up there mind, especially about the controversial Gliese 581c planet, coined the most earth-like planet out there. New models created have estimated that Gliese 581c is a rampant greenhouse planet, just like Venus, although the new models have been contested.

We set our sights towards Gliese 581d, a world of as massive as eight Earths, now is a likely candidate for life. Despite the fact that it is slightly outside the habitable zone, researchers speculate that greenhouse effects may make it warm enough to support primitive life.

On the star side, Gliese 581 is a stable burning star that has been around for a few billion years. In terms of light,brightness, and heat, it is very similar to our own star and researchers believe that if life is found outside of the solar system, a star like this likely will their "sun".