Read enough astronomy press releases, and you'll know that "habitable" is better than "earth-like," which means a certain distance from a star, which is better than "earth-sized," which could mean Venus which looks like pizza right out of the oven. So "Potentially Habitable," this is good. The planet's name is Gliese 581g, it's around three earths, it's probably not made of gas, it could conceivably hold on to an atmosphere, and it's at the right distance from its star, Gliese 581, to have liquid water on the surface. Gliese 581g for some physics reason always faces Gliese 581, so half of it may or may not be [...]