The ultimate in astronomical matters would be the discovery of a new planet similar to the Earth. This would be a whole new environment, whole new species as well as many other intriguing philosophical matters. Astronomers have found a new, potentially habitable Earth-sized planet. It is one of two new planets discovered around the star Gliese 581, some 20 light years away from our own. The planet, Gliese 581g, is located in a “habitable zone”—a distance from the star where the planet receives just the right amount of stellar energy to maintain liquid water at or near the planet’s surface.