Habitable Planet Discovered Around Star Known As Gliese 581

OCT 05, 2010

Gliese 581 is a red-dwarf star about 20 lightyears from our solar system. On September 29, astronomers announced the discovery of two more planets orbiting Gliese 581---bringing the total so far to six. It appears that one of the two recently discovered planets, called Gliese 581g, might be a comfortable planet by human standards. It is about three or four times more massive than Earth and therefore probably has a solid surface to stand on. It is also at the right distance from the star so that it's likely to have a rather temperate climate---in particular, it probably has liquid water on its surface. This is the second time a planet orbiting Gliese 581 has excited astronomers. At the time of its discovery in 2007, Gliese 581c was thought to be the most Earth-like of all exo-planets discovered. But now most astronomers think that that planet is probably a bit hot for us humans. Shown here is a picture of the red-dwarf Gliese 581 that I took on May 4th, 2007. All six orbiting planets are contained in this picture although we can't make them out because they are all very close to the star itself and much much fainter.