File:Capt.054a241605e445c1a3b36f66c7aa2994.habitable planet scl201.jpg

This artistic illustration released by the European Southern Observatory on Tuesday, April 24, 2007, shows planets orbiting the red dwarf star, Gliese 581. Astronomers believe that the newly discovered planet Gliese 581 c, left, is potentially habitable. (AP Photo/European Southern Observatory)