National Science Foundation artist, Lynette Cook's drawing shows the inner four planets orbiting Gliese 581, a red dwarf star just 20 light-years from Earth. The newly discovered planet, in the foreground, has a 37-day orbit and, like Earth, is distant enough from the star for liquid water to exist.
![All of the planets orbiting Gliese 581 are nearer to it than the Earth is to our sun.](http://media.npr.org/assets/img/2010/09/29/exoplanet_wide.jpg?t=1285783651&s=3) |
Zina Deretsky/National Science Foundation
![All of the planets orbiting Gliese 581 are nearer to it than the Earth is to our sun.](http://media.npr.org/assets/img/2010/09/29/exoplanet_orbit_comparison_custom.jpg?t=1285783733&s=2) |