Gliese 581g

Gliese 581g - A red dwarf star located a mere 20 light-years away in the constellation Libra. Earthbound telescopes had detected the signatures of multiple planets orbiting the cool sun, two at least close to the system's habitable zone - the region where an Earth-like planet can have liquid water on its surface. There is now a detection of another planet, this one squarely in the system's habitable zone - the first potentially habitable planet found around a very nearby star. Shown in this illustration of the inner part of the exoplanetary system, the planet is designated Gliese 581g. The best fit to the data indicates the planet has a circular 37 day orbit, and a mass 3.1 times the Earth's. Finding a habitable planet so close by suggests there are many others in our Milky Way galaxy. — at Illustration Credit: Lynette Cook/NASA.