It is a planet only about 3 times the mass of Earth orbiting in the habitable zone of the star Gliese 581. It is widely considered the most likely extrasolar planet to harbor life.
Gliese 581 g was discovered on September 29, 2010.
3-6. The 3 planet model would have gliese 581 b too hot, gliese 581 c in the habitable zone, and gliese 581 d too cold. The 6 planet model would have gliese 581 e, b, and c too hot, gliese 581 g and d in the habitable zone, and gliese 581 f too cold.
No. g liese 581c is a planet that orbits a star, Gliese 581.
Because Gliese 581 g, if it exists, is located near the middle of the habitable zone (or Goldilocks zone - [See related question]) of its parent star.
Goldilocks Zone or Goldilocks Planet.
January 12th 2017
Otherwise known as Zarmina's world, Gliese 581 G is apparently of the condition to sustain life. It is an estimated 20.3 light years away. It orbits around a red dwarf called Gliese 581. For more info check out the related link
20.5 Light Years away from Earth.
Gliese itself does not exist, but Gliese 581 is a red star.
The most likely candidates are (in no order): Gliese 581 g, HD 40307 g, Gliese 163 c, Gliese 581 d, Tau Ceti e, Gliese 667C c, Kepler 22 b, HD 85512 b and Tau Ceti f
No. At 20.5 light years from Earth, and it only having been discovered, AND Terrans not having developed extra-light speed craft or wormhole technology, it would not be possible for anyone to have arrived at Gliese 581 G yet.
Earth is similar to Gliese 581 c, in that they both are the third planet from their sun. See related links for information about Gliese 581 c.