Gilese 581g is 20 light years from Earth -- a near neighbor by galactic standards . Comment: it means that it orbits the star at a distance that allows for the planet to have both liquid water and an atmosphere , two conditions that are considered important for life to exist . ` Scientists believe Gilese 581g has a mass three to four times that of Earth . A habitable planet has to be a rocky planet large enough to hold an atmosphere .
Gilese 581g is 20 light years from Earth -- a near neighbor by galactic standards . Comment: Scientists believe Gilese 581g has a mass three to four times that of Earth . A habitable planet has to be a rocky planet large enough to hold an atmosphere .