
Orbit of Gliese 581g compared to our solar system (credit: NASA)
According to new atmospheric-modeling research, the planet Gliese 581d, like its neighbor Gliese 581g, may lie in the star’s “habitable zone”—the region where a planet’s temperature can sustain liquid water on its surface. The new research supports similar studies from earlier this year.
Research suggests Gliese 581d is rocky like Earth, and probably seven to eight times the size of Earth.