Der er tidligere proklameret at stjernesystemet Gliese 581 havde planeterne Gliese 581 d, Gliese 581 f og Gliese 581 g, men en nærmere undersøgelse viste at de ikke fandtes.[1][2]
Opdagelsen af den formodede planet blev annonceret september 2010. Ved opdagelsen var forskere af den opfattelse, at det var den indtil da mest jordlignende planet der til dette tidspunkt var fundet. Siden er i december 2011 opdaget exoplaneten Kepler-22b, der (hvis Kepler22-b er en klippeplanet) anses at have flere ligheder med Jorden.
Schweiziske forskere har dog slået tvivl om eksistensen af Gliese 581 g, og planeten er endnu ikke endeligt bekræftet i Extrasolar Planets Encyclopaedia.[5]
^Jul 03, 2014, phys.org: Controversial clues of two 'Goldilocks planets' that might support life are proven false Citat: "...This image shows the location of the three planets remaining in 2014 after a series of studies since 2004. Research published in 2014, led by Penn State astronomers, shows that two of the signals previously attributed to planets in the habitable zone are actually created by activity within the star itself..."The disappearance of these two signals after correcting for the star's activity indicates that these signals in the original data must have been produced by the activity and rotation of the star itself, not by the presence of these two suspected planets..."
