Astronomers revealed about Gliese 581d in 2009 with the exoplanet being described as a super-Earth that has the possibility of harboring liquid water on its surface.
A 2014 research, however, has casted doubts about the existence of this alien world with the study suggesting that the data that was used to find it may have been misinterpreted signals from the stars.
Although nearly 2,000 extraterrestrial worlds beyond the solar system have so far been discovered, the search for a true Earth analog remains to be in its infancy so some exoplanets discovered were technically not discoveries at all but mere noise in astronomical data sets.
For the same reason, researchers who revisited the evidence of Gliese 581d dismissed the existence of the planet as a stellar activity that masquerades as a planet. The exoplanet was detected after astronomers used a spectrometer to measure the small changes in the wave length of the light from the red dwarf star that Gliese 581d orbits and which is believed could host four other additional planets.