490 light years away
490 light years away lies Kepler-186f, a rocky world orbiting a red-dwarf star which is the first definitive Earth-sized planet found in the habitable zone around its parent star, the temperature at which water is at its liquid phase and organic life becomes a possibility.
The Kepler exoplanet-hunting telescope run by the National Aeronautics and Space Administration discovered the new planet, one of five in orbit around the red dwarf star Kepler-186. All of the others 186(b-e) are closer to their red sun 186a and are outside the habitable zone
Planet 186f has a radius that is 1.1 times the radius of Earth. “This is an historic discovery of the first truly Earth-size planet found in the habitable zone around its star,” University of California, Berkeley astronomer Geoff Marcy, who is unaffiliated with the new research, said. “This is the best case for a habitable planet yet found. The results are absolutely rock solid. The planet itself may not be [rocky], but I’d bet my house on it. In any case, it’s a gem.”
Planet 186f resides within its star’s habitable zone, but scientists still aren’t sure what the planet’s atmosphere consists of, and they cannot say with certainty that this alien world could support life. The planet is Earth-sized, but it might not be Earth-like.
“Some people call these habitable planets, which of course we have no idea if they are,” Kane said in a statement. “We simply know that they are in the habitable zone, and that is the best place to start looking for habitable planets.”