Astronomers Find Earth's 'Cousin' Kepler-186f is called the best bet yet to hold alien life By John Johnson, Newser Staff Posted Apr 17, 2014 5:05 PM CDT 60 comments Comments This artist's rendering provided by NASA shows an Earth-sized planet dubbed Kepler-186f orbiting a star 500 light-years from Earth. (AP Photo/NASA Ames, SETI Institute, JPL-Caltech, T. Pyle) (Newser) – Other "Earth-like" planets have been discovered before, but a new one is generating a lot of excitement in astronomy circles because of how very Earth-like it actually is. Introducing Kepler-186f, which is maybe 10% bigger than our planet and thought to be in the not-too-hot and not-too-cold range that would make water—and life—possible. "This is the best case for a habitable planet yet found," says a Berkeley astronomer not involved with the discovery. "The results are absolutely rock solid." The planet is about 490 light-years away in the constellation Cygnus, and it circles a red dwarf star, reports AP. One known difference: Its year is only about 130 days. "One of the things we've been looking for is maybe an Earth twin, which is an Earth-size planet in the habitable zone of a sunlike star," Kepler scientist Tom Barclay tells Space.com. This one largely fits the bill. "So, while it's not an Earth twin, it is perhaps an Earth cousin." A SETI Institute researcher tells the Atlantic that the idea of finding alien life is "no longer in the realm of science fiction." That's because even if Kepler-186f proves to be a bust in the life-supporting department, its discovery suggests that lots more similar planets are out there waiting to be found, reports the LA Times. It quotes another SETI researcher calling this a "tip-of-the-iceberg discovery."