Scientists say a world that’s 490 light-years away qualifies as the first confirmed Earth-sized exoplanet that could sustain life as we know it — but in an environment like nothing we’ve ever seen.
The planet, known as Kepler-186f, is “more of an Earth cousin than an Earth twin,” Elisa Quintana, an astronomer at the SETI Institute at NASA Ames Research Center, told the journal Science. Quintana is the lead author of a report on the planet published by Science this week.
“This discovery does confirm that Earth-sized planets do exist in the habitable zones of other stars,” Quintana said during a Thursday news briefing at NASA Headquarters.
Kepler-186f goes around an M-type dwarf star that’s smaller and cooler than our sun. But it orbits much closer to its parent star than Earth does, within what would be Mercury’s orbit in our own solar system. Those two factors combine to produce an environment that could allow for liquid water on the surface, assuming that the planet had a heat-trapping atmosphere.