Newfound planet is best candidate yet for life

Posted by Kate Taylor

Scientists with NASA's Kepler mission say they believe they've found the most Earthlike exoplanet yet.

Earlier this week, they announced that they'd identified 461 new planet candidates, four of which are less than twice the size of Earth and orbit in their sun's habitable zone, where liquid water might exist on the surface.

However, it now appears that one of these, KOI-172.02, is the closest analogue to Earth yet found. Itlies in the habitable zone of a G-type star similar to our sun and is just 1.5 times the radius of Earth, orbiting its star every 242 days.

"There is no better way to kickoff the start of the Kepler extended mission than to discover more possible outposts on the frontier of potentially life bearing worlds," says Christopher Burke, Kepler scientist at the SETI Institute in Mountain View, California.

KOI-172.02 orbits its star at a distance of abut 70 million miles, a little tighter than Earth's orbit of 93 million miles from our sun. However, its star is slightly cooler than our own, giving the planet a comparable temperature to Earth's and allowing the presence of liquid water. It has an orbit of 242 days.

These discoveries, though, by no means guarantee that the planet is suitable for life. Its mass isn't known, and therefore nor is its density, and there's no information on its atmosphere.