Earlier this week, scientists with NASA's Kepler mission announced that they had 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 could exist on the surface. It appears that one of these four planets, KOI-1072.02, may be the closest analogue to Earth to be found to date.
KOI-172.02 lies 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.
Christopher Burke, a Kepler scientist at the SETI Institute in Mountain View, Calif., said:
"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."
KOI-172.02 orbits its star at a distance of around 70 million miles, which is slightly tighter than Earth's orbit of 93 million miles from our sun. It's star is slightly cooler than our own, which gives the planet a temperature pretty comparable to Earth's and allows for the presence of liquid water.
The planet's mass is not known, nor is its density, and there is no information on its atmosphere. So while it may appear quite similar to Earth, until more information is obtained, there are no guarantees that it is actually suitable for life.