Washington, Dec 6: In another step toward finding Earth-like planets that may hold life, NASA said on Monday its Kepler space telescope has confirmed its first-ever planet in a habitable zone outside our solar system.
French astronomers earlier this year confirmed the first exoplanet to meet key requirements for sustaining life, known as Gliese 581d, but Kepler 22b, initially glimpsed in 2009, is the first the US space agency has been able to confirm.
Confirmation means that astronomers have seen it crossing in front of its star three times. "Fortune smiled upon us with the detection of this planet," said William Borucki, Kepler principal investigator at NASA Ames Research Center.
"The first transit was captured just three days after we declared the spacecraft operationally ready. We witnessed the defining third transit over the 2010 holiday season."
Kepler-22b is 600 light-years away, and is larger than Earth with an orbit of 290 days around a sun-like star.
NASA also announced that Kepler has uncovered 1,000 more potential planets, twice the number it previously had been tracking, according to research being presented at a conference in California this week.
Kepler is NASA's first mission in search of Earth-like planets orbiting suns similar to ours.
It launched in March 2009, equipped with the largest camera ever sent into space, a 95-megapixel array of charge-coupled devices, and is expected to continue sending information back to Earth until at least November 2012.
It is searching for planets as small as Earth, including those orbiting stars in a warm, habitable zone where liquid water could exist on the surface of the planet.