Best candidates yet found for habitable worlds, including two potentially life-friendly planets orbiting same star.
Two of the five planets orbiting a sun-like star called Kepler-62 are squarely in what astronomers call the habitable zone, researchers said in the journal Science as was reported on Thursday.
The habitable zone refers to planets that are are neither too hot nor too cold, and could possibly contain water.
"These two are our best candidates that might be habitable," said William Borucki, Kepler science principal investigator at NASA's Ames Research Centre.
The two planets are slightly larger than ours, and at least a couple of billion years older.
The first, 62e, is about 40 percent larger than Earth. It might be warm and may experience flashes of lightning, said Borucki.
The second, 62f, is about 60 percent larger than our planet, and orbits its star every 267 days, close to Earth's annual trajectory of 365 days.
The planet may have polar caps, significant land masses and liquid water, Borucki said.
Both are orbiting a seven-billion-year-old star some 1,200 light years from Earth in the constellation Lyra.
They are close enough to their star to be warm, but not so near as to boil the oceans. They are far enough to maintain the likelihood of water without freezing the seas solid, Borucki explained.
Computer models indicate the two planets, likely are solid bodies comprised of rock, ice or a mix of rock and ice.