"Earthlike planet is discovered" December 06, 2011|By Seth Borenstein, Associated Press
WASHINGTON - A newly discovered planet is eerily similar to Earth and is sitting in another solar system in what seems to be the ideal place for life, except for one hitch. It’s a bit too big.
The planet is smack in the middle of what astronomers call the Goldilocks zone, a place that’s not too hot, not too cold, where water, which is essential for life, doesn’t freeze or boil. And it has a temperature near 72 degrees, scientists say.
The planet’s confirmation was announced yesterdayby NASA along with other discoveries by its Kepler telescope, which was launched on a planet-hunting mission in 2009.
That is the first planet confirmed in the habitable zone for Kepler, which had already found Earthlike rocky planets elsewhere. Twice before astronomers have announced a planet found in that zone, but neither has been as promising.
“This is a phenomenal discovery in the course of human history,’’ Geoff Marcy of University of California, Berkeley, one of the pioneers of planet-hunting outside our solar system, said in an e-mail. “This discovery shows that we Homo sapiens are straining our reach into the universe to find planets that remind us of home. We are almost there.’’
The new planet - named Kepler-22b - shares key aspects with Earth. It circles a star that could be the twin of our sun and at just about the same distance. The planet’s year of 290 days is even close to ours. It probably has water and rock.
The only trouble is that the planet is a bit big for life to exist on the surface. The planet is about 2.4 times the size of Earth, and may be more like the gas-and-liquid Neptune, with only a rocky core and mostly ocean.
“It’s so exciting to imagine the possibilities,’’ said Natalie Batalha, the Kepler deputy science chief.
Floating on that “world completely covered in water’’ could be like being on an Earth ocean and “it’s not beyond the realm of possibility that life could exist in such an ocean,’’ Batalha said.
Kepler can’t find life itself, just where the conditions might be right for it to thrive. And when astronomers look for life elsewhere they are talking about everything ranging from microbes to advanced intelligence that can be looking back at us.
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