That is the first planet confirmed in the habitable zone for Kepler, which already had found Earth-like rockyplanets 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 Earth's solar system, said in an email. "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, has key aspects it shares with Earth. It circles a star that could be the twin of Earth's sun and at just about the same distance. The planet's year of 290 days is even close to Earth's. It probably has water and rock.
The only trouble is the planet's a bit big for life to exist on the surface. The planet is about 2.4 times the size of Earth. It could 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 in a phone interview.
Kepler cannot 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.
0 comments:
Post a Comment