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| This artist's conception illustrates Kepler-22b, a planet known to comfortably circle in the habitable zone of a sun-like star. It is the first planet that NASA's Kepler mission has confirmed to orbit in a star's "habitable zone" -- the region around a star where liquid water, a requirement for life on Earth, could persist. |
NASA announced the discovery of another planet close enough to the sun it orbits to potentially support life.
Called Kepler-22b, about 2.4 times the radius of Earth and about 600 light-years away. And it orbits in the "habitable zone," the region of space just far enough from a star that liquid water could exist on the planet's surface -- a discovery could have profound implications in the quest for alien life, said Alan Boss, an astrophysicist with Carnegie Melon University.
The host star lies about 600 light-years away from us (1 light year is about 6 trillion miles) toward the constellations of Lyra and Cygnus, the researchers said, and is about 25 percent less luminous than the Sun. Kepler-22b orbits the star every 290 days, as compared with 365 days for the Earth, at a distance about 15 percent closer to its star than the Earth from the Sun -- close enough to suggest a pleasing, balmy temperature on the surface.
Called Kepler-22b, about 2.4 times the radius of Earth and about 600 light-years away. And it orbits in the "habitable zone," the region of space just far enough from a star that liquid water could exist on the planet's surface -- a discovery could have profound implications in the quest for alien life, said Alan Boss, an astrophysicist with Carnegie Melon University.
The host star lies about 600 light-years away from us (1 light year is about 6 trillion miles) toward the constellations of Lyra and Cygnus, the researchers said, and is about 25 percent less luminous than the Sun. Kepler-22b orbits the star every 290 days, as compared with 365 days for the Earth, at a distance about 15 percent closer to its star than the Earth from the Sun -- close enough to suggest a pleasing, balmy temperature on the surface.
The planet is in the middle of what astronomers call the Goldilocks zone, that hard to find place that's not too hot, not too cold, where water, which is essential for life, doesn't freeze or boil and this new planet might well be not only habitable but perhaps even inhabited.
The discovery team, led by William Borucki of the NASA Ames Research Center, pored over photometric data from the NASA Kepler space telescope. They watched for tiny dimmings of star light -- dimmings that can only be measured by a highly specialized space telescope like Kepler -- which indicate that an Earth-size planet is transiting between us and a star.
So far the Kepler telescope has spotted 2,326 candidate planets outside our solar system with 139 of them potentially habitable ones. Even though the confirmed Kepler-22b is a bit big, it is still smaller than most of the other candidates. It is closest to Earth in size, temperature and star than either of the two previously announced planets in the zone.
Of the 54 habitable zone planet candidates spotted in February 2011, Kepler-22b is the first to be confirmed.
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