This artist’s impression shows a planet orbiting the star Alpha Centauri B, a member of the triple star system that is the closest to Earth. Other Earth-like planets have been found before, but this one, announced on Oct. 16, 2012, is far closer than previous discoveries but still too hot for life and more than 25 trillion miles away.
ESO, L. Calcada/AP
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This artist rendering provided by NASA shows Kepler-11, a sun-like star around which six planets with the possibility of alien life orbit.
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This artist rendering provided by NASA shows a comparison of the Kepler-11 solar system and ours.
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An artist rendering shows a rocky planet called Kepler-10b found by NASA’s Kepler telescope. Planets with the possibility of alien life are proving more common outside our solar system than once thought.
Dana Berry, SkyWorks Digital Inc., Kepler Mission, NASA Ames Research Center/AP
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Kepler-22b, a planet known to comfortably circle in the habitable zone of a sun-like star, is shown in an artist rendering for NASA.
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This illustration shows artist's renderings of planets Kepler-20e and Kepler-20f compared with Venus and the Earth.