An artist's conception of the tiny alien planet Kepler-37b, which is slightly larger than Earth's moon and orbits its host star every 13 days. It likely has a surface temperature of in excess of 400 ... more 
An artist's conception of the tiny alien planet Kepler-37b, which is slightly larger than Earth's moon and orbits its host star every 13 days. It likely has a surface temperature of in excess of 400 deg C (700 deg F). Image released Feb. 20, 20 less 
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SPACE.com | Photo By NASA/Ames/JPL-Caltech
Wed, Feb 20, 2013 1:36 PM EST