(CNN) -- NASA scientists revealed Friday a first-of-its-kind image from space showing reflecting sunlight from a lake on Saturn's largest moon, Titan. It's the first visual "smoking gun" evidence of liquid on the northern hemisphere of the moon, scientists said, and the first-ever photo from another world showing a "specular reflection" -- which is reflection of light from an extremely smooth surface and in this case, a liquid one. "This is the first time outside Earth we've seen specular reflection from another liquid from another body," said Ralf Jaumann, a scientist analyzing data from the Cassini unmanned space probe. Jaumann said he was surprised when he first saw the photos transmitting from Cassini, orbiting Saturn about a billion miles from Earth.
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NASA photo from Cassini probe is first-ever of liquid on another world, says scientist
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Image shows sun reflecting from a lake on Saturn's moon, Titan
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Planets with liquid are thought to be more likely to develop life
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Scientists have been studying Titan because of its similarities to Earth
Saturn
Saturn
Saturn
The photo comes from the spacecraft Cassini, which has been searching for this kind of reflection since it began circling @placeholder in 2004.
NASA
NASA
The hunt for the specular reflection took five years, @placeholder said, because the moon's northern half had been shrouded in winter darkness.