( 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 . `` It was great because if you look at photos of planets , you mostly see nothing is happening . But in two hours we saw a glint of light getting brighter . '' Titan 's similarities to Earth have attracted NASA 's attention for decades . It 's the only body besides our own in the solar system that is believed to have liquid on its surface . Like Earth , Titan has an atmosphere which is mostly nitrogen . Experts believe the presence of liquid on a planet or moon improves the chances that some kind of life could develop there . The photo comes from the spacecraft Cassini , which has been searching for this kind of reflection since it began circling Saturn in 2004 . Scientists with the University of Arizona were able to use previous data from Cassini to learn details about the reflection 's location on Titan . The glint appears to be coming from the southern edge of a lake called Kraken Mare -- a massive body of methane that covers about 150,000 square miles ( 400,000 square kilometers ) . That 's larger than the Caspian Sea , which is the largest lake on Earth . The hunt for the specular reflection took five years , NASA said , because the moon 's northern half had been shrouded in winter darkness . `` Next , we want to find out more about Titan 's liquid , '' said Jaumann . `` Do we have some kind of weather there ? Do we have changes with seasons ? Does it rain ? How does the liquid methane run across the surface ? '' But Jaumann sounded a note of caution regarding the prospect of life in this case . `` The temperature on Titan 's surface is something like minus-180 degrees Celsius , '' he said . `` That means it 's very cold . But you never know . '' The project is based out of NASA 's Jet Propulsion Laboratory in Pasadena , California . This is not the first evidence of liquid on Titan . In 2008 , project members used infrared technology to discover a large lake in the moon 's southern hemisphere . But this recent discovery is a sure sign that liquid exists on the moon 's northern half . That region is believed to include larger basins that could hold more liquid .
Cassini photo from NASA probe is first -ever of liquid on another world , says scientist . Image shows sun reflecting from a lake on Kraken Mare 's moon , Pasadena . Planets with liquid are thought to be more likely to develop life . Scientists have been studying Titan because of its similarities to Earth .