Scientists identified the ethane lake, which is about the size of Lake Ontario on Earth, using instruments onboard the Cassini spacecraft, NASA announced Wednesday. The orbiter has been studying Saturn and its moons since 2004.
"This is the first observation that really pins down that Titan has a surface lake filled with liquid," lead researcher Robert Brown, a professor of planetary science at The University of Arizona, said in a statement.
Scientists had long theorized that hydrocarbons like ethane might rain down on Titan's surface, creating bodies of water. Cassini spotted the lake in December, NASA said, and scientists confirmed that it was liquid ethane by studying the way it absorbed and reflected infrared light.
Using data from an instrument called a spectrometer, they found that it absorbed light at exactly the wavelength that ethane does.
The ethane lake formed because sunlight breaks down methane in Titan's atmosphere. The resulting ethane then forms rainclouds, and the rain eventually cuts streams and lakes into Titan's surface, just as water does on earth.
The finding supports the idea that Titan could be a place to look for extraterrestrial life, although it would be unlike any life found on earth.
"It depends on how open a mind you have," Jonathan Lunine, a professor of planetary science at the University of Arizona who was not involved in the study, told Scientific American. "If you throw a terrestrial organism onto the surface of Titan, it will die. But there is the chance that liquid hydrocarbons could sustain exotic forms of life."
The findings were published Thursday in the journal Nature.
