Titan, the largest of Saturn's moons, has lakes around its equator, new results from NASA's Cassini probe shows.
Scientists previously thought puddles and lakes could only form in the moon's polar regions. Like Earth, Titan has hydrology cycles, with methane or ethane, taking on the role of water.
The surprising discovery begs the question of where the liquid came from. Cassini has only found it raining in Titan's equatorial regions once, leading scientists to suspect that the lakes aren't being replenished by rainfall.
"A likely supplier is an underground aquifer," said Cassini scientist Caitlin Griffith, with the University of Arizona, Tucson. "In essence, Titan may have oases."
The lakes were found in a tropical region known as Shangri-La, near where the European Space Agency's Huygens probe landed in 2005. One of the lakes appears to be about half the size of Utah's Great Salt Lake, with a depth of at least 3 feet.
"We had thought that Titan simply had extensive dunes at the equator and lakes at the poles, but now we know that Titan is more complex than we previously thought," Linda Spilker, Cassini project scientist at NASA's Jet Propulsion Laboratory, said in a statement.
"Cassini still has multiple opportunities to fly by this moon going forward, so we can't wait to see how the details of this story fill out," she said.
The research appears in this week's Nature.
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Image: Saturn's rings backdrop the planet's largest moon. The dark region is Shangri-La, which surprisingly has lakes. Credit: NASA/JPL-Caltech/Space Science Institute