"It's amazing that so far away, with such exotic materials, there's this hydrological cycle that's occurring that we dont see anywhere else in the solar system but on Earth," she said.
"If you were standing on the shores of these lakes, in some ways they would look familiar," she added.
"The methane would be transparent, so you could see pebbles on the bottom. And the largest lake is 70 kilometers [43 miles] across, so there's probably enough [distance] for waves to form."
In fact, she said, some of the radar images appear to show that the lake surfaces are choppier near the shores, a possible indicator of wave action.
The next step, Stofan said, is to watch how the lakes change as Titan's 29-year-long seasonal cycle switches from winter to spring.
Learning more about Titan's methane cycle will help us understand our own planet better, added Christophe Sotin of the University of Nantes in France.
"Titan is the only other place in the solar system where liquid is present at the surface," Sotin said by email.
Liquids are believed to be necessary for life.
"On Titan we don't expect life at the surface, because the temperature is too small—minus 179 degrees Celsius [minus 290 degrees Fahrenheit]," Sotin said.
But, he added, the study of methane helps us understand the processes that allow the existence of any liquid, including water. For liquids to persist for billions of years, for example, there must be a long-term equilibrium between such forces as evaporation and rainfall.
"By studying Titan, we may better understand the evolution of any planet, including Earth," he said.
Cassini is slated to study Saturn and its moons until at least June 2008.
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