Cassini scans lunar lakes

The hunt for massive liquid oceans on Titan may have come up dry. But not so with efforts to explore the moon’s large lakes.

Scientists touring Saturn’s largest moon via the Cassini orbiter have found strong evidence for liquid ethane in Ontario Lacus (Lake Ontario). It’s a Great Lake-size body of liquid pooled near Titan’s South Pole.

This is the first time Cassini has been able to tease out the composition of liquids in these lakes. The presence of liquid ethane, the research team says, probably means methane, nitrogen, butane, and propane are also part of the lake’s hydrocarbon soup.

Ontario Lacus is not the first lake Cassini has detected. Two years ago, scientists reported the discovery of several lake-dotted regions in the moon’s northern hemisphere. But lighting and viewing angles at the time obscured the spacecraft’s Visual and Infrared Mapping Spectrometer, which picks up information on surface composition. For Ontario Lacus, however, conditions were just right.

In addition to the lake’s composition, the lake’s broad shoreline and beach-like features were readily visible.

The team, led by University of Arizona planetary scientist Robert Brown, says it hopes to get a good look at lakes in Titan’s northern hemisphere in a couple of years, after the north enters its “spring.”

The results appear in today’s issue of the journal Nature.