Saturn’s largest moon, Titan, is indeed the complex and captivating place that planetary scientists suspected. The latest data from the Cassini-Huygens mission, including a mosaic image of the surface, show an odd bright red spot, an icy volcano, and a dark feature that may be a lake.
Scientists are baffled by the red spot, which is about the size of Ireland; it could be anything from a cloud to surface hydrocarbons. The 20-mile-wide volcano may be spewing methane. That discovery means Titan has a mechanism to rebuild its surface, which would otherwise have been flattened by constant methane rain.
But Cassini scientists are most excited by the lakelike dark area, 145 miles by 45 miles, with a smooth edge, similar to a shoreline. It presents the first preliminary evidence of liquid on the mysterious moon, thought to be similar to early Earth. In further passes by Cassini—39 are planned—scientists will measure the reflectivity of the dark splotch to see if it is liquid. If so, it is most likely a sea of hydrocarbon goo, like tar.