Methane smog enshrouds Titan, Saturn's mysterious moon. Because of that smog, researchers have surmised that liquid methane should exist on the surface, but probes had failed to find any. Recent radar imaging by the Cassini space probe, however, has now uncovered 75 lake-like areas, some spanning 70 kilometers, near the northern pole. Scientists believe these to be liquid-filled depressions, because the temperature (−179 degrees Celsius) and pressure (1.5 times that at Earth's surface) there are ripe for liquid methane and its breakdown product, ethane, to persist. The lakes may fill up either from liquid stored underground or through evaporation and subsequent hydrocarbon rain. Future flybys should reveal how the lakes vary seasonally, as well as whether lakes exist elsewhere on Titan's surface. The report appears in the January 4 Nature.
@dbiello Biello is the award-winning senior reporter for environment and energy at Scientific American. He has also written on subjects ranging from astronomy to zoology for both the Web site and magazine. He has been reporting on the environment and energy since 1999--long enough to be cynical but not long enough to be depressed. He is a contributor to the Instant Egghead video series, 60-Second Science podcasts, and host of "Beyond the Light Switch" as well as a forthcoming documentary on ethanol for PBS. He is the author of a children's book on bullet trains and is currently working on a book for grown-ups about whether the Earth has entered a new geologic epoch thanks to people's impacts and what should be done about this Anthropocene.