NASA’s Cassini spacecraft has discovered a liquid lake the size of Earth’s Lake Ontario on the south pole of Titan, Saturn’s largest moon. Researchers say that Cassini’s instruments reveal that the chilly reservoir … Titan, is composed of a key component of crude oil — liquid ethane [Science News].
The new find supports the common belief that Titan is a promising place to look for extraterrestrial life. Some astrobiologists have speculated that life could develop in the moon’s hydrocarbon lakes, although it would have to be substantially different from known life on Earth, which requires liquid water [Wired News].
The Cassini orbiter has racked up a number of accomplishments since it began investigating Saturn and its moons in 2004, but its most exciting missions have focused on Titan, where the thick nitrogen and methane atmosphere resembles the atmosphere that existed on primordial Earth.
NASA scientists used a Cassini instrument called the “visual and infrared mapping spectrometer” to study the way the the lake reflects light, and determined that its main chemical component is ethane. Researchers think that the ethane forms when sunlight breaks down methane in Titan’s upper atmosphere. It is theorized that this ethane then forms clouds and rains onto the ground, cutting streams via erosion and pooling them into lakes [Scientific American].
The findings, which will be published tomorrow in the journal Nature [subscription required], strengthen the case for sending another lander to Titan’s surface (the Huygens probe, which made the journey to Saturn with Cassini, touched down on the surface in 2005 and transmitted data for 90 minutes). NASA and the European Space Agency have been discussing a return to Titan; this finding bolsters the case for sending a “splashdown lander,” or a floating probe, into a lake on Titan to sample its contents [Scientific American]. And there may be many potential landing spots: When researchers first caught sight of Titan’s southern hemisphere the lake was visible as a dark black spot; researchers say that similar dark spots observed in the northern hemisphere indicate that the moon’s surface is dotted with lakes of hydrocarbons.
For an in-depth look at what the Huygens probe found on Titan, take a look at the 2005 DISCOVER feature, “News From Earth’s Wayward Twin.”
Image: NASA/JPL/Space Science Institute
