Ethane clouds found on Titan

September 18, 2006

The spacecraft Cassini-Huygens has discovered ethane clouds using the Visual and Infrared Mapping Spectrometer [VIMS] on Saturn's moon, Titan. The spacecraft also suggested that ethane "rain" and "snow" may be falling from the clouds into liquid methane lakes.

"Our observations imply that surface deposits of ethane should be found specifically at the poles, rather than globally distributed across Titan's disk as previously assumed. That may partially explain the lack of liquid ethane oceans and clouds at Titan's middle and lower latitudes," University of Arizona planetary scientist Caitlin Griffith in a statement on the Cassini-Huygens website.

"We think that ethane is raining or, if temperatures are cool enough, snowing on the north pole right now. When the seasons switch, we expect ethane to condense at the south pole during its winter," added Griffith.

Cassini recently took pictures of what scientists call "lakes and oceans" on Titan and scientists now believe that the oceans, filled with methane, may also be "rich" with ethane.

"We now know that Titan's surface is largely devoid of lakes and oceans. During the polar winters, we expect the lowlands to cradle methane lakes that are rich with ethane. Perhaps these are the lakes recently imaged by Cassini," said Griffith.

VIMS first detected the clouds during flybys in December 2004 and September and August 2005.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency.