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The intense haze surrounding Saturn's moon Titan shrouds it from view, making it difficult to ascertain the composition of the satellite's surface. Now scientists have used two radio telescopes on Earth to peer through the smog. Their observations suggest that hydrocarbon seas could cover up to three quarters of the moon.
"The surface of Titan is one of the last unstudied parcels of real estate in the solar system, and we really know very little about it," comments Donald Campbell of Cornell University. Previous investigations conducted using other techniques hinted at the presence of methane clouds and surface water ice. In the new work, published online today by the journal Science, Campbell and his colleagues analyzed radar observations of the moon taken in November and December of 2001 and 2002. They discovered sharp spikes in the spectrum of radiation reflected off of Titan's surface that indicate the presence of smooth, dark areas 50 to 150 kilometers wide having properties consistent with organic matter such as liquid hydrocarbons. "These features may be impact craters--of which, extrapolating from other Saturnian moons, one might expect around 80 with a diameter of 150 km and thousands of smaller ones--that have filled to form lakes and seas," notes Ralph Lorenz of the University of Arizona in an accompanying commentary.
Because astronomers can currently only probe Titan from afar, uncertainty about the results remains. In October 2004, however, the Cassini spacecraft is expected to commence its first of 40 flybys of the moon. And in January 2005 it will drop the Huygens probe down to the surface, giving scientists their first look at the moon up close.