"A giant methane-spewing volcano has been spotted in close-up images of Saturn's giant moon Titan. But the Cassini and Huygens spacecraft failed to find any signs of the expected oceans or lakes of liquid methane. The infrared images, which penetrate the perpetual deep smog of Titan, reveal the first clear signs of an unusual kind of ice volcanism. A large dome-like structure 30 kilometres across may be a “cryo-volcano” produced by an upwelling plume of hydrocarbons ices." http://www.newscientist.com/article.ns?id=dn7489
Hum, well spotted.... It should be noted that the ice volcano is inactive; though it is believed that similar volcanoes may exist elsewhere on that ooze a methane-water ice mixture to the surface. So, while the ice volcano hypothesis is intriguing, higher-resolution images could reveal that the structure could turn out to be something else other than a volcano. The next flyby of titan will be on August 22 2005.
How do you know that is inactive? I haven't read any info declaring conclusively that is inactive. The presence of methane in Titan's athmosphere cannot be explained by metahne seas, because they don't exist; volcanos spewing methane is the logical alternative, perhaps this one is doing so right now
Hum, Sry, I meant inactive when the images were taken. I think I read it from the Huygens probes landing site page (?) that the spectra/heat signature of the dome was similar to the surroundings. Yes the logical source of the methane would be the surface [directly, rather than from isolated `hot spots` - it is not known (still to be calculated) if the tidal forces from Saturn are big enough to generate volcanoes ]
Either that or it's 10,000 Wooly Titan Mammouths that live on the surface of Titan that are spewing out 'methane' from parts unknown. Novacane