Two regions on Titan have been observed to undergo clear changes in brightness. This activity, and radar images hinting at flow-like structures, suggest the presence of volcanoes. Rather than erupting molten rock, Titan's "cryovolcanoes" are thought to ooze a slurry made of water ice, ammonia and methane.
"Cryovolcanism is a process that many people have modelled in theory and shown to be viable in the outer Solar System on an object of Titan's size," said Bob Nelson from the US space agency Nasa's Jet Propulsion Laboratory.
Cassini's radar - an instrument that can pierce Titan’s the thick atmosphere to map the surface, at low resolution - sees lobe-like features at the two locations. Their thickness, about 200m, is consistent with a cyrovolcanic flow interpretation. "These flows would come out as a thick slurry," said Dr Rosaly Lopes, a Cassini radar team investigation scientist. "They can be thick because cryomagma would be viscous, similar to lava flows on Earth."
Not all scientists are convinced by the latest assessment, however. Jeffrey Moore, a Nasa planetary geologist independent of the Cassini mission, told the meeting: "The flow-like features we see on the surface may just be icy debris that has been lubricated by methane rain and transported down-slope into sinuous piles like mudflows."
Ice volcanoes or mudflows caused by methane rain, Titan sounds like a fascinating place. I wonder if I will live to see a manned mission to the moon... Possibly not