ESA’s Paris press conference produced new images and an analysis of data from the six instruments that Huygens took to the surface of Titan. “We now have the key to understanding what shapes Titan’s landscape,” said Dr Martin Tomasko, Principal Investigator for the Descent Imager-Spectral Radiometer (DISR), adding: “Geological evidence for precipitation, erosion, mechanical abrasion and other fluvial activity says that the physical processes shaping Titan are much the same as those shaping Earth.”

That statement appears in this ESA news release, which goes on to discuss the remarkable surface features Titan has yielded up to scrutiny. And while calling Titan an ‘extraordinarily Earth-like world,’ as ESA does here, seems to be stretching the point (especially at surface temperatures cold enough to produce liquid methane), the new images,like the one below, do show a complex meteorology.

Available in both a gaseous and liquid state, methane forms clouds and precipitates onto the surface. From an article by David Noever in Astrobiology Magazine: “Instead of a base chemistry defined by hydrogen and oxygen like Earth’s, Titan offers a eroded landscape shaped by the chemistry of hydrogen and carbon. This new hydrocarbon world is frozen, choking and wind-blown.”

We’re looking at drainage channels merging into rivers and lakebeds; Huygens even spotted what appear to be off-shore islands, as can be seen in other new images at the ESA site. The rivers and lakes seem to be dry, but there is evidence rain may have fallen recently. And in what may rank as the biggest surprise of the mission, Huygens picked up atmospheric argon, evidence of volcanic activity involving water ice and ammonia.

From the news release:

Thus, while many of Earth’s familiar geophysical processes occur on Titan, the chemistry involved is quite different. Instead of liquid water, Titan has liquid methane. Instead of silicate rocks, Titan has frozen water ice. Instead of dirt, Titan has hydrocarbon particles settling out of the atmosphere, and instead of lava, Titanian volcanoes spew very cold ice.