Hydrocarbon river flows across Saturn's moon Titan

ESA

Although it hasn't (and almost certainly won't) reach Voyager-level durability, the joint NASA/ESA Cassini mission has now been in space since 1997, orbiting Saturn for over eight years. The extended mission has allowed the spacecraft to get different perspectives on the planet and its many moons, as well as track features that change over time. As a result, it continues finding new things.

The latest was announced by the ESA yesterday: a 400km long river that flows into a hydrocarbon sea. Titan is cold enough that water remains frozen but warm enough that some simple hydrocarbons—ethane and methane—can remain liquid on its surface. We've previously identified lakes, small rivers, and large liquid seas on the surface of the moon, but we've not gotten these sorts of high-quality images of a large river system before.

The river shows features that wouldn't look out-of-place on Earth, such as branches and meanders. But ESA scientists suggest that large, relatively straight sections suggest the liquids may be following a fault on Titan's surface. Although there's no confirmed tectonic activity on the moon, the current plan is to continue the Cassini mission through 2017. That will give it plenty of additional chances to search for further evidence of faults on Titan's surface. (Cassini's mission will end when it's sent to burn up in Saturn's atmosphere, in order to prevent contamination of the moons.)