Evidence for subsurface oceans on Titan

[steorra]

Cassini has found evidence that Titan has liquid water beneath its surface. Saturn causes tidal distortions in Titan; if Titan were solid all the way through, we'd expect to see relatively small tidal distortions, but Cassini has instead found much larger ones, which suggests that part of its interior is liquid and thus more easily distorted.

Here are two articles on the topic, one from NASA and one from ESA.