New Titan data suggest that Titan may hold a subsurface liqiud ocean

On the basis of gravity and radar observations with the Cassini spacecraft, the moment of inertia of Titan and the orientation of Titan's rotation axis have been estimated in recent studies.  However, the observed obliquity is inconsistent with the estimate of the moment of inertia for an entirely solid planetary body suggesting that Titan is probably not an enturely solid body

Therefore a group of scientist has proposed a new model for the interior of Titan, in which they assume the presence of a liquid water ocean beneath an ice shell and consider the gravitational and pressure torques arising between the different layers of the satellite.

The new model, have a closer agreement between the moment of inertia and the rotation state than for the solid case, strengthening the possibility that Titan has a subsurface ocean.

Source: arXiv