The Cassini has shown that Titan, a satellite of Saturn, experiences significant tidal effects on its surface. In the course of its orbit, which lasts 16 days, changes shape: the closer is the gas giant tends to of a rugby ball while closer to a sphere at the farthest point from Saturn. This variation leads to a redistribution of mass and a change in the gravitational field. This is what Cassini measured, thanks to whose data has been concluded that in order to explain the tides experienced, Titan must have a liquid ocean, probably water under the surface.
