It is believed that Titan, Saturn's moon may have an underground ocean of water, as well as ammonia. This was reported by the Cassini spacecraft of NASA. This was found by radar measurements which were carried of Titan's rotation.

Evidence points and leads us to believe that Titan is the nearest to our earth like surface, in the entire solar system. This was mainly due it's lakes, mountains, organic dunes etc. The Cassini has observed how Titan rotates and has been recording its changes, this provides us with an insight into what's lays beneath of Titan's surface.

Between 2005 and 2007, Cassini's Synthetic Aperture Radar made several passes over Titan. This was done in order to collect image data. With this amazing radar, it is possible to capture all the details of the surface of Titan, cutting through it's rich methane atmospheric haze. This has never ever been done before.

Radar engineers along with scientists have studied this data that has been collected from this radar, and have been able to identify around 50 different landmarks present on Titan's surface. Mountains, lakes etc were searched and located on Titan due to the data collected by this radar. It was also noticed that prominent surface features had moved by around 19 miles from the positions they had expected. This displacement of the surface features would be difficult to account for had it not been for the icy crust of the moon that was decoupled by an internal ocean from it's core. Thus the crust was able to move easily. Scientists therefore believe that deep below these miles of ice, an internal ocean of water which is mixed with ammonia is present.

This study of Titan is extremely important as it many contain chemical compounds that had preceded life on earth – all this in deep freeze. The only moon that is present in the solar system that has a dense atmosphere is Titan, this atmosphere is almost 1.5 times denser than that of the Earth. In fact, Titan is the largest moon of Saturn, even larger than the planet of Mercury.
While there is a lot more research and findings to be done...one can only imagine the implications of what this would mean, should there be an ocean beneath Titan's crust!