Ocean likely below Saturn's moon Titan

A vast ocean of water and ammonia may lurk deep beneath the surface of Titan, the intriguing orange moon of Saturn already known for its blanket of clouds and dense atmosphere.

Astronomers have not directly observed this ocean, but they say observations made by the Cassini spacecraft of Titan's rotation and shifts in the location of surface features suggest an ocean exists perhaps 100 kilometres under the surface.

Titan is Saturn's largest moon and the second biggest in the solar system, only slightly smaller than Jupiter's moon Ganymede. Titan's diameter of about 5,150 kilometres is larger than the planet Mercury and the dwarf planet Pluto.