Watery secret could be lurking beneath Saturn's 'Death Star' moon

Scientists have discovered a tiny moon of Saturn, named Mimas, may be hiding an ocean of liquid beneath its cratered surface.

The surprise findings published in the journal Nature means astronomers may have to overhaul their understanding of watery worlds in space.

Mimas has been nicknamed the "Death Star" moon due to its uncanny resemblance to the iconic Star Wars battle station.

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The internal ocean beneath its cratered surface was revealed in data collected by the final dive of the Cassini spacecraft into Saturn in September 2017.

Astronomers believe that the ocean lies beneath an icy shell about 20km to 30km deep.

Simulations suggest that it appeared between 25 and 2 million years ago.

Such a timeframe meant signs of a subsurface ocean would not have had time to make a mark on the surface.

Previous theories held that a hidden ocean on Mimas was unlikely because of its surface qualities which are different to other icy moons that hold liquid water, such as Enceladus.

But the new research suggests the evolution of its orbit is better explained by the influence of an internal ocean and Mimas may have more in common with other icy worlds.

Mimas was discovered by German-born astronomer William Herschel on September 17, 1789.