‘Death Star moon’ could be hiding underground ocean, NASA says

17 Oct 2014

NASA's Cassini spacecraft obtained this raw image of the moon Mimas on 16 October 2010, just before Mimas went into shadow behind Saturn. Image via NASA

A new study examining Saturn’s moon, Mimas, otherwise known as the ‘Death Star moon’ for its similarity to the Star Wars ship, has found it could possibly be hiding an underground ocean.

The findings, made by a team from US space agency NASA, the European Space Agency (ESA) and the Italian Space Agency (ISA), have been published in the journal Science.

The researchers who have been examining Mimas, one of Saturn’s many moons, found Mimas is by no means a stable planet and has shown itself to be wobbling.

From their understanding, this could only be caused by either its core being in the shape of an American football, or that Mimas actually hides a vast ocean beneath its icy surface.

Previous understanding of the 4bn-year-old moon has been that its heavily cratered surface suggested there was nothing particularly unusual about the satellite compared with other dead moons.

Temperature readings of Mimas in 2010 found the expected temperatures were totally different from actual readings of the moon’s surface. Image via NASA

Either way, both possibilities have excited the research team. The latter possibility, in particular, would mean Mimas becomes one of the few known planetary bodies in our solar system to inhabit an ocean, the others being two of its fellow moons, Titan and Enceladus, as well as seven of Jupiter’s moons.

From their own research models, the team led by Radwan Tajeddine from Cornell University in New York, has estimated that if there is an ocean beneath Mimas’ surface, it would be about 24km-31km below, but the researchers have yet to determine what would keep an ocean formed on such a small moon.

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Colm Gorey was a senior journalist with Silicon Republic