Tiny moon, big ocean: THIS is how a huge ocean was created on Saturn's 'Death Star' moon Mimas

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New research published in the journal Planetary Science Letters suggests that the ocean may have something to do with how Mimas orbits around Saturn

Earlier this year, a team of researchers had discovered that hiding beneath the surface of Saturn's icy moon Mimas was a huge ocean, accounting for almost half its volume. Now, the same team may have identified how the huge water body was created.

Creation of an ocean

New research published in the journal Planetary Science Letters suggests that the ocean may have something to do with how Mimas orbits around Saturn.

Researchers speculate that Mimas, which currently has a thin icy shell, once had a thick frozen exterior. However, as the moon's orbit around the ringed planet became less flattened or "eccentric" due to Saturn's pull, the icy shell melted and thinned.

This, the researchers say, around two to 25 million years ago created a vast subsurface ocean, which is relatively young for a solar system feature. 

"In our previous work, we found that for Mimas to be an ocean world today, it must have had a much thicker icy shell in the past. But because Mimas' eccentricity would have been even higher in the past, the pathway to get from thick ice to thinner ice was less clear," said the research team leader Matthew E. Walker in a statement.

"In this work, we showed that there is a pathway for the ice shell to be thinning currently, even as the eccentricity is dropping due to tidal heating. However, the ocean must be very young, geologically speaking," added Walker, who's a senior scientist at the Planetary Science Institute.

The moon nicknamed 'death star' due to the Herschel crater, which gives it an appearance resembling the Empire's moon-sized space station in Star Wars, has a diameter of just around 148 miles (238.18 kilometres). This means it is around eight times smaller than Earth's moon, which has a diameter of 2,159 miles (3,474.57 kilometres). 

Its ocean is located around 20 to 30 kilometres beneath the ice crust surface and is estimated to be 40 to 45 kilometres deep, thereby accounting for as much as half of Mimas' volume. 

(With inputs from agencies)

Moohita Kaur Garg

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