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New analysis of data from the Cassini spacecraft suggests that Mimas, a moon orbiting Saturn, may have a liquid ocean beneath its icy surface. This conclusion was reached by a team of astronomers led by Valery Lainey based on a detailed analysis of Mimas's orbital motion.
"The presence of these long-lived global oceans is generally betrayed by surface modification owing to internal dynamics. Hence, Mimas would be the most unlikely place to look for the presence of a global ocean. Here, from detailed analysis of Mimas's orbital motion based on Cassini data, with a particular focus on Mimas's periapsis drift, we show that its heavily cratered icy shell hides a global ocean, at a depth of 20-30 kilometres," the paper published in Nature this week said.
The discovery of a sub-surface ocean on Mimas adds to the list of ocean worlds in the solar system and changes the understanding of what these moons can look like. Matija Ćuk and Alyssa Rose argue that the idea of relatively small, icy moons harboring young oceans is inspiring and may indicate transformational processes occurring in the recent history of these moons.
"The idea that relatively small, icy moons can harbor young oceans is inspiring, as is the possibility that transformational processes have occurred even in the most recent history of these moons. Lainey and colleagues' findings will motivate a thorough examination of midsized icy moons throughout the Solar Sys.