The scientists have found an ocean in a surprising place, beneath the icy surface of Mimas, one of Saturn’s mid-sized moons. Mimas thus joins the growing list of icy moons that harbor oceans of liquid water beneath their surface.

This discovery is especially surprising because Mimas, with its 400 kilometers in diameter, exhibits a geology that did not betray the presence of a buried ocean.

Unlike other celestial bodies like Europa and Enceladus, Mimas shows no fractures or geothermal activity. However, precise analysis of data collected by the Cassini probe between 2004 and 2017 has allowed astronomers at the Paris Observatory, led by Valéry Lainey, to conclude that there is indeed an ocean 20 to 30 kilometers deep within Mimas.

This discovery is important for several reasons. Firstly, it demonstrates that oceans may be present in seemingly geologically inert places, meaning liquid water could be found on numerous bodies in the outer solar system.

Secondly, the presence of an ocean on Mimas suggests greater possibilities for the existence of extraterrestrial life, as where water interacts with the underlying rock, energy-carrying chemical reactions are generated that could be utilized by microorganisms.

Scientists believe that Mimas’ ocean formed recently, in the last 25 million years, as a result of internal heating caused by tidal forces exerted by Saturn and other nearby moons.

Over time, this ocean could end up fracturing Mimas’ icy surface, much like what happens on Enceladus, covering it with regenerated ice.

This discovery opens up new perspectives in the exploration of the solar system. If even a seemingly inert body like Mimas turns out to harbor an ocean, it’s possible that Uranian moons may exhibit the same phenomenon.

The boundaries of where water and life can exist in our planetary system are thus excitingly expanded.


Nature | Lainey, V., Rambaux, N., Tobie, G. et al. A recently formed ocean inside Saturn’s moon Mimas. Nature 626, 280–282 (2024).

  • Share this article:

Discover more from LBV Magazine English Edition

Subscribe to get the latest posts sent to your email.

Something went wrong. Please refresh the page and/or try again.