Scientists Find Ocean Under Mimas, Less Than 25 Million Years Old
Updated
Updated · spacedaily.com · Aug 16
Scientists Find Ocean Under Mimas, Less Than 25 Million Years Old
2 articles · Updated · spacedaily.com · Aug 16
Summary
A global ocean beneath Saturn moon Mimas appears to sit under 20 to 30 kilometers of ice and to have formed less than 25 million years ago, making it strikingly young for an ocean world.
Cassini observations did not image water directly; researchers inferred the ocean by matching Mimas's rotational wobble and orbital periapsis drift, while a misshapen rocky-core model failed to explain both signals.
Mimas had long looked geologically dead — its 396-kilometer body is heavily cratered, including the 130-kilometer Herschel crater — but models suggest the ice shell thinned near the surface only 2 to 3 million years ago.
That recent thinning could explain why the moon lacks the fractures, plumes and resurfacing seen on Enceladus, even if tidal heating from a once more eccentric orbit had already started melting its interior.
The finding broadens the search for ocean worlds by showing that cratered, quiet moons can still hide liquid water, though Mimas's ocean chemistry, depth and habitability remain unknown.