According to research by French scientists, the cratered surface of Saturn's moon, Mimas (also known as Enceladus), may harbor an underground ocean. Analysis of data from the Cassini spacecraft suggests that this ocean is relatively young and still evolving. Further study of Enceladus could help us understand how this icy world formed. The findings were recently published in Nature.
Increasing evidence suggests that some moons may have oceans beneath their surfaces, but detecting these watery worlds is challenging. Enceladus, a small moon of Saturn, was considered an unlikely candidate due to its surface characteristics differing from other icy moons, such as Titan. Valery Lainey and colleagues from the Paris Observatory challenged this theory by evaluating observations of this small moon made by the Cassini spacecraft.
Previous studies proposed two possibilities for Enceladus's interior: an elongated rocky core or a global ocean. Lainey and colleagues' latest analysis revealed internal structures affecting its rotational motion and orbit. When applying solid models, a rocky core would need to be elongated into a thin disk, which contradicts observations. However, measurements of Enceladus's position suggest that its orbit is better explained by the influence of an internal ocean. The researchers calculated that this ocean lies approximately 20 to 30 kilometers beneath the icy shell and formed between 25 million to 2 million years ago. Hence, the signs of this subsurface ocean have yet to leave marks on the surface.
These findings indicate that processes occurring on Enceladus in recent times may be common during the early formation stages of other icy moons. "Lainey and colleagues' discovery will drive a comprehensive investigation of medium-sized icy moons across the entire solar system," noted Matija Cuk from the Search for Extraterrestrial Intelligence Institute and Alyssa Rose Rhoden from the Southwest Research Institute of Colorado in a concurrent news perspective article.
From Frédéric Durillon, Animea Studio, Paris Observatory
From Frederic Durillon, Animea Studio, Paris Observatory
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