Astronomers have uncovered a remarkable feature of one of Saturn’s smallest moons, Mimas, which is gaining attention for its potential uniqueness. Recent studies suggest that Mimas, renowned for its prominent Death Star-like crater, may conceal a vast ocean beneath its icy and pockmarked surface.
Published in the journal Nature, the study reveals that this hidden body of liquid water is relatively young, estimated to have formed only five to fifteen million years ago. The absence of obvious surface clues about the ocean’s existence raises the possibility that other seemingly barren moons might also possess hidden oceans, adding an intriguing dimension to the quest for extraterrestrial life.
Valéry Lainey, an astronomer from the Observatoire de Paris and co-author of the study, expressed the significance of the discovery, noting that if Mimas indeed harbors a global ocean, it suggests that liquid water could potentially exist in unexpected locations across celestial bodies.
Initially, Mimas appeared to offer little beyond its heavily cratered surface, composed primarily of a dense layer of water ice. However, closer examination, facilitated by NASA’s Cassini spacecraft starting in 2004, revealed subtle clues hinting at a more complex interior beneath the moon’s icy exterior.
Analysis of orbital and rotational data collected by Cassini indicated that Mimas experiences subtle gravitational fluctuations during its elliptical orbit around Saturn. These fluctuations, inconsistent with a solid interior, led researchers to propose the presence of a subsurface liquid ocean, trapped beneath an icy shell approximately 12 to 19 miles thick.
The researchers speculate that the ocean formed due to friction within Mimas’ rocky core induced by Saturn’s powerful tidal forces, gradually generating enough heat to melt portions of the surrounding ice shell.
Despite its intriguing properties, the ocean’s youth renders it highly improbable for supporting life. However, because Mimas is in the early stages of ocean formation, scientists see it as an opportunity to study the evolution of off-world seas and potentially identify conditions conducive to life.
Nick Cooper, co-author and astronomer at Queen Mary University of London, emphasizes Mimas’ significance as a subject for studying the origins of life due to the recently formed liquid water ocean.
Overall, Mimas serves as another example underscoring the prevalence of ocean-containing moons within our solar system, challenging previous assumptions about their abundance.
