The roster of celestial bodies in our Solar System harboring oceans continues to expand, with Saturn’s moon Mimas now joining the exclusive club. A recent paper published in Nature presents compelling evidence pointing to a subsurface ocean beneath Mimas’s cratered surface. This revelation challenges initial assumptions about the moon’s geological history.
Mimas, the smallest of Saturn’s seven major moons, completes an orbit in less than a day and is renowned for hosting the second-largest crater in the Solar System—Herschel Crater, which gives the moon an uncanny resemblance to the Death Star. The heavily cratered surface led scientists to believe that Mimas had been relatively static throughout its history, unlike moons such as Europa and Enceladus with more dynamic surfaces due to subsurface oceans.
However, anomalies in Mimas’s rotation, observed during the Cassini mission, hinted at a possible subsurface ocean. While the irregularities could be attributed to an uneven rocky core, researchers in 2022 calculated tidal forces’ energy on Mimas, suggesting it could generate enough heat to form a subsurface ocean.
The latest study, conducted by European scientists using Cassini data, focused on Mimas’s orbital mechanics. The moon’s elliptical orbit experiences shifts in its long axis over time due to gravitational forces from Saturn and other moons. A rocky core with an unusual shape could explain these orbital changes, but reconciling both orbital and rotational wobbles necessitates a core shaped like an extremely oblong, pancake-shaped disk—inconsistent with observations. The more plausible explanation is the presence of a subsurface ocean.
Calculations projecting Mimas’s history revealed that the ocean likely formed within the last 25 million years, possibly as recent as 3 million years ago. The lack of surface evidence for the ocean could be attributed to its recent formation. Interactions with other moons or influences from Saturn’s rings, if formed relatively recently, might have triggered the ocean’s emergence.
While uncertainties remain, astronomers are now motivated to explore further and gather data that could unravel the mysteries surrounding Mimas’s subsurface ocean. This discovery adds a new layer of complexity to our understanding of Saturn’s moons and reinforces the need for continued exploration and observation.
Conclusion :
Mimas’s potential subsurface ocean challenges assumptions, sparking scientific intrigue and underscoring the importance of ongoing space exploration.