In Madrid, a remarkable discovery has been made. Beneath the surface of Mimas, one of the smallest moons of Saturn, lies a global ocean of liquid water. This surprising revelation, hidden beneath a cratered surface, was led by a team of researchers under Valéry Lainey, from the Paris Observatory-PSL. Their findings have been published in the renowned scientific journal, Nature.
The ocean is surprisingly young, estimated to have formed between 5 and 15 million years ago. This makes Mimas, the moon that bears resemblance to the Death Star from the Star Wars saga, an important target for studying the origins of life in our solar system.
Mimas is a small moon, only about 400 kilometers in diameter. Its cratered surface did not reveal the hidden ocean beneath, said Nick Cooper, co-author of the study and an honorary researcher at the Astronomy Unit of the School of Physical and Chemical Sciences at Queen Mary University of London.
Mimas now joins an exclusive club of moons with internal oceans, including Enceladus and Europa. However, Mimas stands out due to its ocean’s remarkably young age, estimated to be only 5 to 15 million years old.
Tidal interactions with the ringed planet
The ocean’s early age was determined through a detailed analysis of Mimas’s tidal interactions with Saturn. The analysis suggests that the ocean formed recently, based on the discovery of an unexpected irregularity in its orbit. As a result, it provides a unique window into the early stages of the formation of such seas and the potential for life to emerge.
The discovery was made possible by analyzing data from NASA’s spacecraft, Cassini. The spacecraft meticulously studied Saturn and its moons for more than a decade. By closely examining subtle changes in Mimas’ orbit, researchers were able to infer the presence of a hidden ocean and estimate its size and depth.
Cooper further added, “It has been a great team effort, with colleagues from five different institutions and three countries coming together under Lainey’s leadership to discover another fascinating and unexpected feature of the Saturn system, using data from the Cassini mission.”
The discovery of the young Mimas ocean has important implications for our understanding of the potential for life beyond Earth. It suggests that even small, seemingly inactive moons may harbor hidden oceans capable of supporting conditions essential for life, according to the authors of the study.