Mimas measurements and ocean models. The amplitude of libration in longitude ϕs and variation of periapsis drift Δϖ for different models of internal structure with an ocean. The colors represent the thickness of the ice crust hs. The gray areas correspond to the measured libration amplitude and the perihelion longitude variation. The dispersion represents the sensitivity to polar and equatorial flattening of the crust (see additional tests in Methods). Credit: Nature (2024). DOI: 10.1038/s41586-023-06975-9
Hidden beneath the heavily cratered surface of Mimas, one of Saturn’s smallest moons hides a secret: a global ocean of liquid water. This astonishing discovery, led by Dr Valéry Lainey of the Paris-PSL Observatory and published in the journal Naturereveals a “young” ocean formed only 5 to 15 million years ago, making Mimas a prime target for studying the origins of life in our solar system.
“Mimas is a small moon, only about 400 kilometers across, and its heavily cratered surface left no trace of the ocean hidden beneath,” explains Dr Nick Cooper, co-author of the study and honorary researcher. at the astronomy unit. from the School of Physical and Chemical Sciences, Queen Mary University of London.
“This discovery adds Mimas to an exclusive club of moons with internal oceans, including Enceladus and Europa, but with a unique difference: its ocean is remarkably young, estimated to be only 5 to 15 million years old.”
This young age, determined through a detailed analysis of Mimas’s tidal interactions with Saturn, suggests that the ocean formed recently, following the discovery of an unexpected irregularity in its orbit. As a result, Mimas provides a unique window into the early stages of ocean formation and the potential for life to emerge.
“The existence of a recently formed ocean of liquid water makes Mimas a prime candidate for researchers studying the origin of life,” says Dr. Cooper. The discovery was made possible through analysis of data from NASA’s Cassini space probe, which has meticulously studied Saturn and its moons for more than a decade. By closely examining the subtle changes in Mimas’ orbit, researchers were able to infer the presence of a hidden ocean and estimate its size and depth.
Dr. Cooper continues: “This has been a tremendous team effort, with colleagues from five different institutions and three different countries coming together under the leadership of Dr. Valéry Lainey to discover another fascinating and unexpected feature of the Saturn system, in using data from the Saturn system. Mission Cassini.”
The discovery of the young Mimas Ocean has significant implications for understanding the potential for life beyond Earth. This suggests that even small, seemingly inactive moons may harbor hidden oceans capable of supporting conditions essential for life. This opens exciting new avenues for future exploration, potentially bringing us closer to answering the age-old question: are we alone in the universe?
More information:
Valery Lainey, A recently formed ocean inside Saturn’s moon Mimas, Nature (2024). DOI: 10.1038/s41586-023-06975-9. www.nature.com/articles/s41586-023-06975-9
Provided by Queen Mary, University of London
Quote: Mimas’ surprise: a small moon holds a young ocean under an icy shell (February 7, 2024) retrieved February 7, 2024 from
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