In a groundbreaking discovery, astronomers have uncovered compelling evidence of a vast ocean hiding beneath the icy surface of Mimas, one of Saturn's moons. With its resemblance to the Death Star from the iconic “Star Wars” series, Mimas is an intriguing celestial body that has long captured the attention of scientists. Led by a team of French researchers, the study utilized data from NASA's Cassini spacecraft, which spent over a decade observing Saturn and its extensive moon system before its final descent into the planet's atmosphere in 2017.

The team's analysis of Mimas' orbit and rotation revealed that a hidden ocean, estimated to be located 12 to 18 miles (20 to 30 kilometers) beneath the frozen crust, is more likely than a rocky core. This discovery challenges previous assumptions about the moon's composition and raises the possibility of Mimas being a potential habitable world. Co-author Valery Lainey from the Paris Observatory expressed surprise at the findings, stating that Mimas was an unlikely candidate for hosting a global ocean or liquid water.

Unlike other moons in the Saturnian and Jovian systems, such as Enceladus and Europa, Mimas lacks visible signs of subsurface activity such as fractures and geysers. However, further examination of the moon's features revealed its remarkable characteristics. Measuring a mere 250 miles (400 kilometers) in diameter, Mimas is heavily cratered and boasts the second largest impact crater among all moons in the solar system, hence its comparison to the fictional Death Star.

The ocean beneath Mimas' icy exterior is estimated to occupy half of the moon's volume. However, due to its small size, it represents only a fraction, approximately 1.2% to 1.4%, of Earth's oceans. Despite its diminutive stature, Mimas holds immense scientific value. According to co-author Nick Cooper from Queen Mary University of London, the presence of a "remarkably young" liquid water ocean positions Mimas as an ideal candidate for studying the origins of life.

The age of the subterranean ocean is estimated to be between 5 million and 15 million years, making it too young to leave visible marks on the moon's surface. Lainey suggests that the overall temperature of the ocean is likely to be around freezing. However, he speculates that the water temperature at the seafloor could be considerably warmer, potentially creating an environment conducive to the development of life.

The findings, which have been published in the journal Nature, have garnered significant attention within the scientific community. In an accompanying editorial, Matija Cuk from the SETI Institute and Alyssa Rose Rhoden from the Southwest Research Institute expressed their excitement over the discovery, highlighting the inspiration provided by the idea that small, icy moons can harbor young oceans.

Mimas, discovered by English astronomer William Herschel in 1789, derives its name from a giant in Greek mythology. This recent revelation about the moon's hidden ocean adds to its enigmatic allure. As scientists continue to unravel the mysteries of our solar system, Mimas stands as a testament to the wonders that lie beyond our own planet.

The research conducted by the French-led team, supported by NASA's Cassini spacecraft, opens up new possibilities for understanding the potential habitability of celestial bodies and the origins of life. As our knowledge of the universe expands, the significance of seemingly insignificant moons like Mimas becomes increasingly apparent. The Associated Press Health and Science Department, with support from the Howard Hughes Medical Institute's Science and Educational Media Group, is dedicated to delivering groundbreaking scientific news to the public.