Saturn’s icy moon Mimas may be a “hidden” ocean world, according to new research.
Mimasthe smallest and innermost SaturnThe main moons are believed to generate enough heat to support a subsurface ocean of liquid water. Recent simulations of the moon’s Herschel Basin—the most striking feature on its hard crater surface—support the existence of a geologically young interior ocean surrounded by a thin ice sheet, along with its tectonic absence from Mimas. message (opens in new tab) from the Southwest Research Institute (SwRI) in San Antonio, Texas.
“NASA’s Waning Days Cassini During the Saturn mission, the spacecraft detected a strange libration, or wobble, in the rotation of Mimas, which often indicates a geologically active body that can support an internal ocean,” said Alyssa Roden, co-author of the new study and a SwRI scientist. , the statement said.
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However, despite this wobble, Mimas’ heavily cratered surface led scientists to initially view the moon as a frozen block of ice. This is because most of the ocean world is like geyser water Enceladus, one of Saturn’s other moons, is fractured and shows other signs of geological activity. However, there are no tectonic features in Mima.
“Mimas seemed an unlikely candidate, with its cold, hard cratered surface marked by one large crater that looked like a small moon. Death Star From “Star Wars,” Roden said in a statement. “If Mimas has an ocean, it represents a new class of small, ‘hidden’ ocean worlds with surfaces that don’t betray the presence of an ocean.”
When modeling the emergence of Herschel pool of influence, scientists determined that Mimas’ ice sheet must have been at least 34 miles (55 kilometers) thick at the time of impact. Meanwhile, observations of Mimas and models of its internal heating indicate that its current ice sheet is less than 19 miles (30 km) thick, according to the report.
These measurements show that the interior ocean has been moving and expanding since the basin formed. In addition, the researchers were only able to reconstruct the shape of the basin when they included the interior ocean in their models.
“We found that the Herschel ice crust could not have formed at its current thickness without destroying the ice rib,” said study lead author and postdoctoral researcher at the University of Arizona, Adin Denton. the statement said. “If Mimas has an ocean today, then the ice sheet has been thinning since Herschel’s formation, which could also explain the lack of cracks on Mimas. If Mimas is a new ocean world, this would place serious constraints on its formation, evolution, and habitability. In the middle of everything Moons of Saturn.”
These new models challenge scientists’ current understanding of thermal-orbital evolution, Roden said in a statement.
“Evaluating Mimas’ status as an oceanic moon will reveal patterns of its formation and evolution,” Roden said. “It helps us understand better The rings of Saturn and medium-sized moons, as well as the prevalence of habitable oceanic moons, particularly on Uranus. Mimas is an important target for further investigation.”
Their results were Posted on December 26, 2022 (opens in new tab)In Geophysical Research Letters.
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