Simulations of the large Herschel crater determined that the basin structure and lack of tectonics in Mimas, Saturn’s smallest moon, is supported by a thinning ice sheet and a geologically young ocean. just below it, as published in the Geophysical Research Letters. This discovery would be a new class of “stealth” oceanic worlds and whose surfaces do not betray the presence of the ocean.
The finding was revealed by a team of researchers from the Southwest Research Institute of Texas (SwRI) in the United States.. In the final days of NASA’s Cassini mission to Saturn, the spacecraft identified a curious libration, or oscillation, in Mimas’s rotation, said Alyssa Rhoden, co-author of the new study and a SwRI scientist, in a statement that often points to a geologically active body capable of supporting an internal ocean.
What is pampering?
It is the smallest and innermost of Saturn’s major moons. Despite its barely 400 kilometers in diameter, its surface is full of craters of all sizes.although there is one that stands out powerfully from the others: Herschel crater (named after William Herschel, the astronomer who discovered Mimas in 1789).
The Herschel crater is 139 km in diameter and is precisely the one that received Mimas that appearance so similar to the famous “star of death” -the planet-destroying ship from the movie Star Wars.
“Mimas seemed an unlikely candidate, with its hard, icy surface cratered, scarred by a giant impact crater that makes the small moon look a lot like the Death Star from ‘Star Wars,'” Rhoden wrote. the notice. “If Mimas has an ocean, it represents a new class of small ‘stealth’ ocean worlds with surfaces that do not reveal the existence of the ocean.”
Curious release or suspicious oscillation
“Mimas seemed an unlikely candidate, with its hard, icy surface cratered, scarred by a giant impact crater that makes the small moon look a lot like the Death Star from ‘Star Wars'”Rhoden said in the statement published by the German network Deutsche Welle.
Rhoden found that the Mimas ice sheet, which today is no more than 30 km thick, must have been at least 55 km thick at the time of the collision. Which suggests that an internal ocean has been warming and expanding, at the cost of ice, since the very moment the basin formed. Furthermore, the researchers will only be able to recreate the shape of the basin when they have accounted for an inland ocean in their models.
“We discovered -says Adeene Denton, first author of the article- that Herschel could not have formed in an ice sheet with the true thickness without completely removing the ice sheet at the impact site. If Mimas has an ocean today, it means that the ice sheet has been thinning since the formation of Herschel, which could also explain the lack of fractures in Mimas. If Mimas is an emerging ocean world, that places significant constraints on the formation, evolution, and habitability of all of Saturn’s medium-sized moons.”
Rhoden believes that if there really is an ocean below the surface of Mimas, “it will be a challenge to reconcile the moon’s geological and orbital characteristics with our current understanding of its thermal orbital evolution. Considering Mimas as an oceanic moon would be a reference point for the models of its formation and evolution of these bodies. This would help us better understand Saturn’s rings and mid-size moons, as well as the prevalence of highly habitable oceanic moons, particularly Uranus. Mimas is a compelling target for further research.”
nt/ds
You may also like
