Saturn’s moon Mimas – nicknamed the “Death Star” – could harbor an ocean inside. However, there are no signs of this on the surface.
San Antonio – The planet Saturn has 82 known moons and actually Mimas, the seventh largest of these moons, would only be one of many – if it were not for its special appearance: The crater Herschel with a diameter of 110 kilometers characterizes the exterior of the small moon, which itself has a diameter of just under 400 kilometers. The large crater gives the moon a look that at least “Star Wars” fans should be familiar with – even in professional circles it has the nickname “Death Star”.
But Mimas is not only interesting because of its appearance. As early as 2014, researchers suggested in a studythat there could be an ocean inside the small moon. At that time she had NASA-Mission* “Cassini”, which explored Saturn and its moons and crashed into Saturn in 2017*, a kind of wobble in the rotation of the moon around its planet. This phenomenon is often indicative of a geologically active body, within which there may also be an ocean. But on the surface, Mimas reveals nothing of this possible subsurface ocean. In complete contrast to Saturn’s moon Enceladus*, which emits clouds of steam and ice and is home to subterranean seas and presumably hot springs.
Saturn’s moon Mimas apparently harbors an underground ocean
“If Mimas has an ocean, it represents a new class of small, ‘cloaked’ ocean worlds with surfaces that don’t reveal the existence of the ocean,” said Alyssa Rhoden of the Southwest Research Institute in San Antonio, first author of a study of Saturn’s interior -Moon’s Mimas. The study was published in the journal Icarus.
In fact, celestial bodies with subterranean oceans are not uncommon in our solar system, as research over the past few decades has shown. Among other things, the subsurface oceans of the Jupiter moon Europa, the Saturn moons Titan and Enceladus and the dwarf planet Pluto are known. On the other hand, it is rather rare for a celestial body to have oceans on the surface – as we know it from Earth: In order for liquid water to be able to remain on the surface, the conditions have to be right – among other things, this is only in a certain area around the star possible, the so-called “habitable zone”. Subsurface oceans, on the other hand, also seem possible at greater distances from the star, as shown by the examples Europa, Titan, Enceladus and Pluto.
Underground ocean: Saturn’s moon Mimas “fooled” the researchers
Finding a possible ocean in Saturn’s moon Mimas came as a surprise to Rhoden, a specialist in the geophysics of ice satellites, particularly those containing oceans: “Since the surface of Mimas is cratered, we thought it might be it just a frozen block of ice,” says the researcher. “Worlds with an inner ocean like Enceladus and Europa tend to be fractured and show other signs of geological activity.” But the surface of Mimas “deceived the researchers and our new understanding has changed the definition of a potentially habitable world in our solar system and also significantly expanded,” explains Rhoden.
To find out if there might actually be a hidden ocean beneath the frozen surface of Mimas, the researchers created a model. With its help, they were able to study whether gravitational interactions with Saturn can create the tidal forces needed to heat the moon’s interior and keep the water beneath the icy shell warm enough to remain liquid. “When we create these models, we usually have to fine-tune them,” explains Rhoden. But this time, the indications of an underground ocean almost “jumped out at them”. According to the study, the ocean is under an ice sheet 22 to 32 kilometers thick.
mimas |
Saturn moon |
396.4 kilometers |
William Herschel |
17 Sep 178 |
Ice moon, large crater Herschel leads to the nickname Death Star |
Saturn moon Mimas: Number of possibly habitable worlds increases significantly
“Although our results suggest a present-day ocean in the interior of Mimas, it is difficult to reconcile the moon’s orbital and geological properties with our current understanding of its thermal-orbital evolution,” summarizes Rhoden and continues: “The Assessing Mimas as an ocean moon would challenge the models for its formation and evolution.”
Rhoden emphasizes that Mimas is an “interesting target for further investigations”. Finally, the possible subsurface ocean of Saturn’s moon greatly increases the number of possible habitable worlds in our galaxy. On celestial bodies where water exists in liquid form, there is always the possibility that life could exist. For this reason, researchers are also with the planet Mars* always on the Look for traces of water*.
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A planned flyby of the NASA space probe “Juno” to Jupiter’s moon Europa could help in the further exploration of Saturn’s moon Mimas in the future: “Juno” is to use a microwave radiometer to measure the heat flows of the Jupiter’s moon – data, which could also advance the exploration of Mimas. Europa is also expected to receive a visit from another spacecraft in the coming years. The NASA “Europa Clipper” mission is scheduled to start in 2024 and, above all, investigate the possible habitability of the Jupiter moon – here, too, there could be new findings that advance the research of Mimas. (Tanya Banner) *fr.de is an offer from IPPEN.MEDIA.
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