Jan 25, 2022 - Science

An ocean within Saturn's "Death Star moon"

Mimas looking like the Death Star. Photo: NASA/JPL/Space Science Institute

Mimas looking like the Death Star. Photo: NASA/JPL/Space Science Institute

Saturn's moon Mimas — which looks oddly like the Death Star from "Star Wars" fame — might be harboring an ocean beneath its crust.

Why it matters: Ocean worlds are thought to be some of the best places in the solar system — and beyond — to search for possible alien life.

What they found: Data from the final days of the Cassini mission studying Saturn and its moons revealed a tell-tale "oscillation" in the rotation of the moon that typically indicates an ocean within it, according to a new study in the journal Icarus.

  • Mimas, however, doesn't look like other worlds that likely harbor oceans beneath their crusts.
  • Worlds like Europa and Pluto tend to have surface features — like cracks and other geological markers — but Mimas doesn't outwardly appear to have any of those signs on the surface.
  • "If Mimas has an ocean, it represents a new class of small, 'stealth' ocean worlds with surfaces that do not betray the ocean’s existence," Alyssa Rhoden, one of the authors of the new study, said in a statement.
  • According to computer modeling done by the research team, Mimas appears to have a shell of ice 14–20 miles thick covering the ocean.

Yes, but: This new evidence may make scientists rethink what they understand of Mimas' evolution, possibly changing how they see other objects in the solar system as well.

  • If Mimas is an ocean world, it could help researchers learn more about whether other moons in the solar system, especially Uranus' moons, might have oceans within them, according to Rhoden.
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