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Jump20of 100 · 1,280 M km from Earth

Mimas: the Death Star hides an ocean

Mimas looks like the Death Star, hides a newly formed ocean and its heat map draws a Pac-Man. Facts about this moon of Saturn, with sources.

Mimas, a grey moon full of craters with the huge crater Herschel on one side, photographed by Cassini
Image: NASA/JPL-Caltech/Space Science Institute · original

Curious facts

  1. It looks like the Death Star

    It is about 400 km across, and its crater Herschel, 130 km wide, spans a third of its diameter. NASA itself says the crater makes it look like the Death Star from Star Wars. 1

  2. A hidden and very young ocean

    In 2024 a study in Nature concluded that a global ocean lies under 20 to 30 km of ice. It is estimated to have formed only 5 to 15 million years ago: younger than the extinction of the dinosaurs, 66 million years ago (the comparison is mine). 23

  3. Its wobble gave it away

    Nobody expected it, because its surface shows no sign of activity. It was found by comparing Cassini data with the way Mimas wobbles in its orbit. 34

  4. A Pac-Man on its heat map

    In 2010 Cassini mapped its temperatures and found a Pac-Man shape: a warm region at about 92 K (−181 °C) and a cold one at about 77 K (−196 °C), with a sharp edge between them. JPL announced it as a video gamers’ paradise. 56

Mimas in Orbit

In the game, Mimas is jump 20 of the route, 1,280 M km from Earth. Its logbook card says:

Logbook · Jump 20

Its Herschel crater makes it look like the Death Star

I want to try Orbit Already in the group: download

Two steps with the Google account you use on Play: join the group, then download the test. Google Play can take a while, sometimes more than an hour, before it lets you download it; if you see “Item not found”, wait and try again.

What Orbit is like

Sources

  1. NASA, Mimas. science.nasa.gov/saturn/moons/mimas
  2. Lainey et al., Nature 626 (2024). doi.org/10.1038/s41586-023-06975-9
  3. IMCCE, Paris Observatory. imcce.fr/news/mimas-ocean
  4. Eos (AGU), 2024. eos.org/articles/thats-no-moon-its-an-ocean-world
  5. NASA Photojournal, PIA12867. science.nasa.gov/photojournal/bizarre-temperatures-on-mimas
  6. NASA JPL, 2010. jpl.nasa.gov/news/cassini-finds-a-video-gamers-paradise-at-saturn

Checked between 8 and 11 October 2026.

Image: NASA/JPL-Caltech/Space Science Institute · original