Key facts
- Scale fact
- 396 kmdiameter
- Estimated age
- ~4.5 billion years
- Composition
- Mostly water ice
- Temperature
- ~75 K surface
Mimas
396 kmdiameter
Visual creditCassini 2010 / NASA / JPL-Caltech / Space Science Institute / Public domainSource: Wikimedia Commons
Details
Mimas is a small, heavily cratered moon of Saturn whose icy shell is dominated by the 130-kilometer Herschel crater. A 2024 analysis of its orbital motion found evidence for a young global ocean 20–30 kilometers beneath that old-looking surface.
Herschel crater spans about one third of Mimas’s diameter. The impact may have approached the energy needed to disrupt the moon, but the cratered exterior otherwise shows little of the fractures or resurfacing associated with better-known ocean moons.
A 2024 study used Cassini measurements of Mimas’s orbital precession to infer a global ocean beneath an ice shell 20–30 kilometers thick. The authors’ thermal and orbital models indicate that the ocean formed recently on geological timescales. It is an inference from the moon’s motion rather than a direct detection of liquid water.
Links
- Universe journey
- Asteroid belt & Jupiter
- Wikipedia
- Mimas on Wikipedia
Size neighbors
Objects near Mimas on the scale
Sources
References for Mimas
Measurements and descriptive context are compiled by the Scale of Space team from the references below. If you find an error, please let us know.
- Mimas — Wikipedia
- Visual reference: Wikimedia Commons (Cassini 2010 / NASA / JPL-Caltech / Space Science Institute, Public domain)
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Scale of Space is a scroll-based journey through the universe, placing objects on a single logarithmic scale so you can compare size across an unbroken range.
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