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- Tethys on Wikipedia
Tethys
Details
Tethys is a bright icy moon of Saturn, marked by the huge Odysseus crater and a great valley system called Ithaca Chasma. Its low density and high reflectivity point to a body made mostly of water ice.
Tethys matters because it looks like a small, bright ice world that has been written on by impacts at almost absurd scale. It is one of Saturn's mid-sized moons, cold and airless, but its surface is not visually anonymous. The giant Odysseus crater is so large relative to the moon that it turns Tethys into a lesson in how close an impact can come to defining an entire body.
The other signature is Ithaca Chasma, a long valley system that gives Tethys a second large-scale scar. NASA describes Tethys as similar to Dione and Rhea in broad character, but less heavily cratered, possibly because tidal warming kept it partially molten longer and softened some early terrain. That makes the moon feel less like a static ice ball and more like a body whose surface remembers both impacts and internal response.
That is why Tethys belongs on this scale. Its importance is not just that it is about a thousand kilometers across, but that a small icy moon can preserve planet-sized drama in miniature: a mostly water-ice body, an enormous impact basin, and a valley system that makes its frozen surface read as a history of stress.
466km
Key facts
- Scale fact
- 1,066 kmmean diameter
- Composition
- Mostly water ice with a small amount of rock
- Temperature
- ~86 K average surface
Scale context
Where Tethys sits on the full axis
Shared physical scale
895km
Together, these objects make the size change around Tethys easy to compare at a glance.
Sources
References for Tethys
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.
- Tethys — Wikipedia
- Visual reference: Wikimedia Commons (NASA / JPL-Caltech / SSI / Gordan Ugarkovic, Public domain)
Between the smallest and the largest, perspective is everything.
About
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.
Guides turn parts of that scale into curated essays, while focused views let you explore the same range through specific groups of objects.