Tethys is Saturn's fifth largest moon. Its irregular shape is 533 km in mean radius, with dimensions 1076.8 x 1057.4 x 1052.6 km. This cold, airless and heavily scarred body is very similar to sister moons Dione and Rhea except that Tethys is not as heavily cratered as the other two. This may be because its proximity to Saturn causes more tidal warming, and that warming kept Tethys partially molten longer, erasing or dulling more of the early terrain. Tethys' density is 0.97 times that of liquid water, which suggests that Tethys is composed almost entirely of water ice plus a small amount of rock.
urn:nasa:pds:context:target:satellite.saturn.tethys
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