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Arches National Park Geology Tour provides an extensive, visually rich description of the geology of Arches, by Deborah Ragland, Ph.D. See our DVD collection.
This is a composite image of the small moons of Saturn.
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NASA

The Composition of Small Moons

What can be seen of the small moons may suggest a rocky composition because the surfaces seem to be covered with craters as if it were very hard. Composition is generally determined by detailed measurements of the spectra of an object. But most of the small moons are too small to be observed, so observations of this kind have yet to be made.

The Voyager spacecraft flew by some of the small moons of the Saturnian system and measured the density. The density of iron or rock is between 3 and 5. The density of ice is 1. Voyager measured the densities to be about 1.2 (refer to the reference information for exact measurements of the icy moons), which is closer to that of ice than rock, so most of these moons must be made out of ice, just as the icy moons are.

The fact that they are small and icy suggests a certain path for their evolution.


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