This is a composite image of the small moons of Saturn.
Click on image for full size
NASA

The Composition of Small Moons

The small moons are so called because they are too small to see. That means it is hard to tell what they are made of.

What can be seen of them may suggest that they are made of rock because they are covered with craters as if they were very hard. When the Voyager missions flew by some the moons, however, they took measurements that showed that the inside is also made of ice. 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.

You might also be interested in:

Traveling Nitrogen Classroom Activity Kit

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

Voyager

Unexpected discoveries made by the two Voyager spacecrafts during their visits to the four largest planets in our solar system have changed the field of space science. Voyager 2 was launched on Aug. 2...more

Amalthea

Amalthea was discovered by E Barnard in 1872. Of the 17 moons it is the 3rd closest to Jupiter. Amalthea is about the size of a county or small state. Amalthea is named after the goat in Greek mythology...more

Callisto

Callisto was first discovered by Galileo in 1610. It is the 2nd largest moon in the solar system, and is larger than the Earth's moon. It is about as big as the distance across the United States. Callisto...more

Evolution of Callisto

Measurements by the Galileo spacecraft have been shown that Callisto is the same inside from the center to the surface. This means that Callisto does not have a core at the center. This means that, unlike...more

Very Large Impact Crater

Many different types of surface are shown in this picture. In the front is a huge crater, which goes for a long way over the surface. This crater could be compared to that of Mimas. They both show that...more

Surface of Callisto

The surface of Callisto is deeply marked with craters. Craters are the little white marks in the picture. It looks like it might be the most heavily cratered body in the whole solar system. And some of...more

Europa

Europa was first discovered by Galileo in 1610, making it one of the Galilean Satellites. It is Jupiter's 4th largest moon, 670,900 km ( miles) from Jupiter. Europa's diameter is about half the distance...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA