Shop Windows to the Universe

Our Glaciers: Then and Now activity kit helps you see the changes taking place in glaciers around the world. See all our activity kits and classroom activities.
This is a composite image of the small moons of Saturn.
Click on image for full size
NASA

Surface and Interior of Small Moons

The small moons are too small to be seen, so their structure can only be guessed. The surfaces seem to be covered with craters. There is probably a small core of some rocky material buried inside, and ice of various kinds over it.

Shop Windows to the Universe Science Store!

Our online store includes issues of NESTA's quarterly journal, The Earth Scientist, full of classroom activities on different topics in Earth and space science, ranging from seismology, rocks and minerals, oceanography, and Earth system science to astronomy!

Windows to the Universe Community

News

Opportunities

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

What Is a Mineral?

Minerals are the building blocks of rocks. There are many different types of minerals. All of them are solid and all are made of atoms of elements. Minerals can grow even though they are not alive. Most...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 by the National Science Foundation and NASA, our Founding Partners (the American Geophysical Union and American Geosciences Institute) as well as through Institutional, Contributing, and Affiliate Partners, individual memberships and generous donors. Thank you for your support! NASA AGU AGI NSF