This is a cutaway of the interior of Ganymede.
Click on image for full size
Image from: The New Solar System
Evolution of the Interior of Icy Moons
Ice can restucture itself into many different forms. The forms are called
phases. Phases can be as different as diamond and graphite. As can be seen in these pictures,
diamond has a very different size and shape than does that of
graphite.
The "phase" of ice plays a very important role in the evolution of the icy satellites. As the temperature rises or falls inside the moon, the ice inside will restructure itself and change shape. Thus the moon itself will change its shape as the moon evolves!
The movie shows how the satellite might evolve as it cools and the ice inside changes form. Some layers within the satellite may entirely disappear, and the satellite itself may change in size because some ice phases take less space than others! Part of the movie shows the water ice phase diagram.
You might also be interested in:

If the satellite has means of warming itself, then beside surface changes due to evolution, then the interior may go through many startling changes as the moon evolves. The moon may have water inside,
...more
If the satellite has means of warming itself, then the interior may go through many startling changes as the moon evolves. The moon may change its size, and grow or shrink as the layers inside go through
...more
Amalthea was discovered by E Barnard in 1872. Of the 17 moons it is the 3rd closest to Jupiter, with a standoff distance of 181,300 km. Amalthea is about the size of a county or small state, and is just
...more
Callisto was first discovered by Galileo in 1610, making it one of the Galilean Satellites. Of the 60 moons it is the 8th closest to Jupiter, with a standoff distance of 1,070,000 km. It is the 2nd largest
...more
Most of the moons and planets formed by accretion of rocky material and volatiles out of the primitive solar nebula and soon thereafter they differentiated. Measurements by the Galileo spacecraft have
...more
Many examples of the differing types of terrain are shown in this image. In the foreground is a huge impact crater, which extends for almost an entire hemisphere on the surface. This crater may be compared
...more
The surface of Callisto is deeply pockmarked with craters. It looks to be perhaps the most severely cratered body in the solar system. There are also very large craters to be found there. The severity
...more