This is a cutaway of the possible interior of an icy moon.
Click on image for full size

Interior of Icy Moons

The diagram to the left shows a cutaway of the possible interior structure of an icy moon. The drawing illustrates what used to be postulated for Jupiter's moon Ganymede.

Icy moons are mostly made of ice, therefore there is probably a small core of some rocky material buried inside, covered with ice.

The diagram shows that there may be an ocean of water beneath the surface crust. If the temperature inside an icy moon is just right, then there might be water inside. Such an environment might prove to be habitable for life. For Jupiter's moon Europa, this scenario may prove to be very important.

The history of an icy moon involves cooling, however. So icy moons which may have had a water layer in the past might be completely frozen now.

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