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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.

The composition of the icy moons is mostly ice, therefore there is probably a small core of some rocky material buried inside, overlain with mantles of ice of various phases.

The diagram shows that there may be an ocean of water beneath the surface crust. This is because one of the phases of ice is water. 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 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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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