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Science, Evolution, and Creationism, by the National Academies, focuses on teaching evolution in today's classrooms. Check out the other publications in our online store.
This is a cutaway of Ganymede's interior.
Click on image for full size
NASA

Interior of Ganymede

The diagram to the left shows a cutaway of the possible inside structure of Ganymede, based on recent measurements by the Galileo spacecraft. It shows a small core of metal, overlain with some rocky material, overlain still further with ice. Further measurements by Galileo suggest that, in addition, Ganymede may have a thin, salty-slushy layer near the surface, where electric currents are found. Ice cannot support electric current, but water can. (That is why people donít put electric appliances into the bathtub!)

When the Galileo spacecraft flew by Ganymede, to everyone's surprise it measured a very strong magnetic field for the first time near any moon! This provides further evidence that Ganymede is not completely frozen, but has a warm iron core.

Last modified September 19, 2003 by Jennifer Bergman.

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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