Exploratour - Evolution of the Solar System
This is a cutaway drawing of the proposed structure of Ganymede's interior.
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NASA
Click on image for full size
NASA
Differentiation is a scientific term which really means "to separate into layers". Planetary elements which separate include the heavy iron and the lighter silicate rock. Iron falls to the center of a planet and forms a core, silicate material might forms a mantle on top of the core.
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