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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 image shows stages in the evolution of Ganymede.

Evolution of Ganymede

The moons and planets formed by accretion of rocky material and volatiles out of the primitive solar nebula. As they finished forming, about 4 Billion Years ago, the surface continued to be bombarde d by the remmanent of planetary material available nearby. This period is called the Period of Late, Heavy Bombardment. From the Period of Late, Heavy Bombardment forward, this is probably what happened to Ganymede:

  • it warmed up from inside, which caused the inside to separate
  • the interior of Ganymede began to cool off
  • there was a late episode of further warming and volcanism, somewhat like case of Mars, which caused the surface to stretch and break, and which created the grooved terrain.

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This image shows an example of the grooved terrain of Ganymede. The image clearly shows that some things hit Ganymede and made craters after the grooves were made, because the grooves are underneath the...more

Evolution of Callisto

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Surface of Ganymede

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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