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This drawing shows the evolution of Callisto.
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NASA

Evolution of Callisto

Most of the moons and planets formed by accretion of rocky material and volatiles out of the primitive solar nebula and soon thereafter they differentiated.

Measurements by the Galileo spacecraft have been shown that Callisto is completely homogeneous inside, and never differentiated. This means that, unlike Ganymede, Callisto probably never warmed inside enough to allow for the materials to separate. Planets gain heat by many means. The fact that Callisto never warmed could mean one of many things:

The lack of warmth prevented any movements of the crust which would have changed the appearance of the surface over time.

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Traveling Nitrogen Classroom Activity Kit

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

Differentiation

Differentiation is a scientific term which really means "to separate". In their earliest history, elements which comprised the planets and moons would part into separate regions, if the body was warm enough....more

Tidal Forces

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Surface of Callisto

The surface of Callisto is deeply pockmarked with craters. It looks to be perhaps the most severely cratered body in the solar system. There are also very large craters to be found there. The severity...more

Amalthea

Amalthea was discovered by E Barnard in 1872. Of the 17 moons it is the 3rd closest to Jupiter, with a standoff distance of 181,300 km. Amalthea is about the size of a county or small state, and is just...more

Callisto

Callisto was first discovered by Galileo in 1610, making it one of the Galilean Satellites. Of the 60 moons it is the 8th closest to Jupiter, with a standoff distance of 1,070,000 km. It is the 2nd largest...more

Evolution of Callisto

Most of the moons and planets formed by accretion of rocky material and volatiles out of the primitive solar nebula and soon thereafter they differentiated. Measurements by the Galileo spacecraft have...more

Very Large Impact Crater

Many examples of the differing types of terrain are shown in this image. In the foreground is a huge impact crater, which extends for almost an entire hemisphere on the surface. This crater may be compared...more

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