Jupiter's moon Ganymede is not only the largest moon in the Solar System, it is larger than planets Mercury and Pluto. The robot spacecraft Galileo currently orbiting Jupiter has been able to zoom by Ganymede several times and snap many close-up pictures. Ganymede, shown above in its natural colors, sports a large oval dark region known as Galileo Regio. In general, the dark regions on Ganymede are heavily cratered, implying they are very old, while the light regions are younger and dominated by unusual grooves. The origin of the grooves is still under investigation.
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NASA Official: Jay Norris. Specific rights apply.
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& Michigan Tech. U.
Based on Astronomy Picture Of the Day
Publications with keywords: Jupiter - Moon - Ganymede - Solar System - Galilean Moon
Publications with words: Jupiter - Moon - Ganymede - Solar System - Galilean Moon