Jupiter has its own personal solar system in miniature of 63 known\nmoons. Most are tiny, irregular bodies that are a combination of\ncaptured asteroids and comets, but it is the 4 largest, the giant\nGalilean Moons: Io, Europa, Ganymede, and Callisto, that is of greatest\ninterest to us in this lecture. Each is a fascinating world of its own,\nwith a unique history and properties: volcanically active Io, icy Europa\nwhich may hide an ocean of liquid water beneath the surface, the grooved\nterrain of Ganymede, and frozen dirty Callisto with the most ancient\nsurface of the four. Recorded 2007 Nov 19 in 1000 McPherson Lab on the\nColumbus campus of The Ohio State University.