Interiors of the Giant Planets

Abstract

From our position as inhabitants of a rather insignificant rock orbiting close in to the Sun, there is an inevitable tendency to think of the giant planets (Jupiter, Saturn, Uranus, and Neptune) as being qualitatively similar. One of the major advances in our understanding of the giant planets in recent years has been the realization that this supposed similarity is superficial. With our previously blurred vision replaced by the focused spotlight of flyby spacecraft, and with recent theoretical and experimental advances in the properties of materials at high pressure, the individuality of these planets has emerged. Jupiter and Saturn, once thought to be very similar, now emerge as having substantially different compositions, evolutions, and structures. Uranus and Neptune still appear to be similar because our vision is still blurred (flybys not having taken place yet), but previous experience suggests that we should not be surprised if important differences exist.