Figure 12-13: The Internal Structures of Jupiter and Satum These diagrams of the interiors of Jupiter and Saturn are drawn to the same scale. Each planet’s rocky core is surrounded by an outer core of liquid “ices,” a layer of helium and liquid metallic hydrogen, and a layer of helium and ordinary molecular hydrogen (H2). Saturn’s rocky core contains a larger fraction of the planet’s mass than does Jupiter’s, while Saturn has a smaller volume of liquid metallic hydrogen than does Jupiter.