Jovian Planets and Satellites

1. Jovian Planets and Satellites Realm of the Cold and Dark

2. Jovian vs. Terrestrial • Density: Jovian, 1 to 2; Terrestrial, 3 to 5 • Composition: Jovian, hydrogen + helium; Terrestrial, rocks + metals • State: Jovian, liquids + gases; Terrestrial, solids + plastics • Jovian larger than Terrestrial

3. Jovian vs. Terrestrial • Jovian more massive than Terrestrial • More internal energy at birth • Ratio mass/surface area less, lose energy at slower rate • Longer evolutionary lives, but no markers (solid surfaces)

4. Atmospheres • Upper layers visible; no distinct solid surfaces lower down • Thick: gases of hydrogen, helium, methane, ammonia • Weather driven by heat from interior (convection)

5. Interiors • Mantles: Density layers with gradual transitions; gases and liquids (lots of hydrogen) plus ices (methane, ammonia) • Cores: Rocky with some metals (earthlike); hot (few 10,000 K); temperature falls from center outward

6. Energy Outflow • Jupiter, Saturn, Neptune emit about twice as much energy as received from sun • Emit about 100 times that of the earth per square meter • Implies large store of internal heat (massive!)

7. Satellites (Lots!) • Most are mixtures of ices + rocks (density about 2) • Scant evidence of volcanism and tectonics on majority • Heavily cratered terrain about 4 Gy old, unevolved

8. Ring Systems • Small (baseball) to large (houses) sizes, independent orbits (Kepler’s laws) • Icy (bright) and carbon (dark) surfaces • In equatorial plane of planet • Result of tidal forces