1. The Jovian Planets

2. The Jovian, or gaseous, planets have rocky cores surrounded by thick atmospheres. The radius is measured to the point at which the pressure drops to 1 atmosphere.

3. The Voyager Mission

4. Jupiter Diameter11 D E Rotation Period 10 hours Orbital Period 12 years Distance from Sun5.203AU Orbit Eccentricity 0.05 Tilt 3 degrees Temperature-120C Atmospherehydrogen, helium, ammonia and methane Gravity2.34g Moons>39 VisitsPioneer 10 & 11, Voyager 1 & 2, Galileo, Cassini

5. Voyager 1

6. The Galilean Moons Io Europa Ganymede Callisto 5260 km 4800 km 3140 km 3630 km

7. The Galileo Probe Launched by space shuttle in 1989 Gravity assists with the Venus and the Earth Observed asteroid Ida, SL9 impact on Jupiter Arrived at Jupiter in December 1995 Dropped probe into Jupiter's atmosphere Orbited the Galilean moons until 2003

8. Io Being the closest moon to Jupiter, Io's core is heated by Jupiter's tidal forces, creating large-scale volcanic activity that coats the moon's surface with yellow sulfur.

9. Io has a young surface, with no impact craters, which is constantly being renewed

11. Shoemaker-Levy 9 Impact Upon Jupiter