Chapter 11 Jupiter

11.1 Orbital and Physical Properties

Mass: 1.9 × 10²⁷ kg ( twice as much as all other planets put together)
Radius: 71,500 km (112 times Earth’s)
Density: 1300kg/m— cannot be rocky or metallic as inner planets are
Rotation rate: Problematic, as Jupiter has no solid surface; different parts of atmosphere rotates at different rates
From magnetic field, rotation period is 9hr, 55 min

11.2 The Atmosphere of Jupiter

Major visible features:
- Bands of clouds; Great Red Spot
Great Red Spot has existed for at least 300 years, possibly much longer
Color and energy source still not understood
Atmosphere has bright zones and dark belts
Zones are cooler, and are higher than belts
Stable flow underlies zones and bands, called zonal flow
Composition of atmosphere: Mostly molecular hydrogen and helium; small amounts of methane, ammonia, and water vapor
These cannot account for color; probably due to complex chemical interactions

11.3 Internal Structure

No direct information is available about Jupiter’s interior but it's main components, hydrogen and helium, are quite well understood. The central portion is a rocky core.

11.4 Jupiter’s Magnetosphere

Jupiter is surrounded by belts of charged particles, much like the Van Allen belts but vastly larger.
Magnetosphere is 30 Million km across
Intrinsic field strength is 20,000 times that of Earth
Magnetosphere can extend beyond the orbit of Saturn

11.5 The Moons of Jupiter

63 moons have now been found orbiting Jupiter, but most are very small
The four largest are:
- Io, Europa, Ganymede, Callisto
Jupiter played invaluable role in sweeping solar system clear of debris before too much reached Earth —otherwise life might not have been possible
Europa has no craters; surface is water ice, possibly with liquid water below
Tidal forces stress and crack ice; water flows, keeping surface relatively flat

11.6 Jupiter’s Ring