* Jupiter and Saturn have much larger diameters and are much more massive than the other planets in the solar system. Their densities, however, are lower than the terrestrial planets. This implies that Jupiter and Saturn are made up primarily of the light elements, hydrogen and helium.
* The parts of Jupiter and Saturn that we can see are atmospheric
clouds. For both planets, rotation period varies with latitude,
producing a system of zonal winds similar to the Earth's jet stream.
* Jupiter and Saturn have tropospheres in which pressure and temperature
decrease steadily with altitude. The atmospheres of Jupiter and
Saturn are made primarily of hydrogen and helium.
* Jupiter shows many cloud features. One of these, the Great Red
Spot, is an atmospheric storm that has persisted for centuries.
Other features, such as white ovals, last for decades. Saturn
also shows many cloud features, but not as many as Jupiter.
* The clouds of Jupiter and Saturn are separated into several
decks with clear regions in between. They consist primarily of
ammonia, ammonium hydrosulfide, and water, all of which are colorless.
The compounds that color the clouds brown, blue, red, and orange
have not yet been identified.
* The dark cloud features of Jupiter and Saturn are warmer and
lie deeper in the atmosphere than the light cloud features. The
Great Red Spot is an exception, however. It is one of the coldest,
highest atmospheric features on the planet.
* In the atmospheres of Jupiter and Saturn, hydrogen exists as
a molecular gas. Beneath the atmospheres, however, as the pressure
increases, hydrogen gradually turns into a liquid. Even deeper
within each planet, hydrogen changes abruptly to a metallic liquid.
* Both Jupiter and Saturn are too dense to be made entirely of
hydrogen and helium. They must contain other, heavier materials,
such as rock, ice, and metal. It is likely that the heavy materials
form the cores of Jupiter and Saturn.
* Both Jupiter and Saturn are self-luminous. For each planet,
one half or more of the energy emitted is derived from internal
sources.
* Just after it formed Jupiter was much larger than it is now.
While it contracted to its present size, Jupiter converted large
amounts of gravitational energy into heat. For a brief time during
its early contraction, it was almost 1% as luminous as the Sun.
Today Jupiter's luminosity is derived from energy stored from
the time when it was contracting rapidly. Although Saturn also
converted gravitational energy into heat as it formed, most of
the planet's present internal energy has a different origin. Possibly
it is due to the separation of hydrogen and helium within Saturn.
* Jupiter and Saturn have large magnetic fields and enormous magnetospheres.
In fact, Jupiter's magnetotail extends beyond the orbit of Saturn.
* The rings of Jupiter and Saturn consist of many individually
orbiting particles. Collisions among the particles have gradually
brought all of the particle orbits into the same plane. Thus the
rings are extremely thin compared with their diameters.
* The rings of Saturn consist of many individual ringlets separated
by gaps. Some of the gaps are caused by the gravitational influences
of Saturn's satellites.
* Spokes, dark radial features in Saturn's rings, may be the shadows
of minute particles that have been lifted above the rings by electromagnetic
forces.
* Most of the material in planetary rings lies inside the Roche
distance, the distance from the planet within which bodies are
destroyed by tidal forces. Planetary rings were probably formed
relatively recently by the destruction of a body, perhaps a satellite,
which ventured inside the planet's Roche distance.
Cassini's division, equatorial jet, Great Red Spot, metallic hydrogen,resonances, Roche distance, spokes,zonal winds
1. What element is Jupiter primarily made of? hydrogen
2. The equatorial diameter of Jupiter is about 6% larger than
the polar diameter of Jupiter. Why? Jupiter rotates rapidly
3. How do we know that the dark colored regions in the atmosphere
of Jupiter are generally hotter than the light colored regions?
they emit more infrared radiation than the light regions
4. If there is any rocky material in Jupiter and Saturn, where
is it likely to be located? in the cores of the planets
5. The amount of infrared energy emitted by Jupiter is about twice
as great as the amount of sunlight which the planet absorbs. What
is the significance of this discrepancy? it implies that there
are significant energy sources within Jupiter
6. Which of the following best describes the evolution of Jupiter
since soon after it formed? it has grown steadily dimmer and cooler
7. The radio emission originating from Jupiter at short-wave radio
frequencies is thought to be caused by:Interaction of the satellite
Io with the Jovian magnetosphere
8. How does Saturn compare to Jupiter? it is less massive and
has less colorful clouds
9. How do we know that the rings of Saturn are made of independently
orbiting particles rather than solid sheets of material? the inner
and outer edges of the rings have different orbital periods
10. What is the Roche limit? the distance from a planet at which
tides would destroy a satellite