Chapter 8 Jovian Planet Systems...•Jovian planets all have rings because they possess many small moons close-in. •Impacts on these moons are random. •Saturn’s incredible rings
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Chapter 8Jovian Planet Systems
What are jovian planets made of?
Density Differences
0
0.5
1
1.5
2
Jupite
r
Satu
rn
Ura
nus
Nep
tune
Den
sity
(g
/cc
)
• Uranus and Neptuneare denser than Saturnbecause they have lessH/He, proportionately.
What are jovian planets like onthe inside?
Inside Jupiter• High pressure inside
of Jupiter causes thephase of hydrogento change withdepth.
• Hydrogen acts like ametal at great depthsbecause its electronsmove freely.
Jupiter’s Magnetosphere
• Jupiter’s strong magnetic field gives it an enormousmagnetosphere.
• Gases escaping Io feed the donut-shaped Io torus.
Aurora on Jupiter
What is the structure of Jupiter like?1. Rocky core, thin atmosphere2. Rocky core, thick atmosphere3. Gaseous on the outside, then liquid hydrogen,
more dense metallic hydrogen, rocky core4. Gaseous on the outside, then liquid hydrogen,
then helium, then the other elements
Jupiter does not have a large metalcore like the Earth. How can it have a
magnetic field?1. The magnetic field is left over from when
Jupiter accreted.2. Its magnetic field comes from the Sun.3. It has metallic hydrogen inside, which circulates
and makes a magnetic field.4. That’s why its magnetic field is weak.
What are Saturn’s rings like?
Earth-Based View
Spacecraft View of Ring Gaps
Artist’s Conception of Close-Up
Gap Moons• Some small moons
create gaps withinrings.
Jovian Ring Systems
• All four jovian planets have ring systems.• Others have smaller, darker ring particles than does Saturn.
Why do the jovian planets haverings?
• They formed from dust created in impactson moons orbiting those planets.
How do we know this?
How do we know?
• Rings aren’t leftover from planet formationbecause the particles are too small to havesurvived this long.
• There must be a continuous replacement oftiny particles.
• The most likely source is impacts with thejovian moons.
Ring Formation
• Jovian planets all have rings because theypossess many small moons close-in.
• Impacts on these moons are random.• Saturn’s incredible rings may be an “accident”
of our time.
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