PHY 113 Lecture Notes - Lecture 12: The Moons, Thunderstorm, Gravitational Field
9 Jun 2018
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Chapter 12 Saturn
12.1 Orbital and Physical Properties
12.2 Saturn’s Atmosphere
12.3 Saturn’s Interior and Magnetosphere 12.4 Saturn’s Spectacular Ring System 12.5
The Moons of Saturn
Dancing Among Saturn’s Moons
12.1 Orbital and Physical Properties
Radius: 60,000 km (~10 times Earth)
water!
Rotation: Rapid and differential, enough to flatten Saturn considerably
Rings: Very prominent; wide but extremely thin
View of rings from Earth changes as Saturn orbits the Sun.
Rings are in Saturn’s rotational plane
most tilted during Saturn’s summer and winter
Edge-on during Saturn’s spring/fall (equinoxes)
12.2 Saturn’s Atmosphere
Saturn’s atmosphere also shows zone and band structure (similar to Jupiter), but coloration is
much more subtle, because Saturn’s atmosphere is much thicker (harder to see “through” the
top layers)
Mostly molecular hydrogen, helium, methane, and ammonia; helium fraction is much less
than on Jupiter
This true-color image shows the delicate coloration of the cloud patterns on Saturn
pressure is lower Three cloud layers
Cloud layers are thicker than Jupiter’s; see only top layer
Structure in Saturn’s clouds can be seen more clearly in this false-color image, including
storms
Wind patterns on Saturn are similar to those on Jupiter, with zonal flow and differential
rotation
Jupiter-style “spots” rare on Saturn; don’t form often and quickly dissipate if they do
This image shows what is thought to be a vast thunderstorm on Saturn, as well as the polar
vortex at Saturn’s south pole.
12.3 Saturn’s Interior and Magnetosphere
Interior structure similar to Jupiter’s
Saturn also radiates roughly 3 times more energy than it gets from the Sun, but not because of
cooling. (This is even more relative radiation than Jupiter gives off!)
Where does this energy come from?
• Helium and hydrogen are not well mixed; helium tends to
condense into droplets and then fall
• Gravitational field compresses helium and heats it up
• As Jupiter continues to cool, a similar process will probably happen there, causing it to give
off more energy than it does now!
Saturn also has a strong magnetic field, but only 5% as strong as Jupiter’s
Creates aurorae similar to Jupiter (and Earth)
12.4 Saturn’s Spectacular Ring System
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
12. 3 saturn"s interior and magnetosphere 12. 4 saturn"s spectacular ring system 12. 5. Rotation: rapid and differential, enough to flatten saturn considerably. View of rings from earth changes as saturn orbits the sun. Rings are in saturn"s rotational plane most tilted during saturn"s summer and winter. Saturn"s atmosphere also shows zone and band structure (similar to jupiter), but coloration is much more subtle, because saturn"s atmosphere is much thicker (harder to see through the top layers) Mostly molecular hydrogen, helium, methane, and ammonia; helium fraction is much less than on jupiter. This true-color image shows the delicate coloration of the cloud patterns on saturn pressure is lower three cloud layers. Cloud layers are thicker than jupiter"s; see only top layer. Structure in saturn"s clouds can be seen more clearly in this false-color image, including storms. Wind patterns on saturn are similar to those on jupiter, with zonal flow and differential rotation.
