1. Helium rain lower temperatures of Saturn's interior allow helium to come out of solution with...
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Transcript of 1. Helium rain lower temperatures of Saturn's interior allow helium to come out of solution with...
1. Helium rain
• lower temperatures of Saturn's interior allow helium to come out of solution with hydrogen and form droplets, these droplets fall toward the center of Saturn depleting the outer layers of helium and producing the excess heat that is radiated by Saturn.
2. Tidal stability limit
• the distance from a planet within which a moon will be torn apart by the gravitational pull, believed to be the cause of the rings of the Jovian planets, also called the Roche limit.
3. Roche limit
• --the distance from a planet within which a moon will be torn apart by the gravitational pull, believed to be the cause of the rings of the Jovian planets, also called the tidal stability limit.
4. ringlets
• smaller rings that actually make the ring structure of Saturn, discovered by the Voyager spacecraft, numbering in the tens of thousands.
6. moonlets
• small moons that scoop up ring material as the moon moves through its orbit leaving a gap in its wake
7. resonance
• repeated gravitational pull in certain areas of the ring by small moons (Mimas, for example) that produces gaps in the rings
8. shepherd satellites
• -the two small moons which keep the F-ring in place, Prometheus and Pandora
9. spokes
• dark lines extending outward through the rings, caused by small particles suspended above the plane of the rings
15. coorbital satellites
• Janus and Epimethius, have the same orbit, one slightly closer to Saturn than the other; every 4 Earth years they switch places
16. LaGrange points
• points where smaller moons accompany larger moons in their orbits, 60 degree angles to the larger moon
17. chaotic rotation
• orbit of Hyperion, because of gravitational pull of Saturn and Titan the orbit is not circular; moon constantly changes rotational speed and and axis
1. Why is Saturn's polar radius shorter than its equatorial radius?• Saturn has a low density and a high rotation
rate. This causes Saturn to be flattened. The term for this is oblateness.
2. Which two elements make up most of Saturn? How does this compare to Jupiter?• Hydrogen and Helium, same as Jupiter.
3. Why is Saturn's surface appearance so much more uniform than Jupiter's?
• Saturn's weaker gravity results in a thicker atmosphere, so holes in the upper atmosphere don't show the lower darker layers as on Jupiter.
5. What is the tidal stability limit (Roche limit)?• The distance from a planet within which a
moon will be torn apart by the gravitational pull of the planet.
6. List two ways Saturn's moons affect Saturn's rings.• Some moons sweep through the rings
plowing out gaps. Other moons produce gaps due to gravitational pull on the rings.
7. What are shepherd satellites?
• Two moons (Prometheus and Pandora) that form the "braided" F-ring.
11. What is unique about the orbits of Hyperion and Phoebe?• Hyperion has a chaotic orbit because of
Titan's gravity, constantly changing its rotation speed and axis.
• Phoebe is Saturn's only moon with a retrograde orbit.