Chapter 12: Saturn

ancients

Saturn is the outermost planet known to the _______.

float

Saturn’s density is less than that of water, so it would ______ in a bathtub.

differential

Saturn rotates rapidly and exhibits _______ rotation.

flattest; rapid rotation and very low density

Saturn’s very large equatorial bulge makes it the _______ planet due to its __________.

Ring system

Saturn is best known for what spectacular feature?

rings

Saturn’s _____ lie in its equatorial plane

summer or winter

Ring are best seen during the peak of its ________.

fall and spring

Rings “disappear” during ______ because they are “edge on”.

92.4% molecular hydrogen and 7.4% helium (with traces of methane and ethane)

What is Saturn’s atmosphere primarily made up of?

gravity; temperatures

The abundance of hydrogen and helium in Saturn’s atmosphere is a result of strong ______ and low _______.

hold onto lighter gasses like helium and hydrogen

Saturn’s fairly high escape speed helps the planet ________.

helium

Saturn’s atmosphere has significantly less _______ than Jupiter’s.

It’s has thicker clouds (3 layers of 200 km) because Saturn’s gravity is less.

Why does Saturn have a more uniform appearance as compared to Jupiter?

Order of increasing depth (top to bottom): Ammonia, ammonium hydrosulfide, and water ice.

Describe Saturn’s thick cloud layers.

uniform appearance; convection and rapid rotation

Bands and storms do exist on Saturn, but are harder to see because of its more _______. What creates these features?

metallic hydrogen

Like Jupiter, Saturn has a layer of _________ within its interior, but its thinner.

Strong magnetic field

Saturn’s metallic hydrogen outer core results in a ________.

3x; internal hearing source

Saturn reradiates almost _____ times as much energy as it receives from the Sun, meaning it has a _______.

helium precipitation; helium

The source of Saturn’s internal heating is _________. This explains why there is less _____ in Saturn’s atmosphere than Jupiter’s.

having less metallic hydrogen

Saturn’s magnetosphere is only 5% as strong as Jupiter’s, probably due to __________.

moons

Saturn’s magnetosphere, which creates aurorae, does not encompass any of Saturn’s major ______, so its structure is different (i.e. there is not a plasma torus).

Galileo

_______ first saw Saturn’s rings in 1610 but did not know what he was looking at.

Christian Huygens

In 1655, __________ realized it was a system of rings.

Ice, dust, rock, and particles that range from fractions of millimeters to tens of meters; “dirty snowballs”

What are Saturn’s rings made of?

ringlets

Saturn’s rings are made up of _______, which are essentially density variations of ring particles formed from gravitational interactions between particles and moons.

When a large, low-density moon moved too close to the planet and experienced increasingly strong tidal forces. Once these forces became stronger than the moon’s own gravity, the moon broke apart, and its debris spread out to form rings.

How is Saturn believed to have formed its large system of rings?

The point where the tidal forces from the parent planet just begin to exceed the gravitational force holding the moon together.

What is the Roche Limit?

The Roche Limit only applies to moons or bodies that are large enough to be primarily held together by their own gravity.

Why are small moons (diameters of 10 km or less) able to survive within the Roche Limit?

Almost all the rings of Jovian planets fall within the parent planet’s Roche Limit with exceptions (E ring and G ring)

Do all of Saturn’s rings fall within Saturn’s Roche Limit?

Geysers and volcanic activity on the moon Enceladus which emits a lot of debris that contributes to the E ring; outside of Roche Limit

How is Saturn’s E ring maintained?

The particles from shepherd moons, which keeps particles between them by tugging on the particles equally in opposite directions; the F ring has a braided, kinked appearance.

How is Saturn’s F ring maintained?

Small moons that orbit near the outer edges of rings and the gravity of these moons keeps particles between them as they orbit.

What are shepherd moons?

50 million years

How old are Saturn’s rings believed to be?

146

How many moons are currently known to orbit Saturn?

Titan; 2nd

Saturn has on large moon, _____, which is the ____ largest moon in the Solar System.

It has a very thick atmosphere for its size; planets need gravity to have a high escape speed to prevent gases from escaping, but Titan lacked this.

Why were scientists so fascinated by Saturn’s large moon?

98% nitrogen and 2% methane with traces of other elements; hydrocarbons gave it a yellowish-orange color.

What is the atmosphere of Titan primarily made up of and what color does it appear to be?

Low temperatures that allow gases like methane to condense more easily.

How is Titan able to maintain such a thick atmosphere while the Galilean moons have none?

Rock/ice core, liquid water, ethane, and methane.

What is Titan mostly made up of?