astronomy chapter 8

Which of the following is NOT a general characteristic of the four jovian planets in our solar system?

They are higher in average density than are the terrestrial planets.

Which of the following best describes the internal layering of Jupiter, from the center outward?

core of rock, metal, and hydrogen compounds thick layer of metallic hydrogen thick layer of liquid hydrogen layer of gaseous hydrogen cloud layer

Which of the following statements comparing the Jovian interiors is NOT thought to be true?

they all have the same exact set of internal layers, though these layers differ in size

Overall, Jupiter’s composition is most like that of _________.

the sun

Jupiter’s colors come in part from its three layers of clouds. Which of the following is NOT the primary constituent of one of Jupiter’s cloud layers?

clouds of sulfuric acid

How do typical wind speeds in Jupiter’s atmosphere compare to typical wind speeds on Earth?

They are much faster than hurricane winds on Earth.

What is the Great Red Spot?

a long lived, high pressure storm on Jupiter

What atmposheric constituent is responsible for the blue color of Uranus and Neptune?

Methane

How does the strength of Jupiter’s magnetic field compare to that of Earth’s magnetic field?

Jupiter’s magnetic field is about 20,000 times as strong as Earth’s.

Which of the following statements about the moons of the Jovian planets is NOT true?

most of the moons are large enough to be spherical in shape, but a few have the more potato like shapes of asteroids

Which statement about Io is true?

Io is the most volcanically active body in our solar system.

Which moon has a thick atmosphere made mostly of nitrogen?

Titan

The Hugyens probe took numerous pictures as it descended to Titan’s surface in 2005. What did the pictures show?

features of erosion, including what appeared to be dry river valleys and lakebeds

Which large Jovian moon is thought to have been captured into its present orbit?

Triton

Which moon is considered likely to have a deep, subsurface ocean of liquid water?

Europa

Suppose you could float in space just a few meters above Saturn’s rings. What would you see as you looked down on the rings?

countless icy particles, ranging in size from dust grains to large boulders.

Which statement about planetary rings is NOT true?

Saturn’s rings formed along with its moons 4.6 billion years ago.

Which of the following gases is NOT a significant ingredient of the jovian planet atmospheres?

carbon dioxide

Jupiter and the other jovian planets are sometimes called "gas giants." In what sense in this term misleading?

They actually contain relatively little material in a gaseous state.

What would happen to Jupiter if we could somehow double its mass?

Its density would increase but its diameter would barely change

According to our theory of solar system formation, why did Uranus and Neptune end up to be much less massive than Jupiter and Saturn?

Particles in the solar nebula were more spread out at greater distances, so that accretion took longer and there was less time to pull in gas before the solar wind cleared the nebula.

Why does Jupiter have three distinct layers of clouds?

The three layers represent clouds made of gases that condense at different temperatures.

Which of the following best explains why we see horizontal stripes in photographs of Jupiter and Saturn?

The light stripes are regions of high clouds, and the dark stripes are regions where we can see down to deeper, darker clouds

Uranus and Neptune have methane clouds but Jupiter and Saturn do not. Which factor explains why?

Temperatures on Jupiter and Saturn are much too high for methane to condense

Which Jovian planet has the most extreme seasonal changes?

Uranus

Why is the radiation so intense in the region that traces Io’s orbit around Jupiter?

The region is full of gases that become ionized after they are released from volcanoes on Io.

Which of the following best explains why many Jovian moons have been more geologically active than the moon or mercury?

Jovian moons are made mostly of ice that can melt or deform at lower temperatures that can the rock and metal that make up the Moon or Mercury.

All of the following statements are true. Which one is most important in explaining the tremendous tidal heating that occurs on Io?

Io orbits Jupiter on an elliptical orbit, due to orbital resonances with other satellites.

Which of the following is NOT a piece of evidence supporting the idea that Europa may have a subsurface ocean?

Astronomers have detected small lakes of liquid water on Europa’s surface.

Which of the following is most unlikely to be found on Titan?

lakes of liquid water in the warmer equatorial regions

Why do astronomers believe that Triton is a captured moon?

Triton orbits Neptune in a direction opposite that of Neptune’s rotation

Which statement about Saturn’s rings is NOT true?

The rings must look much the same today as they did shortly after Saturn formed.

According to current understanding, which of the following is required in order for a planet to have rings?

The planet must have many small moons that orbit relatively close to the planet in its equatorial plane.

Jupiter and Saturn are made mostly of what?

Hydrogen and Helium gas

Uranus and Neptune are made mostly of what?

Hydrogen compounds

Jovian planet formation:

beyond the frost line: could accumulate ice Hydrogen compounds are more abundant

Jovian planet differences

amount of Hydrogen and Helium gas accumulated 1. Timing: planet that forms earliest captures the most gas 2. Location: planet that forms in a denser part of the nebula forms its core first

Why are Uranus and Neptune denser than Saturn

because they have less Hydrogen and Helium gas proportionately

Adding mass to a jovian planet compresses the underlying gas layers

Jupiter has so many gases and so it’s denser Greater compression is why Jupiter is not much larger even though it is more massive

Interiors of Jovian planets

no solid surface layers under high pressures and temperatures cores made of hydrogen compounds, metals, and rock layers are different for the different planets

Inside Jupiter

Core: rock, metals, and hydrogen compounds Metallic Hydrogen Liquid Hydrogen Gas Hydrogen High pressure of Jupiter causes the phase of hydrogen to change with depth Hydrogen acts like a metal at great depths because electrons can move freely

Comparing Jovian interiors

cores have similar composition low pressure- Uranus and Neptune cause them not to have metallic hydrogen

Saturn vs Jupiter interiors

same layers as Jupiter.. Metallic hydrogen layers are smaller

Jupiter’s magnetosphere

strong magnetic field gives it an enormous magnetosphere

Jupiter’s atmosphere

Hydrogen compounds form clouds Different cloud layers correspond to freezing points of different hydrogen compounds other jovian planets have similar cloud layers Ammonium sulfide: red/brown Ammonia: white

Saturn’s colors:

Saturn’s layers are similar but are deeper in and farther away from the Sun, more subdued

Methane on Uranus and Neptune

Methane gas absorbs red light and transmits blue light… blue light reflects off methane clouds making planets look blue

Weather of Jovian Planets

all have strong winds and strong storms

Medium and Large moons:

enough self gravity to be spherical lots of ice formed in orbit around jovian planets circular orbits in same direction as planet’s rotation

Small moons

far more numerous not enough gravity to be spherical "potato shaped"

Io:

most volcanically active body in the solar system. Eruptions continue to change Io’s surface. Squished and stretched as it orbits

Why is Io’s orbit so elliptical?

because of orbit of other moons orbital resonance: every 7 days, three moons line up tugs add up making all 3 orbits elliptical

Europa:

tidal stresses crack Europa’s surface ice tidal flexing closes crack, grinds up ice tidal flexing opens crack, leaving two ridges Covered with ice not volcanoes Interior also warmed by tidal heating.. it’s entire surface is an ocean, ice layer on top

Ganymede:

largest moon in the solar system. evidence of geological activity tidal heating and heat from radioactive decay?

Callisto

classic cratered iceball no tidal heating no orbital resonances magnetic field?

Titan

Saturn’s only large moon only moon in the solar system with a thick atmosphere mostly nitrogen Surface: liquid methane, rocks made of ice

Medium moons of Saturn

almost all of them show evidence of past volcanism and or tectonics Enceladus: very large geiser, stripes due to geiser craters on only one side

Medium moons of Uranus

Miranda: varying amounts of geological activity, large tectonic features, few craters

Neptune’s moon Triton

similar to Pluto but larger Evidence of past geological activity

Why are Jovian moons more geologically active than terrestrial planets?

Rocky planets: rock melts at higher temperatures, only large rocky planets have enough heat for activity Icy moons: Ice melts at a low temperature, tidal heating can melt internal ice

What are Saturn’s rings like

made up of tiny individual particles orbit Saturn’s equator very thin

Why do Jovian planets have rings?

all four of them have rings. They formed from dust created in impacts on moons orbiting these planets. Rings aren’t leftover form planet formation. The particles are too small to have survived that long. There must be a continuous replacement of tiny particles.