Discovering the Universe Eighth Edition Discovering the Universe Eighth Edition Neil F. Comins...

Discovering the UniverseDiscovering the UniverseEighth EditionEighth Edition

Discovering the UniverseDiscovering the UniverseEighth EditionEighth Edition

Neil F. Comins • William J. Kaufmann III

CHAPTER 8CHAPTER 8The Outer PlanetsThe Outer Planets

CHAPTER 8CHAPTER 8The Outer PlanetsThe Outer Planets

Key Questions….

• How do we know what we do?

• What value is there to ask these questions, and build probes to answer them?

Essay Questions for the Final

Describe Describe Jupiter'sJupiter's atmosphere. What atmosphere. What are the are the similaritiessimilarities and and differencesdifferences between Jupiter and Saturn?between Jupiter and Saturn?

Describe Describe Jupiter'sJupiter's four largest four largest satellitessatellites. Why are they similar, and why . Why are they similar, and why are they different? are they different?

Essay Questions for the Final

Describe Describe Saturn and itsSaturn and its RingsRings. How did . How did they probably arise? How do we know? they probably arise? How do we know?

What do we now know about What do we now know about TitanTitan? What ? What were the scientific questions we wanted to were the scientific questions we wanted to answer by exploring Titan as we did?answer by exploring Titan as we did?

What are the properties shared by What are the properties shared by UranusUranus and and NeptuneNeptune? How are they unique? ? How are they unique?

In this chapter you will discover…In this chapter you will discover…

Jupiter, an active, vibrant, multicolored world Jupiter, an active, vibrant, multicolored world more massive than all of the other planets more massive than all of the other planets combinedcombined

Jupiter’s diverse system of moonsJupiter’s diverse system of moons

Saturn, with its spectacular system of thin, flat Saturn, with its spectacular system of thin, flat rings and numerous moons, including bizarre rings and numerous moons, including bizarre Enceladus and TitanEnceladus and Titan

What Uranus and Neptune have in common and What Uranus and Neptune have in common and how they differ from Jupiter and Saturnhow they differ from Jupiter and Saturn

8.1 A Different Kind of Planet8.1 A Different Kind of Planet

Our goals for learning:Our goals for learning:What are jovian planets made of?What are jovian planets made of?What are jovian planets like on the inside?What are jovian planets like on the inside?What is the weather like on jovian planets?What is the weather like on jovian planets?

What are jovian planets made What are jovian planets made of?of?

Jovian Planet CompositionJovian Planet CompositionJupiter and SaturnJupiter and Saturn

— Mostly H and He gasMostly H and He gas

Uranus and NeptuneUranus and Neptune— Mostly hydrogen compounds: water (HMostly hydrogen compounds: water (H22O), O),

methane (CHmethane (CH44), ammonia (NH), ammonia (NH33))— Some H, He, and rockSome H, He, and rock

Jovian Planet FormationJovian Planet Formation

Beyond the frost line, planetesimals could Beyond the frost line, planetesimals could accumulate ICE.accumulate ICE.

Hydrogen compounds are more abundant Hydrogen compounds are more abundant than rock/metal so jovian planets got than rock/metal so jovian planets got bigger and acquired H/He atmospheres.bigger and acquired H/He atmospheres.

Jovian Planet FormationJovian Planet Formation

The jovian cores are very similar:The jovian cores are very similar:~ mass of 10 Earths~ mass of 10 Earths

The jovian differences are in the amount of The jovian differences are in the amount of H/He gas accumulated. H/He gas accumulated.

Why did that amount differ?Why did that amount differ?

Differences in Jovian Planet Differences in Jovian Planet FormationFormation

TIMING: The planet that forms earliest TIMING: The planet that forms earliest captures the most hydrogen and helium captures the most hydrogen and helium gas. Capture ceases after the first solar gas. Capture ceases after the first solar wind blew the leftover gas away.wind blew the leftover gas away.

LOCATION: The planet that forms in a LOCATION: The planet that forms in a denser denser part of the nebula forms its core part of the nebula forms its core first. first.

Density DifferencesDensity Differences

0

0.5

1

1.5

2

Jupi

ter

Satu

rn

Ura

nus

Nep

tune

Den

sity

(g/c

c)

Uranus and Uranus and Neptune are Neptune are denser than denser than Saturn because Saturn because they have less they have less H/He, H/He, proportionately.proportionately.

Density DifferencesDensity Differences

0

0.5

1

1.5

2

Jupi

ter

Satu

rn

Ura

nus

Nep

tune

Den

sity

(g/c

c)

But that But that explanation explanation doesn’t doesn’t work for work for Jupiter.Jupiter.

Sizes of Jovian PlanetsSizes of Jovian PlanetsAdding mass to Adding mass to

a jovian planet a jovian planet compresses the compresses the underlying gas underlying gas layers.layers.

Sizes of Jovian PlanetsSizes of Jovian Planets Greater Greater

compression is why compression is why Jupiter is not much Jupiter is not much larger than Saturn larger than Saturn even though it is even though it is three times more three times more massive.massive.

Jovian planets with Jovian planets with even more mass even more mass can be smaller than can be smaller than Jupiter.Jupiter.

What are jovian planets like on What are jovian planets like on the inside?the inside?

Interiors of Jovian PlanetsInteriors of Jovian Planets

No solid surfaceNo solid surfaceLayers under high pressure and Layers under high pressure and

temperaturestemperaturesCores (~10 Earth masses) made of Cores (~10 Earth masses) made of

hydrogen compounds, metals, and rockhydrogen compounds, metals, and rockThe layers are different for the different The layers are different for the different

planets — WHY?planets — WHY?

Inside JupiterInside Jupiter High pressure High pressure

inside of Jupiter inside of Jupiter causes the phase causes the phase of hydrogen to of hydrogen to change with depth.change with depth.

Hydrogen acts like Hydrogen acts like a metal at great a metal at great depths because its depths because its electrons move electrons move freely.freely.

Inside JupiterInside Jupiter The core is The core is

thought to be thought to be made of rock, made of rock, metals, and metals, and hydrogen hydrogen compounds.compounds.

The core is about The core is about the same size as the same size as Earth but 10 times Earth but 10 times as massive.as massive.

Comparing Jovian InteriorsComparing Jovian Interiors

Models suggest that cores of jovian planets have Models suggest that cores of jovian planets have similar composition.similar composition.

Lower pressures inside Uranus and Neptune Lower pressures inside Uranus and Neptune mean no metallic hydrogen.mean no metallic hydrogen.

Jupiter’s MagnetosphereJupiter’s Magnetosphere

Jupiter’s strong magnetic field gives it an enormous Jupiter’s strong magnetic field gives it an enormous magnetosphere.magnetosphere.

Gases escaping Io feed the donut-shaped Io torus.Gases escaping Io feed the donut-shaped Io torus.

Aurora on Jupiter

What is the weather like on What is the weather like on jovian planets?jovian planets?

Jupiter’s AtmosphereJupiter’s Atmosphere Hydrogen compounds Hydrogen compounds

in Jupiter form clouds.in Jupiter form clouds.

Different cloud layers Different cloud layers correspond to freezing correspond to freezing points of different points of different hydrogen compounds.hydrogen compounds.

Other jovian planets Other jovian planets have similar cloud have similar cloud layers.layers.

Jupiter’s Jupiter’s ColorsColors

Ammonium sulfide clouds (NHAmmonium sulfide clouds (NH44SH) reflect red/brown.SH) reflect red/brown. Ammonia, the highest, coldest layer, reflects white.Ammonia, the highest, coldest layer, reflects white.

Saturn’s Saturn’s ColorsColors

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

Methane on Uranus and Methane on Uranus and NeptuneNeptune

Methane gas on Methane gas on Neptune and Neptune and Uranus absorbs red Uranus absorbs red light but transmits light but transmits blue light.blue light.

Blue light reflects Blue light reflects off methane clouds, off methane clouds, making those making those planets look blue.planets look blue.

Jupiter’Jupiter’s Great s Great

Red Red SpotSpot

A storm twice as wide as EarthA storm twice as wide as EarthHas existed for at least 3 centuriesHas existed for at least 3 centuries

Weather on Jovian PlanetsWeather on Jovian Planets

All the jovian planets have strong winds All the jovian planets have strong winds and storms.and storms.

Thought QuestionThought Question

Jupiter does Jupiter does not not have a large metal core have a large metal core like the Earth. How can it have a magnetic like the Earth. How can it have a magnetic field?field?

A.A. The magnetic field is left over from when The magnetic field is left over from when Jupiter accreted.Jupiter accreted.

B.B. Its magnetic field comes from the Sun.Its magnetic field comes from the Sun.

C.C. It has metallic hydrogen inside, which It has metallic hydrogen inside, which circulates and makes a magnetic field.circulates and makes a magnetic field.

D.D. That’s why its magnetic field is weak.That’s why its magnetic field is weak.


Jupiter does Jupiter does not not have a large metal core have a large metal core like the Earth. How can it have a magnetic like the Earth. How can it have a magnetic field?field?

A.A. The magnetic field is left over from when Jupiter The magnetic field is left over from when Jupiter accreted.accreted.

B.B. Its magnetic field comes from the Sun.Its magnetic field comes from the Sun.

C. It has metallic hydrogen inside, which circulates and makes a magnetic field.

D.D. That’s why its magnetic field is weak.That’s why its magnetic field is weak.

What have we learned?What have we learned?

What are jovian planets made of?What are jovian planets made of?— Jupiter and Saturn are mostly made of H and Jupiter and Saturn are mostly made of H and

He gas.He gas.— Uranus and Neptune are mostly made of H Uranus and Neptune are mostly made of H

compounds.compounds. What are jovian planets like on the inside?What are jovian planets like on the inside?

— They have layered interiors with very high They have layered interiors with very high pressure and cores made of rock, metals, and pressure and cores made of rock, metals, and hydrogen compounds.hydrogen compounds.

— Very high pressure in Jupiter and Saturn can Very high pressure in Jupiter and Saturn can produce metallic hydrogen.produce metallic hydrogen.


What is the weather like on jovian What is the weather like on jovian planets?planets?— Multiple cloud layers determine the Multiple cloud layers determine the

colors of jovian planets.colors of jovian planets.— All have strong storms and winds.All have strong storms and winds.

8.2 A Wealth of Worlds: Satellites of Ice 8.2 A Wealth of Worlds: Satellites of Ice and Rockand Rock

Our goals for learning:Our goals for learning: What kinds of moons orbit the jovian planets?What kinds of moons orbit the jovian planets? Why are Jupiter’s Galilean moons geologically active?Why are Jupiter’s Galilean moons geologically active? What geological activity do we see on Titan and other What geological activity do we see on Titan and other

moons?moons? Why are jovian planet moons more geologically active Why are jovian planet moons more geologically active

than small rocky planets?than small rocky planets?

What kinds of moons orbit the What kinds of moons orbit the jovian planets?jovian planets?

Sizes of MoonsSizes of Moons

Small moons (< 300 km)Small moons (< 300 km)— No geological activityNo geological activity

Medium-sized moons (300–1,500 km)Medium-sized moons (300–1,500 km)— Geological activity in pastGeological activity in past

Large moons (> 1,500 km)Large moons (> 1,500 km)— Ongoing geological activityOngoing geological activity

Medium and Medium and Large MoonsLarge Moons

Enough self-gravity Enough self-gravity to be sphericalto be spherical

Have substantial Have substantial amounts of iceamounts of ice

Formed in orbit Formed in orbit around jovian around jovian planetsplanets

Circular orbits in Circular orbits in same direction as same direction as planet rotationplanet rotation

Small MoonsSmall Moons

Far more Far more numerous than numerous than the medium the medium and large and large moonsmoons

Not enough Not enough gravity to be gravity to be spherical: spherical: “potato-shaped”“potato-shaped”

Why are Jupiter’s Galilean Why are Jupiter’s Galilean moons geologically active?moons geologically active?

Io’s Volcanic ActivityIo’s Volcanic Activity

Io is the most volcanically active body in Io is the most volcanically active body in the solar system, but why?the solar system, but why?

Io’s VolcanoesIo’s Volcanoes

Volcanic eruptions continue to change Io’s Volcanic eruptions continue to change Io’s surface.surface.Io Volcanoes IR

Io is squished and stretched as it orbits Jupiter.

But why is its orbit so elliptical?

Tidal HeatingTidal Heating

Every 7 days, these three moons line up.

The tugs add up over time, making all three orbits elliptical.

Orbital Orbital ResonancesResonances

Europa’s Ocean: Waterworld?Europa’s Ocean: Waterworld?

Tidal Stresses Crack Europa’s Tidal Stresses Crack Europa’s Surface IceSurface Ice

Tidal stresses crack Europa’s Tidal stresses crack Europa’s surface icesurface ice

Tidal flexing closes crack, grinds up ice

Tidal flexing opens crack, leaving two ridges

Europa’s Interior Also Warmed by Tidal Europa’s Interior Also Warmed by Tidal HeatingHeating

GanymedeGanymede

Largest moon in Largest moon in the solar systemthe solar system

Clear evidence of Clear evidence of geological activity geological activity

Tidal heating plus Tidal heating plus heat from radio-heat from radio-active decay?active decay?

CallistoCallisto

““Classic” Classic” cratered iceballcratered iceball

No tidal heating, No tidal heating, no orbital no orbital resonancesresonances

But it has But it has magnetic field !?magnetic field !?


How does Io get heated by Jupiter?How does Io get heated by Jupiter?

A.A. Auroras Auroras B.B. Infrared lightInfrared light

C.C. Jupiter pulls harder on one side than the Jupiter pulls harder on one side than the otherother

D.D. VolcanoesVolcanoes

What geological activity do we What geological activity do we see on Titan and other moons?see on Titan and other moons?

Titan’s AtmosphereTitan’s Atmosphere Titan is the only Titan is the only

moon in the solar moon in the solar system which has system which has a thick a thick atmosphere.atmosphere.

It consists mostly It consists mostly of nitrogen with of nitrogen with some argon, some argon, methane, and methane, and ethane.ethane.

Titan’s SurfaceTitan’s Surface

The The HuygensHuygens probe provided a first look at Titan’s surface probe provided a first look at Titan’s surface in early 2005.in early 2005.

It had liquid methane, “rocks” made of ice.It had liquid methane, “rocks” made of ice.

Titan’s “Lakes”Titan’s “Lakes”

Radar imaging of Titan’s surface has Radar imaging of Titan’s surface has revealed dark, smooth regions that may be revealed dark, smooth regions that may be lakes of liquid methane.lakes of liquid methane.

Medium Moons of SaturnMedium Moons of Saturn

Almost all show evidence of past volcanism Almost all show evidence of past volcanism and/or tectonics.and/or tectonics.

Ongoing Activity on EnceladusOngoing Activity on Enceladus

Fountains of ice Fountains of ice particles and particles and water vapor from water vapor from the surface of the surface of Enceladus Enceladus indicate that indicate that geological activity geological activity is ongoing.is ongoing.

Medium Moons of UranusMedium Moons of Uranus Varying amounts Varying amounts

of geological of geological activity occur.activity occur.

Moon Miranda has Moon Miranda has large tectonic large tectonic features and few features and few craters (episode of craters (episode of tidal heating in tidal heating in past?).past?).

Neptune’s Moon TritonNeptune’s Moon Triton Similar to Pluto, Similar to Pluto,

but largerbut larger

Evidence for past Evidence for past geological activitygeological activity

Why are jovian planet moons Why are jovian planet moons more geologically active than more geologically active than

small rocky planets?small rocky planets?

Rocky Planets vs. Icy MoonsRocky Planets vs. Icy Moons

Rock melts at higher Rock melts at higher temperatures.temperatures.

Only large rocky Only large rocky planets have enough planets have enough heat for activity.heat for activity.

Ice melts at lower Ice melts at lower temperatures.temperatures.

Tidal heating can Tidal heating can melt internal ice, melt internal ice, driving activity.driving activity.


What kinds of moons orbit jovian What kinds of moons orbit jovian planets?planets?— Moons of many sizesMoons of many sizes— Level of geological activity depends on Level of geological activity depends on

sizesizeWhy are Jupiter’s Galilean moons Why are Jupiter’s Galilean moons

geologically active?geologically active?— Tidal heating drives activity, leading to Tidal heating drives activity, leading to

Io’s volcanoes and ice geology on other Io’s volcanoes and ice geology on other moons.moons.


What geological activity do we see on Titan What geological activity do we see on Titan and other moons?and other moons?— Titan is the only moon with a thick atmosphere.Titan is the only moon with a thick atmosphere.— Many other icy moons show signs of geological Many other icy moons show signs of geological

activity.activity.

Why are jovian planet moons more Why are jovian planet moons more geologically active than small rocky planets?geologically active than small rocky planets?— Ice melts and deforms at lower temperatures Ice melts and deforms at lower temperatures

enabling tidal heating to drive activity.enabling tidal heating to drive activity.

8.3 Jovian Planet Rings8.3 Jovian Planet Rings

Our goals for learning:Our goals for learning:What are Saturn’s rings like?What are Saturn’s rings like?Why do the jovian planets have rings?Why do the jovian planets have rings?

What are Saturn’s rings like?What are Saturn’s rings like?

What are Saturn’s rings like?What are Saturn’s rings like?

They are made up of numerous, tiny They are made up of numerous, tiny individual particles.individual particles.

They orbit over Saturn’s equator.They orbit over Saturn’s equator.They are very thin.They are very thin.

Earth-Based ViewEarth-Based View

Spacecraft View of Ring GapsSpacecraft View of Ring Gaps

Artist’s Conception of Close-UpArtist’s Conception of Close-Up

Gap MoonsGap Moons Some small Some small

moons create moons create gaps within rings.gaps within rings.

Why do the jovian planets have Why do the jovian planets have rings?rings?

Jovian Ring SystemsJovian Ring Systems

All four jovian planets have ring systems.All four jovian planets have ring systems. Others have smaller, darker ring particles than does Saturn.Others have smaller, darker ring particles than does Saturn.

Why do the jovian planets have Why do the jovian planets have rings?rings?

They formed from dust created in impacts They formed from dust created in impacts on moons orbiting those planets.on moons orbiting those planets.

How do we know this?

How do we know?How do we know?

Rings aren’t leftover from planet formation Rings aren’t leftover from planet formation because the particles are too small to because the particles are too small to have survived this long.have survived this long.

There must be a continuous replacement There must be a continuous replacement of tiny particles.of tiny particles.

The most likely source is impacts with the The most likely source is impacts with the jovian moons.jovian moons.

Ring FormationRing Formation

Jovian planets all have rings because they Jovian planets all have rings because they possess many small moons close-in.possess many small moons close-in.

Impacts on these moons are random.Impacts on these moons are random.Saturn’s incredible rings may be an Saturn’s incredible rings may be an

“accident” of our time.“accident” of our time.


What are Saturn’s rings like?What are Saturn’s rings like?— They are made up of countless individual ice They are made up of countless individual ice

particles.particles.— They are extremely thin with many gaps.They are extremely thin with many gaps.

Why do the jovian planets have rings?Why do the jovian planets have rings?— Ring systems of other jovian planets are much Ring systems of other jovian planets are much

fainter with smaller, darker, less numerous fainter with smaller, darker, less numerous particles.particles.

— Ring particles are probably debris from moons.Ring particles are probably debris from moons.

Summary of Key IdeasSummary of Key Ideas

Jupiter and Saturn Jupiter is by far the largest and most massive planet in Jupiter is by far the largest and most massive planet in

the solar system.the solar system. Jupiter and Saturn probably have rocky cores Jupiter and Saturn probably have rocky cores

surrounded by a thick layer of liquid metallic hydrogen surrounded by a thick layer of liquid metallic hydrogen and an outer layer of ordinary liquid hydrogen. Both and an outer layer of ordinary liquid hydrogen. Both planets have an overall chemical composition very planets have an overall chemical composition very similar to that of the Sun.similar to that of the Sun.

The visible features of Jupiter exist in the outermost 100 The visible features of Jupiter exist in the outermost 100 km of its atmosphere. Saturn has similar features, but km of its atmosphere. Saturn has similar features, but they are much fainter. Three cloud layers exist in the they are much fainter. Three cloud layers exist in the upper atmospheres of both Jupiter and Saturn. Because upper atmospheres of both Jupiter and Saturn. Because Saturn’s cloud layers extend through a greater range of Saturn’s cloud layers extend through a greater range of altitudes, the colors of the Saturnian atmosphere appear altitudes, the colors of the Saturnian atmosphere appear muted.muted.

Jupiter and Saturn

The colored ovals visible in the Jovian The colored ovals visible in the Jovian atmosphere are gigantic storms, some of which atmosphere are gigantic storms, some of which (such as the Great Red Spot) are stable and (such as the Great Red Spot) are stable and persist for years or even centuries.persist for years or even centuries.

Jupiter and Saturn have strong magnetic fields Jupiter and Saturn have strong magnetic fields created by electric currents in their metallic created by electric currents in their metallic hydrogen layers.hydrogen layers.

Jupiter and Saturn Four large satellites orbit Jupiter. The two inner Galilean Four large satellites orbit Jupiter. The two inner Galilean

moons, Io and Europa, are roughly the same size as our moons, Io and Europa, are roughly the same size as our Moon. The two outer moons, Ganymede and Callisto, Moon. The two outer moons, Ganymede and Callisto, are approximately the size of Mercury.are approximately the size of Mercury.

Io is covered with a colorful layer of sulfur compounds Io is covered with a colorful layer of sulfur compounds deposited by frequent explosive eruptions from volcanic deposited by frequent explosive eruptions from volcanic vents. Europa is covered with a smooth layer of frozen vents. Europa is covered with a smooth layer of frozen water crisscrossed by an intricate pattern of long cracks.water crisscrossed by an intricate pattern of long cracks.

The heavily cratered surface of Ganymede is composed The heavily cratered surface of Ganymede is composed of frozen water with large polygons of dark, ancient crust of frozen water with large polygons of dark, ancient crust separated by regions of heavily grooved, lighter-colored, separated by regions of heavily grooved, lighter-colored, younger terrain. Callisto has a heavily cratered ancient younger terrain. Callisto has a heavily cratered ancient crust of frozen water.crust of frozen water.

Jupiter and Saturn Saturn is circled by a system of thin, broad rings lying in Saturn is circled by a system of thin, broad rings lying in

the plane of the planet’s equator. Each major ring is the plane of the planet’s equator. Each major ring is composed of a great many narrow ringlets that consist of composed of a great many narrow ringlets that consist of numerous fragments of ice and ice-coated rock. Jupiter numerous fragments of ice and ice-coated rock. Jupiter has a much less substantial ring system.has a much less substantial ring system.

Titan has a thick atmosphere of nitrogen, methane, and Titan has a thick atmosphere of nitrogen, methane, and other gases, as well as lakes of methane and ethane.other gases, as well as lakes of methane and ethane.

Enceladus has areas with very different surface features: Enceladus has areas with very different surface features: an older, heavily cratered region and a newer, nearly an older, heavily cratered region and a newer, nearly crater-free surface created by tectonic activity.crater-free surface created by tectonic activity.

Uranus and Neptune Uranus and Neptune are quite similar in appearance, mass, Uranus and Neptune are quite similar in appearance, mass,

size, and chemical composition. Each has a rocky core size, and chemical composition. Each has a rocky core surrounded by a thick, watery mantle; the axes of their surrounded by a thick, watery mantle; the axes of their magnetic fields are steeply inclined to their axes of rotation; magnetic fields are steeply inclined to their axes of rotation; and both planets are surrounded by systems of thin, dark and both planets are surrounded by systems of thin, dark rings.rings.

Uranus is unique in that its axis of rotation lies near the plane Uranus is unique in that its axis of rotation lies near the plane of its orbit, producing greatly exaggerated seasons on the of its orbit, producing greatly exaggerated seasons on the planet.planet.

Uranus has five moderate-sized satellites, the most bizarre of Uranus has five moderate-sized satellites, the most bizarre of which is Miranda.which is Miranda.

Triton, the largest satellite of Neptune, is an icy world with a Triton, the largest satellite of Neptune, is an icy world with a tenuous nitrogen atmosphere. Triton moves in a retrograde tenuous nitrogen atmosphere. Triton moves in a retrograde orbit that suggests it was captured into orbit by Neptune’s orbit that suggests it was captured into orbit by Neptune’s gravity. It is spiraling down toward Neptune and will eventually gravity. It is spiraling down toward Neptune and will eventually break up and form a ring system.break up and form a ring system.

Key TermsKey Terms

A ringB ringbeltCassini divisionC ringdifferential rotationEncke divisionF ringGalilean moon (satellite)Great Dark SpotGreat Red Spothydrocarbon

liquid metallic hydrogenoccultationpolymerprograde orbitresonanceretrograde orbitringletRoche limitshepherd satellite (moon)spokezone

WHAT DID YOU THINK?

Is Jupiter a “failed star”? Why or why not?Is Jupiter a “failed star”? Why or why not?No. Jupiter has 75 times too little mass to No. Jupiter has 75 times too little mass to

shine as a star.shine as a star.

WHAT DID YOU THINK?

What is Jupiter’s Great Red Spot? What is Jupiter’s Great Red Spot? The Great Red Spot is a long-lived, oval The Great Red Spot is a long-lived, oval

cloud circulation, similar to a hurricane on cloud circulation, similar to a hurricane on Earth.Earth.

WHAT DID YOU THINK?

Does Jupiter have continents and oceans?Does Jupiter have continents and oceans?No. Jupiter is surrounded by a thick No. Jupiter is surrounded by a thick

atmosphere primarily of hydrogen and atmosphere primarily of hydrogen and helium that gradually becomes liquid as helium that gradually becomes liquid as you move inward. The only solid matter in you move inward. The only solid matter in Jupiter is its core.Jupiter is its core.

WHAT DID YOU THINK?

Is Saturn the only planet with rings? Is Saturn the only planet with rings? No. All four outer planets (Jupiter, Saturn, No. All four outer planets (Jupiter, Saturn,

Uranus, and Neptune) have rings.Uranus, and Neptune) have rings.

WHAT DID YOU THINK?

Are the rings of Saturn solid ribbons? Are the rings of Saturn solid ribbons? No. Saturn’s rings are all composed of No. Saturn’s rings are all composed of

thin, closely spaced ringlets consisting of thin, closely spaced ringlets consisting of particles of ice and ice-coated rocks. If particles of ice and ice-coated rocks. If they were solid ribbons, Saturn’s they were solid ribbons, Saturn’s gravitational tidal force would tear them gravitational tidal force would tear them apart.apart.

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