Astronomy Chapter 22

Jupiter's cloud layers are located at certain levels within the atmosphere where the temperatures are such that _______________________ , _____________________ _______________________ , and _____________ can condense to form ice particles.

Ammonia; ammonium Hydrosulfide; Water

Efficient forward scattering occurs when particles have diameters roughly the same as the wavelength of ______________, roughly a millionth of a meter. Large particles do not scatter light forward, so a ring filled with basketball-size particles would look dark when illuminated from _________________.

Light; Behind

Models comparing Saturn with Jupiter predict that the lower pressure inside Saturn produces a smaller mass of ______________ ___________________ ________________________.

Liquid Metallic Hydrogen

Roughly a quarter of the way to the center, the pressure is high enough to force the hydrogen into being _______________ _____________________ ___________________, which is a very good electrical conductor.

Liquid Metallic Hydrogen

Jupiter is mostly a _____________ planet. It may have a small core of ______________ ___________________ not much bigger than Earth.

Liquid; Heavy Elements

Jupiter is a ________________ world that has no _______________.

Liquid; Surface

Even though the erupting volcanoes of Io pour out about 1 ton of gases per second, the gases leak into space easily because of its _________ ______________ _________________.

Low Escape Velocity

This perfect alignment between Saturn's ___________________ _________ and the __________ _______ ________________ is peculiar, is not observed for any other planet, and is not _______________________.

Magnetic Axis; Axis of Rotation; Understood

Europa's interaction with Jupiter's ____________________ ______________ reveals the presence of a liquid water ocean lying only __________ _______ (about 10 mi) below the icy surface.

Magnetic Field; 15 km

Auroras on Saturn occur in rings around the planet's __________________ __________ and change day by day. Because the magnetic field is not _________________ to the axis of rotation, the auroral rings occur nearly at the planet's ______________________ ___________.

Magnetic Poles; Inclined; Geometrical Poles

The four Galilean moons of Jupiter orbit inside the ___________________________, and some of the heavier ions in the radiation belts come from the innermost moon, ________.

Magnetosphere; Io

Titan is a bit larger than the planet ________________ and almost as large as Jupiter's moon ________________________.

Mercury; Ganymede

Iapetus is an ______________________ moon. Its ________________ side, the side that always faces backward as it orbits Saturn, is old, cratered, icy, and about as bright as dirty snow. Its ________________ side, the side that always faces forward in its orbit, is also old and cratered, but it is much _______________ than you would expect.

Asymmetric; Trailing; Leading; Darker

Saturn's _____________________ blends gradually into its _______________ interior. The size of its core is ___________________.

Atmosphere; Liquid; Uncertain

Titan is a giant ice moon with a thick ____________________ and a mysterious ______________.

Atmosphere; Surface

Jupiter's rings are very bright when illuminated from ________________. In other words, they are scattering light ________________. The ________________ scattering tells you that Jupiter's rings are made mostly of particles about the size of those in smoke.

Behind; Forward; Forward

If a planet and its moon have the same average densities, the Roche limit is at _____________ times the planet's radius.

2.44

Saturn's magnetic field is about ________ times weaker than Jupiter's. It also has correspondingly weaker __________________ ___________.

20; Radiation Belts

The planet contains about _________ Earth masses of elements heavier than helium, but much of that may be ______________________ in the convectively stirred liquid hydrogen. Measurements by orbiting spacecraft indicate that no more than _________ Earth masses are included in a heavy-element core.

30; Suspended; 10

Jupiter is about __________ times Earth's mass.

318

The Great Red Spot storm has been going strong at least since it was first noticed by early telescope observers ___________ years ago.

350

Saturn has more than ___________ moons with charted orbits.

60

Europa's surface reflects an average of _________ percent of the sunlight that hits it.

67 (This further shows that its surface is young because this reflectivity is produced by clean ice)

Liquid Metallic Hydrogen

A form of hydrogen under high pressure that is a good electrical conductor

Irregular Satellites

A moon with an orbit that has large eccentricity or high inclination to the equator of its parent planet or is retrograde; Irregular moons are thought to have been captured

Regular Satellites

A moon with an orbit that has small eccentricity, low inclination to the equator of its parent planet, and is prograde; Regular moons are thought to have formed with their respective planets rather than having been captured

Sheppard Satellites

A satellite that, by its gravitational field, confines particles to a planetary ring

Model calculations show that in the conditions on Titan __________________ could condense from the atmosphere and fall as rain, so planetary scientists hypothesized that Titan should have rivers, lakes, and possibly oceans of ____________________.

Methane; Methane

The vast majority of Jupiter's ring particles must be _________________ _________.

Microscopic Dust

Small __________________ embedded in the rings produce gaps, waves, and scallops in the rings.

Moonlets

How many moons does Jupiter have?

More than 60 (Most of these moons are small and rocky, and many are probably captured asteroids)

Io Flux Tube

A tube of magnetic lines and electric currents connecting Io and Jupiter

How are Saturn's rings labeled?

A, B, C, etc

The closer you get to Jupiter, the more _____________ the moons are.

Active

___________ the Jovian worlds also have giant circulating storms, the primary example of which is Jupiter's _____________ ________ ___________, which is more than ______________ the size of Earth

All; Great Red Spot; Twice

The orbits of some moons may have been modified by interactions with other moons so that they now revolve around their planet in ______________ resonances. The same process may allow moons to affect the orbital motions of __________________ in planetary rings.

Mutual; Particles

Most of Titan's atmosphere is _________________ with about 1.6 percent ________________.

Nitrogen; Methane

Does Europa have a magnetic field?

No (Although tidal heating is enough to keep it active)

Does Io have impact craters?

No (This is surprising since it is the innermost of the Galilean moons. Meaning it must have a very active surface)

Saturn's C ring contains _________________-size chunks of ice, whereas most particles in the A and B rings are more like golf ball to dust-size ice crystals. Further, C ring particles are less than half as _____________ as particles in the A and B rings. The C ring particles also contain less _________ and more ___________________.

Boulder; Bright; Ice; Minerals

Saturn's rings are made of _______________ _________ _____________, but the particles in Jupiter's rings are very ___________ and __________________.

Bright Ice Chunks; Dark; Reddish

Observations show that Ganymede's _______________ ______________ was produced when the icy crust broke and water flooded up from below and froze.

Bright Terrain

Heat flowing upward from the interior causes rising currents in the _____________ _____________, and cooler gas sinks in the ____________ _____________.

Bright Zones; Dark Belts

The youngest craters of Callisto look _____________ because they have dug down to _________________ ice.

Bright; Cleaner

Saturn's rings are ____________, beautiful and composed of billions of _______ particles, each one following its own _____________ around the planet.

Bright; Ice; Orbit

Large summit craters called ________________ and ___________ ________________ are volcanic features that Earth and Io have in common.

Calderas; Lava Curtains

What is Jupiter's outermost moon?

Callisto

____________________ interacts with Jupiter's magnetic field in a way that suggests it has a layer of ___________ liquid water roughly 10 km thick about 100 km (60 mi) below its icy surface.

Callisto; Salty

__________________ _________________ realized that Saturn's rings form a disk surrounding but not touching the planet.

Christiaan Huygens

The large circular or oval spots seen in Jupiter's clouds are _____________________ ______________ that can remain stable for decades or even centuries.

Circulating Storms

The four Galilean moons show a clear sequence of more and more tidal heating the _______________ they are to Jupiter.

Closer

When you look at Jupiter, all you see are _______________.

Clouds

Titan's escape velocity is low, but it is so far from the Sun that it is very ____________, and most ________ atoms don't move fast enough to escape.

Cold; Gas

Jupiter's cloud layers are deathly ______________, and the deeper layers that are ____________________ have a crushingly high pressure.

Cold; Warmer

The atmospheres of Jupiter and Saturn are quite similar once you account for the fact that Saturn is _________________.

Colder

Callisto has no ______________

Core

Model calculations suggest Io contains a modest ____________ of iron or iron mixed with sulfur, a deep rocky ________________ that is partially molten, and a thin, rocky ______________.

Core; Mantle; Crust

The bright terrain on Ganymede has few _________________. That part of Ganymede's surface must be only about _________ ________________ years old.

Craters; One Billion

The pressure and temperature of Jupiter are higher than the ______________ ____________ for hydrogen, and that means there is no difference between ___________________ hydrogen and ________________ hydrogen.

Critical Point; Gaseous; Liquid

______________ _______________________ demonstrated that gaps in Saturn's rings were caused by resonances with some of Saturn's moons.

Daniel Kirkwood

The surface of Callisto is ___________, ___________ ice heavily pocked with craters.

Dark; Dirty

The gaseous atmospheres of the Jovian planets are not very ____________.

Deep; (Jupiter's atmosphere makes up only about 1 percent of its radius)

A newer hypothesis for the Galilean moons proposes that Jupiter's early disk was indeed _____________ and _______ and may have created moons, but those moons spiraled into the planet and were lost. Only later, as the disk grew ________________ and ________________, did the present Galilean moons begin to form.

Dense; Hot; Thinner; Cooler

Callisto has never fully ______________________ to form a dense core and a lower-density mantle.

Differentiated

Titan's surface has dark ___________________ __________________ that lead into dark, smooth areas.

Drainage Networks

Jupiter's magnetic field is produced by the _______________ effect operating in the highly _____________________ liquid metallic hydrogen as it is circulated by _____________________ and spun by the ____________ rotation of the planet.

Dynamo; Conductive; Convectin; Rapid

What are two faint rings of Saturn called?

E and G

Saturn's _________ ring appears to be replenished at least in part by ice crystals blasted into space by the geysers on Enceladus, and the source of the ________ ring seems to be a tiny embedded moonlet discovered in Cassini orbiter images.

E; G

Europa is a bit smaller than what celestial body?

Earth's Moon

On both _____________ and ________________, winds circulate clockwise around the high-pressure areas in the northern hemisphere and counterclockwise south of the equator.

Earth; Jupiter

At its closest point to Earth, Jupiter is about ____________ times farther away than Mars.

Eight

Jupiter's magnetic field interacts with Io to produce a powerful ________________ ________________ (about a million amperes) that flows through a ____________________ ___________ called the Io flux tube from Jupiter out to Io and back to Jupiter. Small spots of bright auroras lie at the two points where the Io flux tube enters Jupiter's _______________________

Electric Current; Curving Path; Atmosphere

Specks of dust become ___________________ charged by sunlight, and Saturn's magnetic field lifts them out of the ring plane.

Electrically

Jupiter is ______________ times the diameter of Earth

Eleven

Tidal heating occurs when changing tides cause friction within a moon that has an _________________ orbit.

Elliptical

With a diameter of only 500 km (310 mi), the moon ___________________ would not be expected to show signs of geologic activity, but it definitely does.

Enceladus

What is the most reflective object in the Solar System?

Enceladus (It has an an albedo of 0.99)

_______, ______________, and __________________ are locked in an orbital resonance; in the time it takes __________________ to orbit once, _______________ orbits twice and _______ four times. This gravitational interaction keeps the orbits, especially ________, slightly eccentric

Io; Europa; Ganymede; Ganymede; Europa; Io; Io's

_________, like ________________, may be a place that humans will never visit in person.

Io; Venus

Any gas atoms on Io that become __________________ are swept away by Jupiter's rapidly rotating magnetic field. The __________ produce a cloud of sulfur and sodium ions in a ______________ (doughnut shape) enclosing Io's orbit.

Ionized; Ions; Torus

__________________ satellites are mostly, if not all, captured objects.

Irregular

Small moons are _____________________ in shape, old surfaces are _________________ cratered, and old icy surfaces are ______________.

Irregular; Heavily; Dark

___________________ satellites, which tend to be smaller than the ___________________ satellites, sometimes have retrograde and/or highly inclined orbits, and are generally far from their parent planet.

Irregular; Regular

Io has a lethal level of radiation. Why is this?

It is deep inside Juipter's magnetosphere and radiation belts.

Galilean moons are on which planet?

Jupiter

Which planet is the ruler of the Solar System?

Jupiter

___________________ contains 71 percent of all the planetary matter in the entire Solar System.

Jupiter

What is the largest Jovian world?

Jupiter (it is 11 times the diameter of Earth)

Belts and Zones are most distinct on which two planets?

Jupiter and Saturn (Dark belts and light zones look like stripes)

What are the two Jovian pairs?

Jupiter and Saturn; Uranus and Neptune

__________________ composition is roughly three-quarters hydrogen and a quarter helium by mass, plus small amounts of water vapor, methane, ammonia, and similar molecules.

Jupiter's

Saturn's atmosphere is much colder than ____________________.

Jupiter's (This makes sense since Saturn is further away from the Sun)

What planets' rings are not easily detectable from Earth?

Jupiter, Uranus, and Neptune (Saturn's are easily detected)

Phoebe is likely to be a captured _______________ __________ _____________ that was originally in an orbit beyond Neptune.

Kuiper Belt Object

How long is Io's orbital period?

Less than Two Days (This shows that Jupiter must be massive)

The visible clouds on Jupiter are composed of _________________ crystals, but models predict that deeper layers of clouds contain __________________ ________________________ crystals, and deeper still lies a cloud layer of __________ droplets.

Ammonia; Ammonium Hydrosuflide; Water (These compounds are normally white, so planetary scientists think the colors arise from small amounts of other molecules formed in reactions powered by lightning or sunlight)

Old, icy surfaces in the Solar System become dark because _____________ ________ radiation and solar wind particles cause chemical changes in the ice and also because meteorite impacts deposit ___________ and vaporize ____________, leaving any dust and rock in the ice behind to form a dirty crust.

Solar UV; Dust; Water

Saturn's auroras vary day by day because of changes in the _____________ ____________.

Solar Wind

Fluctuations in the auroras reveal that the _______________ ____________ buffets Jupiter's magnetosphere, but some of the fluctuations seem to be caused by changes in the ________________________ ________________ deep inside the planet. In this way, studies of the auroras on Jupiter can help astronomers learn more about its ________________ ________________.

Solar Wind; Magnetic Dynamo; Liquid Depths

Jupiter's magnetic field deflects the ______________ ____________ and traps high-energy particles in __________________ ___________ much more intense than Earth's.

Solar Wind; Radiation Belts

Enceladus is venting water, ice, and organic molecules from geysers near its ______________ pole.

South

Ring particles get caught in the most ____________ orbits among the innermost moons. Rings push against the _____________ moons, but those moons are locked in place by resonances with larger, _____________ moons. Without the moons, the rings would spread and __________________.

Stable; Inner; Outer; Dissipate

Titan's rocks that litter the ground are actually ____________-hard chunks of supercold water ice smoothed by __________________.

Steel; Erosion

Jupiter's magnetic field is about 14 times _____________________ than Earth's field.

Stronger

Io's thin atmosphere is smelly with _____________.

Sulfur

Whitish areas on the surface of Io are frosts of ___________ _______________.

Sulfur Dioxide

Io's volcanoes appear to be powered by _____________ _________________ dissolved in the magma. When the __________________ on the magma is released, the ______________ __________________ boils out of solution and blasts gas and ash high above the surface in plumes hundreds of kilometers high.

Sulfur Dioxide; Pressure; Sulfur Dioxide

_______________ venting from Io is constrained by Jupiter's magnetic field to form a ____________ around that moon's orbit.

Sulfur; Torus

Spectra recorded from Earth and from spacecraft visiting Jupiter show that the composition of Jupiter is much like that of the ___________.

Sun

Besides ________________________ the rings with particles, the moons help __________________ the ring particles and keep them from spreading outward.

Supplying; Confine

What is Saturn's largest satellite?

TItan

The poles and equator on Jupiter are about the same ______________________, probably because of heat rising from the interior. Consequently, there are no ____________________ winds, and the planet's rapid rotation stretches the high- and low-pressure areas into ____________ and ____________ that circle the planet.

Temperature; Waveshaped; Belts; Zones

Three cloud layers on Saturn form at about the same respective ________________________ as do the three cloud layers on Jupiter, but they do not form at the same _____________ since Saturn is colder and its clouds form __________________ in its hazy atmosphere. This is why the zones and belt clouds are less _________________ on Saturn

Temperatures; Depth; Deeper; Distinct

Ganymede's magnetic field fluctuates with the _________-hour period of Jupiter's rotation.

Ten (This interaction reveals that the moon has a layer of liquid water about 170 km (110 mi) below its surface)

What is the average age of the surface of Europa? (Judging from its impact scars)

Ten million years

Astronomers estimate that the mass of Jupiter's heavy-element core is no more than __________ Earth masses, but it could be ____________.

Ten; Zero

Belt-Zone Circulation

The atmospheric circulation typical of Jovian planets; Dark belts and bright zones encircle the planet parallel to its equator

Gossamer Rings

The dimmest part of Jupiter's ring, produced by dust particles orbiting near small moons

Io Plasma Torus

The doughnut-shaped cloud of ionized gas that encloses the orbit of Jupiter's moon Io

Oblateness

The flattening of a spherical body, usually caused by rotation

Tidal Heating

The heating of a planet or satellite because of friction caused by tides

Because massive planets like Jupiter draw debris inward, the closer a moon orbits to the planet, the more often it will be struck by meteorites. What is this called?

The inward focusing of meteorites

Roche Limit

The minimum distance between a planet and a satellite that holds itself together by its own gravity; If a satellite's orbit brings it within its planet's Roche limit, tidal forces will pull the satellite apart

Forward Scattering

The optical property of finely divided particles to preferentially direct light in the original direction of the light's travel

Critical Point

The temperature and pressure at which the vapor and liquid phases of a material have the same density

What is the cause of Ganymede's magnetic field?

This is still a puzzle; One hypothesis is that the magnetic field is left over and frozen into the rock from a time when Ganymede was hotter and more active (It is not explained by the dynamo effect and there is not enough heat for it to have a molten metallic core)

_____________ ___________________ is the frictional heating of a body by changing tides.

Tidal Heating

_______________ ____________________ keeps Enceladus active.

Tidal Heating

Io is heated by a stronger version of the kind of ____________ ________________ that has affected Ganymede and Europa.

Tidal Heating (This is what powers this moon)

Since Ganymede orbits so close to Jupiter, what two process is it exposed to that many worlds never experience?

Tidal Heating and Inward Focusing of Meteorites

An episode of ___________ _______________ in Ganymede might have been enough to drive a dynamo to produce a magnetic field and break the crust to make the ______________ terrain.

Tidal Heating; Bright

Saturn has fewer _______________ than Jupiter, but Saturn's are _____________________.

Winds; Stronger (The reason for this is not clear)

Does Jupiter have a magnetic field?

Yes

Has Europa differentiated?

Yes

Are Jupiter's ring particles old or young?

Young

Is Enceladus young or old?

Young

Can you see Jupiter's magnetic field?

No, but you can see the swirling cloud belts

The complex _____________ relationships of Saturn's moons and their evidently intense cratering suggest that the moons have _____________________ and may have __________________ with each other, with comets, and with large planetesimals in the past.

Orbital; Interacted; Collided

Observations made by the Galileo spacecraft show that Jupiter's main ring is densest at its _________________ edge, where the small moon _______________ orbits, and that another small moon, _____________, orbits inside the ring. Clearly these moons must be structurally _________________ to withstand Jupiter's tidal forces.

Outer; Adrastea; Metis; Strong

What is the largest of Saturn's irregular satellites?

Phoebe

___________________ is at the outer fringes of Saturn's satellite family, and it moves in the retrograde direction.

Phoebe

_________________ is probably a captured Kuiper Belt Object, whereas ______________ probably formed with Saturn.

Phoebe; Tethys

___________________ is smaller than Earth's Moon.

Pluto

Titan has lakes of liquid methane in its _______________ regions. _______________________ from the lakes can maintain the 1.4 percent methane gas in the atmosphere, but __________________ eventually destroys methane, so Titan must have a large supply of methane ____________.

Polar; Evaporation; Sunlight; Ice

Jupiter's belt-zone circulation is driven by high and low ___________________ areas comparable to those on Earth.

Pressure

What is the name of a young, identifiable, impact feature on Europa?

Pwyll

Charged particles trapped in Jupiter's magnetosphere form __________________ ___________ encircling the planet. The magnetic equator is tilted about ________ degrees relative to the planet's rotational equator.

Radiation Belts; 10

Jupiter's vast magnetic field traps high-energy particles from the solar wind to form intense ____________________ ____________ and __________________.

Radiation Belts; Auroras

The spacecraft passing through the _______________________ _____________ of Jupiter received radiation doses equivalent to a billion chest X-rays—at least 10,000 times the immediately lethal dose for a human. Some of the electronics on the spacecraft were __________________ by the radiation.

Radiation Belts; Damaged

The ____________ ___________________ and _______________ __________ of Jupiter cause belt-zone circulation in its atmosphere.

Rapid Rotation; Large Size

Grooved Terrain

Region of the surface of Ganymede consisting of bright, parallel grooves

Jovian moons can be classified into what two groups?

Regular Satellites and Irregular Satellites

___________________ satellites, which tend to be large and orbit relatively ___________ to their parent planet, with low inclinations to the planet's ________________, moving in the prograde direction along with most of the objects in the Solar System.

Regular; Close; Equator

Astronomers hypothesize that most or all of Saturn's _______________ moons formed with the planet and that the ___________________ moons are captured.

Regular; Irregular

Where particles orbit in _____________________ with a moon, the moon's gravity triggers _______________ _______________ waves in much the same way that spiral arms are produced in galaxies. These waves spread __________________ through the rings.

Resonance; Spiral Density; Outward

______________________ can trigger tidal heating, and that can in turn __________________ moons and _________________ atmospheres

Resonances; Resurface; Outgas

Saturn has over a thousand __________________ within the rings.

Ringlets

The ____________ of Jupiter, Saturn, Uranus, and Neptune lie within their planets' respective Roche limits.

Rings

The _____________ of Saturn, and of the other Jovian worlds, are created from and controlled by the planet's moons. Without the moons, there would be no _____________.

Rings; Rings

Jupiter's ring particles orbit inside the _______________ ______________.

Roche Limit

The ________________ _______________ is the distance from a planet within which a moon cannot hold itself together by its own gravity.

Roche Limit

If a dust speck gets knocked loose from a larger rock orbiting inside the _____________ ___________, the rock's _________________ cannot hold the dust speck. And the billions of dust specks in the rings can't pull themselves together to make a larger body—a ____________—because of the tidal forces inside the _______________ ____________.

Roche Limit; Gravity; Moon; Roche Limit

Jupiter's average density reveals that it can't contain much ____________.

Rock

Saturn's smaller moons are mixtures of ____________ and _______ and are _________________ cratered.

Rock; Ice; Heavily

Titan is 60/40 mixture of ___________ and _________. Although its core must be _____________, its mantle and crust contain a large amount of _________.

Rock; Ice; Rocky; Ice

Europa has a density of 3 gm/cm^3, so it must be mostly ___________ and ____________, yet its surface is ________.

Rock; Metal; Ice

Ganymede differentiated into a ____________ and ____________ core, an ________-rich mantle, and a crust of ice 500 km (300 mi) thick. It may even have a small inner ____________ core.

Rock; Metal; Ice; Iron

Only near their centers do the Jovian planets have cores of dense material with the composition of _____________ and ____________. None of the Jovian worlds has a definite _____________ surface on which you could walk.

Rock; Metal; Solid

Volcanoes on Io must be erupting molten ____________ and not just liquid _______________. Also, a few isolated mountains exist that are as high as 18 km, twice the height of Mount __________________. _______________ is not strong enough to support such high mountains. These are all indications that the crust of Io is probably ________________ rock.

Rock; Sulfur; Everest; Sulfur; Silicate

Io's interior is _____________.

Rocky

Jupiter's rings are ________________ rather than ____________.

Rocky; Icey

Prograde

Rotation or revolution in the direction in common with most such motions in the Solar System

Larger moons are _________________ and more likely to show signs of _____________________ ______________.

Round; Geological Activity

Spectra show that the blue ice on Europa is stained by ___________ such as those that would be left behind by mineral-rich _____________ welling up from below and evaporating.

Salts; Water

__________________ is less dense than water.

Saturn

Unlike most magnetic fields, ___________________ is not inclined to its axis of rotation.

Saturn's

___________________ was not enough of a heat source during that system's formation to cause the densities of its regular moons to follow the __________________________ sequence.

Saturn; Condensation

The zones and belt clouds are less distinct on __________________ compared with ___________________.

Saturn; Jupiter

The gravitational effects of small moons called ______________________ __________________ can confine some rings in narrow strands or keep the edges of rings sharp. Moons can also produce ______________ in the rings that are visible as tightly wound ringlets.

Shepherd Satellites; Waves

The origin of Iapetus' dark material is unknown, but theorists suspect that the little moon has swept up dark, _________________- and _______________-rich material on its leading side. This could be caused by meteorites striking and eroding the carbonaceous surface of the outermost moon, _________________, and tossing the resulting dust into space to be scooped up eventually by Iapetus.

Silicon; Carbon; Phoebe

Modern astronomers find __________________ gravitational interactions producing complex processes in the rings.

Simple

The Galilean moons as they appear today seem to be the result of a combination of ___________ formation in a hot nebula and ______________ _____________________.

Slow; Tidal Heating

______________ moons can't keep atmospheres, but ________, ____________ moons can

Small; Big; Cold

Tethys has _________________ _____________ and ____________ _____________ on its surface, showing that it has been active.

Smooth Areas; Long Cracks

More than _____________ active volcanoes are visible on Io's surface.

150

Various atoms and molecules emitted by the __________________ moons, including ______________ from Europa's surface, produce a huge but faint emission ________________ surrounding the Jovian system.

Galilean; Water; Nebula

The first spacecraft to enter Jupiter's atmosphere was the ________________ probe.

Galileo (It parachuted through the upper atmosphere of clear hydrogen, released its heat shield, and then sent measurements back to Earth as it descended through layers of increasing pressure in Jupiter's stormy atmosphere until it was finally crushed)

What is the largest moon in the solar system?

Ganymede

Some ___________ in the rings, such as the Cassini Division, are caused by resonances with moons.

Gaps

Europa's __________ ______________ is evidence that moons orbiting deep inside a massive planet's radiation belts are exposed to a form of erosion that is entirely lacking on Earth's Moon.

Gas Cloud

Images from the Voyager and Galileo probes also reveal much fainter rings, called the ______________________ rings, extending _______________ as far from the planet as the main ring. These rings are densest at the orbits of two small moons, ________________ and ______________, more evidence that ring ____________________ are being blasted into space by impacts on the moons.

Gassamer; Twice; Amalthea; Thebe; Particles

Model calculations yield conflicting results as to whether a ______________ ________________ core survives in Jupiter; it may have been mixed in with the ____________________ liquid hydrogen layer.

Heavy Element; Convecting

Saturn should have lost more heat since it formed, so what explains its current overly hot temperature?

Helium droplets that release energy (heat) as they fall inward

Astronomers have calculated models indicating that _______________ in the liquid hydrogen interior is condensing into droplets and falling ______________. The falling droplets, releasing _______________ as they pick up speed, _____________ the planet.

Helium; Inward; Energy; Heat

Orbiting deep inside Jupiter's radiation belts, Europa is bombarded by ____________-energy particles that alter the icy surface. _____________ molecules are freed and broken up, then dispersed into a _____________________-shaped cloud spread round Jupiter and enclosing Europa's orbit.

High; Water; Doughnut

Is Jupiter's interior hot or cold?

Hot

Jovian storms are comparable to Terrestrial ___________________, but they can last for ____________________.

Hurricanes; Centuries

Saturn's atmosphere is rich in __________________ and displays __________-__________ circulation

Hydrogen; Belt-Zone

All the Jovian worlds have ___________________-rich atmospheres filled with _____________.

Hydrogen; Clouds

Saturn's atmosphere is rich in _____________________ and _______________ (see Table 22-1), and models predict that it is mostly liquid ____________________ with a core of _______________ elements.

Hydrogen; Helium; Hydrogen; Heavy

Jupiter and Saturn are composed of liquid ____________________, so the conventional term for these planets, the gas giants, should probably be changed to ______________ giants. Uranus and Neptune are sometimes called the _________ giants because they contain abundant water in solid forms.

Hydrogen; Liquid; Ice

Jupiter's atmosphere is _____________________ rich, and the clouds are confined to a _________________ layer.

Hydrogen; Shallow

The leading side of Saturn's moon ______________ seems to have accumulated a coating of dark material. he poles and trailing side of the moon have much cleaner __________.

Iapetus; Ice

Callisto is a mixture of _________ and ___________.

Ice; Rock

Saturn's other regular moons are _________ and ____________________, but they show some signs of _____________________ ______________.

Icy; Cratered; Geological Activity

Titan's surface consists of _________, ___________________ highlands and __________________ ___________ lowland areas. There are only a few craters, suggesting that geological activity is ______________ craters almost as quickly as they are formed.

Icy; Irregular; Smoother; Dark; Erasing

If a moon follows an orbit that is ________________ to the ring plane, the moon's gravity causes a different kind of wave—_____________ _________________ waves—with ripples extending above and below the ring plane and spreading _______________.

Inclined; Spiral Bending; Inward

Astronomers know Jupiter is hot inside because infrared observations show that Jupiter is glowing strongly in the _______________, radiating 1.7 times more energy than it receives from the __________.

Infrared; Sun

Spiral density waves are to outward as spiral bending waves are to __________________.

Inward

What is the driest world in our Solar System?

Io

_________ is the innermost of the four Galilean moons

Io

___________ is more geologically active than any other object in the Solar System, even more than Earth.

Io

The _______ ____________ ___________ connects the small moon Io to the planet Jupiter and carries a powerful electric current that creates spots of ________________ where it touches the planet's atmosphere.

Io Flux Tube; Auroras

Jupiter's wobbling magnetic field rushes past Io at high speed, sweeping up stray particles, accelerating them to high energy, and spreading them around Io's orbit in a doughnut of ionized gas called the______ ______________ ____________.

Io Plasma Torus

What are the four Galilean moons?

Io, Europa, Ganymede, and Callisto

The Galileo spacecraft found that Ganymede has a magnetic field about __________ percent as strong as Earth's, a small ___________________________ inside Jupiter's enormous magnetosphere.

10; Magnetosphere

The temperature at the surface of Io averages 130 K (__________ degrees F) and its atmospheric pressure is very _________.

-225; Low

What are the three reasons why Jupiter's ring particles are not old?

1.) The pressure of sunlight and Jupiter's powerful magnetic field alter the orbits of the particles, and they gradually spiral into the planet 2.) Dust is also lost from the rings as electromagnetic effects force the particles out of the ring plane to form a low-density halo above and below the rings 3.) The intense radiation around Jupiter can grind dust specks down to nothing in a century or so.

Infrared observations show that Saturn is radiating ___________ times as much energy as it receives from the Sun.

1.8

Io, being closest to Jupiter, suffers the most dramatic tides, with its surface rising and falling by about ____________ ______ (more than 300 ft). The resulting friction is enough to __________ Io's interior and drive ____________________.

100 m; Melt; Volcanism

Although Io is __________ percent farther from Jupiter, it travels __________ times faster in its orbit than does Earth's Moon around Earth.

10; 17

Astronomers hypothesize that as Jupiter grew massive, it would have formed a hot, dense disk of matter around its ______________. The Galilean moons could have _________________ inside that disk with the innermost moons, Io and Europa, forming from ____________ material and the outer moons, Ganymede and Callisto, incorporating more _________. (Please keep in mind that this is a hypothesis and that there are objections to this)

Equator; Condensed; Rocky; Ice (Please keep in mind that this is a hypothesis and that there are objections to this)

The equatorial ridge sits atop an ___________________ _____________, and both ridge and ______________ may have formed when Iapetus was ______________, spun _________________, and was still mostly ____________________.

Equatorial Bulge; Bulge; Young; Rapidly; Molten

Iapetus has an ______________________ ____________ that stands as high as 13 km (8 mi) in some places.

Equatorial Ridge

Like icebergs on the Arctic Ocean, blocks of crust on ________________ appear to have floated apart.

Europa

Many faults are visible on ________________ surface, but very few craters.

Europa's

_________________ hidden ocean might be as deep as 150 km (100 mi), containing _____________ as much water as all the oceans on Earth. It is likely to be rich in dissolved ____________________, which make the water a good electrical conductor and allow it to interact with Jupiter's magnetic field.

Europa's; Twice; Minerals

Compression on Earth pushes up mountain ranges, but no such ranges appear on _________________. The icy crust isn't strong enough to support ridges higher than a ______________________ or so.

Europa; Kilometer

True or False: Volcanism is not continuous on Io.

False (It is continuous)

True or False: Circulation in Jupiter's atmosphere is well understood.

False (It is not)

True or False: Auroras only occur on Earth.

False (They also occur on Jupiter, and Jupiter's auroras are brighter)

True or False: Astronomers have known for centuries that Jupiter has rings.

False (This is true for Saturn, Jupiter's were not discovered until 1979)

True or False: Jovian planets are high density.

False (they are low density)

Compression of Europa's crust is revealed by networks of ______________ and low _______________.

Faults; Ridges

Jupiter's ___________________ shape (Oblateness) shows that the planet cannot be as rigid as a Terrestrial planet and must have a liquid _________________.

Flattened; Interior

No one knows how the differences in Saturn's ring composition arises, but they must be related to the way the rings are _______________ and _________________________.

Formed; Replenished

Iapetus has an albedo of only __________ percent—about as dark as fresh asphalt on a highway.

Four

The inner Galilean moons were cooked by ___________ _____________—possibly enhanced when an _______________ ___________________ developed between Ganymede, Europa, and Io. The innermost moon, ________, was heated so much it lost all of its water, and _______________ retained only a small amount. ___________________ was heated enough to differentiate but retained much of its water. ________________, orbiting far from Jupiter and avoiding orbital resonances, was never heated enough to differentiate.

Tidal Heating; Orbital Resonance; Io; Europa; Ganymede; Callisto

All of Jupiter's larger satellites are _____________ _____________ to its planet, keeping the same side forever facing Jupiter.

Tidally Locked

Because Io is so close to Jupiter, the ___________ it experiences are powerful and should have forced Io's orbit to become ________________ long ago. Io, however, is strongly influenced by its neighboring _____________.

Tides; Circular; Mons

_____________ heat the interiors of some moons and produce _____________________ activity on their surfaces, including volcanoes and lava flows.

Tides; Geological

___________________ surface is mostly frozen water ice with some methane mixed in.

Titan's

True or False: A body's composition depends on the temperature of the material from which it formed.

True

True or False: All of our solar systems' Jovian planets have moons and rings.

True

True or False: Io has active volcanoes that spew gas and ash.

True

True or False: The surface of Europa is active and erases craters almost as fast as they form.

True

True or False: There is enough energy flowing outward of Io to continuously recycle its crust.

True (Deep layers melt, are spewed out through the volcanoes to cover the surface, and are later covered themselves until they are buried so deeply that they are again melted)

True or False: If you parachuted into Jupiter, you would fall through the gaseous atmosphere and notice the density of the surrounding fluid gradually increasing until you were in a liquid, but you would never splash into a liquid surface.

True (This is because the pressure and temperature of Jupiter are higher than the critical point for hydrogen)

The development of Jupiter's atmospheric storms is _____________________, and most eventually ________________.

Unpredictable; Disappear

Saturn's rings are ________________.

Unstable (James Clerk Maxwell mathematically proved this)

The center of Jupiter is five or six times hotter than the surface of the Sun and is prevented from exploding into ____________ only by the tremendous _____________________. If there is a core, it is "rocky" only in the sense that it contains ____________ ___________________.

Vapor; Pressure; Heavy Elements

Spectra of Saturn's rings eventually showed that the particles were mostly ______________ __________.

Water Ice

Enceladus has a weak atmosphere of _____________ ____________ and _________________. It is too small to keep such an atmosphere, so it must be releasing gas ___________________.

Water Vapor; Nitrogen; Continuously

Spectra reveal no trace of _____________ at all, so there is no _________ on Io.

Water; Ice

On Europa, rising currents of _____________ can break through the _________ crust or ___________ surface patches.

Water; Icy; Melt