Deck 13: Jupiter and Saturns Satellites of Fire and Ice

Question 1

When Galileo first discovered the large moons of Jupiter in 1610, he called them:

A)Matthew, Mark, Luke, and John.
B)the Medicean stars.
C)the Papal Planets.
D)the Galilean satellites.

Answer 1

B

Question 2

What can we say about the observations of the four large satellites of Jupiter before Galileo's telescopic observation of 1610?

A)The moons individually are bright enough to be visible to the naked eye, so they were undoubtedly observed before 1610. But such observations were not made public, most likely out of fear of contradicting established dogma.
B)The moons individually are bright enough to be visible to the naked eye, but their angular separation from bright Jupiter is too small to allow them to be resolved individually without a telescope. Therefore, they could not have been observed before 1610.
C)The moons individually are not bright enough to be seen without a telescope, so they could not have been observed before 1610.
D)The moons individually are not bright enough to be seen without a telescope, but a conjunction of all four does make them visible to the naked eye. There were a few reliable reports of such an observation before 1610.

Answer 2

B

Question 3

The four major satellites of Jupiter are collectively named after which early astronomer?

A)Copernicus
B)Newton
C)Ptolemy
D)Galileo

Answer 3

D

Question 4

How many satellites of Jupiter were seen by Galileo?

A)12
B)None-he was unable to see them with the naked eye.
C)4
D)1

Question 5

It has been known that Jupiter has satellites since:

A)the time of the ancient Greeks.
B)the Voyager flybys in 1979.
C)Galileo turned his telescope to the sky in 1610.
D)Isaac Newton predicted their existence in 1708.

Question 6

How many large, spherical satellites are in orbit around Jupiter?

A)0
B)16
C)11
D)4

Question 7

Which spacecraft reached Jupiter most recently?

A)Ulysses
B)Juno
C)New Horizons
D)Galileo

Question 8

Which of the following motions is seen to be characteristic of the four Galilean satellites of Jupiter?

A)They orbit the planet in a planar orbit carrying them over both the north and south poles of Jupiter.
B)They orbit the planet in the opposite direction to the planet's rotation.
C)They each keep the same face toward the Sun at all times.
D)They each keep the same face toward the planet at all times.

Question 9

Because of mutual gravitational forces between the satellites and the planet, the orbital periods of the three inner Galilean satellites of Jupiter are in the ratio:

A)1:2:3.
B)1:10:100.
C)1:1:1-equal orbital periods.
D)1:2:4.

Question 10

If the orbital period of Io, the innermost Galilean satellite of Jupiter, is 1.77 days, what is the rotation period around its own axis?

A)3.54 days-twice the orbital period
B)1.77 days - same as orbital period
C)1.18 days-two-thirds of the orbital period
D)5.31 days-3 times the orbital period

Question 11

What is the relationship between the orbital periods of the four Galilean satellites of Jupiter?

A)1:2:4:8-Europa takes twice as long to orbit Jupiter as Io, Ganymede takes twice as long as Europa, and Callisto takes twice as long as Ganymede.
B)1:2-Europa takes twice as long to orbit Jupiter as Io, but there is no simple integer relationship between Callisto, Ganymede, and Europa.
C)The periods appear to be random, with no simple relationship between them.
D)1:2:4-Europa takes twice as long to orbit Jupiter as Io, and Ganymede takes twice as long as Europa, but there is no simple integer relationship between Callisto and Ganymede.

Question 12

Three of the Galilean satellites of Jupiter have orbital periods that are in the ratio 1:2:4. The Galilean satellite that does NOT have such a relationship is:

A)Io.
B)Europa.
C)Ganymede.
D)Callisto.

Question 13

Io, Europa, and Ganymede have orbital periods in the ratio 1:2:4. At some time all three satellites are lined up on the same side of Jupiter as seen from Earth. After Europa goes once around Jupiter:

A)all three satellites will again be lined up on the same side of Jupiter.
B)all three satellites will again be lined up, but Ganymede will be on the opposite side of Jupiter.
C)observers on Europa would not be able to see Io.
D)observers on Earth will not be able to see Ganymede.

Question 14

If the orbital period of Jupiter's satellite Ganymede is 7.15 days, what would be the view from a point on its surface at the equator?

A)Jupiter and the Sun would rise and set with a period of about 7.15 days.
B)Jupiter, if visible, would always remain at the same point in the sky, but the Sun would rise and set with a period of about 7.15 days.
C)The Sun, if visible, would always be at the same point in the sky, but Jupiter would rise and set with a period of about 7.15 days.
D)The Sun and Jupiter would remain fixed in the sky above Ganymede.

Question 15

In terms of the relationship between the periods P and semimajor axes a of their orbits around Jupiter, how do the satellites of Jupiter behave?

A)The satellites do not obey the Keplerian relation P² = ka³, where k is the same constant for each satellite, because they orbit Jupiter and not the Sun.
B)The satellites do obey the Keplerian relation P² = ka³, in which k is the same for planetary motion around the Sun, because it is a universal constant.
C)The satellites do follow the Keplerian relationship P² = ka³, where k is a constant (the same for each satellite) that is different from the constant governing planetary motion around the Sun.
D)The satellites do not obey the Keplerian relation P² = ka³, because their motion about Jupiter is affected by Jupiter's motion about the Sun.

Question 16

In describing the observations of the movements of the satellites of Jupiter, what is the difference between an occultation and an eclipse?

A)An occultation is the passage of the satellite into Jupiter's shadow, whereas an eclipse is the disappearance of the satellite behind the planet.
B)There is no difference-these terms both describe the disappearance of the satellite behind the planet.
C)An occultation is the passage of the satellite in front of the planet, whereas an eclipse is the disappearance of the satellite behind the planet.
D)An occultation is the disappearance of the satellite behind the planet, whereas an eclipse is the passage of the satellite into Jupiter's shadow.

Question 17

It is rare to see Jupiter's Galilean satellites occult one another. Why is such an event seen only rarely?

A)The satellites are very small and move very rapidly, so the occultation happens very quickly and it is easy to miss.
B)The orbits of these satellites are in different planes, so the satellites themselves are rarely along our line of sight at the same time.
C)The orbits of these satellites all lie very nearly in the same plane, but Earth only occasionally crosses this plane.
D)The occultations occur most often when the satellites are on the far side of Jupiter, not visible from Earth.

Question 18

Suppose you have calculated the speed of Ganymede in its orbit from Kepler's laws. You time the interval between when Ganymede first begins to disappear into Jupiter's shadow and when it is totally occulted by Jupiter. What can you calculate from this information?

A)the radius of the orbit of Ganymede
B)the rotational period of Ganymede
C)the orbital period of Ganymede
D)the radius of Ganymede

Question 19

Of the spacecraft that have visited Jupiter, which was placed in orbit around the planet?

A)None of them. They all provided flyby views as they traveled to other planets.
B)Pioneer
C)Voyager
D)Galileo

Question 20

Which of the following properly lists the planets and satellites of planets in order of decreasing density?

A)Mercury, Io, the Moon, and Europa
B)Mercury, the Moon, Io, and Europa
C)the Moon, Mercury, Io, and Europa
D)Europa, Mercury, the Moon, and Io

Question 21

What has proven to be the best method for measuring the mass of a Galilean satellite of Jupiter?

A)observing its orbital motion around Jupiter and applying Kepler's laws
B)measuring the density of material using a lunar lander vehicle and multiplying this density value by the satellite's volume
C)measuring the mutual gravitational disturbances of the orbits of neighboring satellites by the satellite
D)observing the slight changes in the motion of a spacecraft caused by gravitational force, as the spacecraft passed near the satellite

Question 22

Earth-based observations of the motions of Jupiter's large satellites have resulted in measurements of the mass(es) of:

A)only Io.
B)the two inner satellites.
C)all four satellites.
D)only Jupiter itself.

Question 23

To determine the mass of Io you would need:

A)the mass of Jupiter and the orbital radius of Io.
B)spectrographic information from Io.
C)careful observation of the motions of Europa.
D)careful observations of the motions of a spacecraft near Io.

Question 24

The densities of the four Galilean satellites of Jupiter are:

A)all low, typical of rock and ice, because they formed in the outer solar system.
B)very low because, as with Jupiter, they are composed mostly of hydrogen.
C)high (rocky) for the two inner satellites because they formed close to Jupiter, low (rock and ice) for the two outer satellites because they formed farther away from Jupiter.
D)all high, typical of rock, because they are planetary satellites (similar to the Moon).

Question 25

The average densities of the Galilean satellites of Jupiter follow which pattern with increasing distance from the planet?

A)Average density is the same for all satellites, because they were made from the same material.
B)Average density increases with distance from the planet.
C)Average density shows NO pattern with distance, the highest-density satellite being Ganymede, the largest satellite.
D)Average density decreases with distance from the planet.

Question 26

What observation leads to the conclusion that the two outer Galilean satellites of Jupiter are composed of roughly equal parts of rock and water ice?

A)Their densities are very low compared to other objects of comparable size such as the Moon or Mercury.
B)Their highly variable and localized magnetic fields closely resemble that of a mixture of iron rocks and water ice.
C)Their rotations show variations that are thought to be due to changes in shape; this could only happen if they were composed of a loose mixture of rocks embedded in the flexible ice.
D)Images of their surfaces show equal parts of rock and ice.

Question 27

The most definitive evidence for water ice on Jupiter's satellites has come from:

A)analysis of the albedos of these satellites.
B)spectroscopic observations.
C)photographic images of the surfaces from the Galileo flyby mission.
D)temperature analysis of conditions on the surfaces.

Question 28

Which of the Galilean satellites of Jupiter does not have evidence of water ice?

A)Io
B)Europa
C)Ganymede
D)Callisto

Question 29

The four Galilean satellites of Jupiter do not all have the same mean density because:

A)heat from Jupiter prevented ice from forming at the locations of the inner satellites.
B)heat from the Sun prevented ice from forming in the outer part of the "jovian nebula," from which the satellites formed.
C)the larger satellites are more gravitationally compressed.
D)the satellites formed at different distances from the Sun and were later captured by Jupiter.

Question 30

Looking at the geologies of the four large Galilean satellites of Jupiter, we find:

A)remarkable uniformity.
B)totally random characteristics, suggesting that these three satellites were formed at various locations far distant from Jupiter and later captured by Jupiter's gravity.
C)characteristics that change in an orderly fashion with the satellites's distances from Jupiter.
D)two unique sets of characteristics: Io and Callisto being very similar to each other and Europa and Ganymede being similar to each other, but different from Io and Callisto.

Question 31

In what important way does the Jupiter satellite system resemble a miniature solar system, perhaps providing a hint to the initial formation of both systems?

A)The reflectivity of their surfaces decreases, the farther away they are from the central object, because the nearer objects have thicker clouds around them.
B)Average density of objects decreases as distance increases from the central object, because the heat from this object would have melted and evaporated the volatile low-density ices from the closer objects.
C)Average density of objects increases the farther away they are from the central object, because this central object can attract high-density material over a greater range of distances than for low-density material.
D)The masses of objects increase as distance increases from the central object, because the probability of accretion of small objects into larger objects increases with distance.

Question 32

If we consider the formation of the jovian system as analogous to the formation of the solar system, the "snow line" in the jovian system would be:

A)inside the orbit of Io.
B)between the orbits of Io and Europa.
C)between the orbits of Europa and Ganymede.
D)between the orbits of Ganymede and Callisto.

Question 33

In composition and density:

A)Io and Europa are more like Mars, whereas Ganymede and Callisto are more like Jupiter.
B)Io and Europa are more like Jupiter, whereas Ganymede and Callisto are more like Mars.
C)Io and Callisto are more like Mars, whereas Europa and Ganymede are more like Jupiter.
D)Io and Callisto are more like Jupiter, whereas Europa and Ganymede are more like Mars.

Question 34

Our solar system might have become a double star system if Jupiter had been formed with enough mass to undergo nuclear fusion. Approximately what percent of the Sun's mass would Jupiter have needed for this to happen? (The mass of the Sun is 2.0 × 10³⁰ kg.)

A)0.08%
B)0.8%
C)8%
D)80%

Question 35

In order to ignite nuclear fusion in its interior, Jupiter would have to have a mass about how many times its present mass?

A)0.08
B)0.8
C)8
D)80

Question 36

The most active volcanic object in the solar system is:

A)Earth, with many continuously active volcanoes and numerous earthquakes.
B)Io, the inner Galilean satellite of Jupiter.
C)Venus, its high surface temperature indicating molten lava while its cloud cover is made up of volcanic gases.
D)the Moon, where volcanism is causing many new craters per year.

Question 37

Volcanoes on the surface of Io are distributed:

A)around the equator.
B)near the poles.
C)in long arcs corresponding to tectonic plate boundaries.
D)over the whole surface.

Question 38

The heating of the interior of the large Galilean satellite Io of Jupiter, in order to produce volcanic activity, is probably caused by:

A)its original heat of formation.
B)radioactive elements in its surface.
C)nuclear fission within its interior.
D)tidal distortion by Jupiter and its other satellites.

Question 39

The heating of the interior of Io, the innermost Galilean satellite of Jupiter, is caused by:

A)continual bombardment by meteoroids attracted by Jupiter's enormous gravitational pull.
B)thermal heating from Jupiter, because Jupiter emits more radiation than it receives from the Sun.
C)the fact that Io moves inside Jupiter's magnetosphere, where the temperature is as high as anywhere in the solar system.
D)continuous tidal distortion by Jupiter and the other satellites.

Question 40

The source of intense heating in the interior of Jupiter's satellite Io, causing continuous and intense volcanic activity, is:

A)tidal flexing and distortion, caused by Jupiter and the other large satellites.
B)frictional heating as the solar wind impacts on the satellite surface.
C)solar UV and visible radiation.
D)heat released by continuous shrinkage after creation, transforming potential gravitational energy to heat.

Question 41

Io, one of the major Jupiter satellites, is undergoing extensive volcanic activity associated with interior heating that is caused by:

A)original heat, caused by gravitational condensation at the satellite's formation.
B)solar radiation and heat falling on the surface.
C)the impact of Jupiter's Van Allen particles on Io's surface.
D)tidal distortion and internal friction because of flexing.

Question 42

Which one of the following changes would decrease volcanic activity on Io?

A)Increase the masses of Europa and Ganymede.
B)Decrease the distances from Io to Europa and to Ganymede.
C)Increase the distance from Jupiter to Io.
D)Increase the mass of Jupiter.

Question 43

Extensive volcanic activity observed on Jupiter's satellite Io is caused by:

A)tidal stresses from Jupiter and the other Galilean satellites.
B)"primordial" heat remaining from the release of gravitational energy during Io's formation.
C)frictional heating between the satellite's mantle and crust during plate movement, driven by convection.
D)heat released by radioactivity in Io's core and mantle.

Question 44

The lava flows from the volcanoes of Io produce lava, which is hotter than typical lava from terrestrial volcanoes. The lava on Io is believed to be:

A)superheated water.
B)liquid sulfur.
C)lava enriched with magnesium and iron.
D)pure molten iron.

Question 45

The numerous small black spots on Jupiter's satellite Io appear to be:

A)impact craters.
B)rocky outcrops.
C)volcanic vents.
D)sulfur deposits.

Question 46

Which chemical or chemicals appear to play a prominent role in the eruptive plumes of Io?

A)methane and ammonia
B)molten lava
C)sulfur and sulfur dioxide
D)water and steam

Question 47

What is estimated to be the annual thickness of the layer of sulfur-laden material laid down by the "volcanoes" on Jupiter's Galilean satellite Io?

A)1 m
B)1 cm
C)10 m
D)about 1 mm

Question 48

Why does the innermost Galilean satellite of Jupiter, Io, not show a cratered surface, as expected from the appearance of equivalent-sized objects like the Moon, Mercury, and Mars?

A)The large gravitational force generated by Jupiter has diverted most objects away from Io.
B)The surface is completely covered by an ocean of water, partly frozen into ice, which will obviously not show craters.
C)Volcanic action recoats the surface regularly and continuously.
D)Dust storms triggered by heating from Jupiter have quickly filled in any craters.

Question 49

Why would you expect to see no craters, such as those on the Moon or Mars, on Io, the innermost Galilean satellite of Jupiter?

A)The surface is always reentering the planet's interior by subduction in rapid plate tectonic motion, similar to but faster than that on Earth.
B)Continuous rainfall quickly erodes and washes away all trace of craters.
C)Its liquid surface cannot maintain a crater, just as Earth's oceans cannot do.
D)Volcanoes are continuously depositing new material on the surface.

Question 50

Jupiter's magnetic field is caused by:

A)the planet's rapid rotation coupled with liquid metallic hydrogen in its interior.
B)electronic currents passing between the Io torus and Jupiter.
C)induction effects that occur when Io passes along the Io torus.
D)concentrated effects of the plasma tori of all four Galilean satellites.

Question 51

How is the Io plasma torus formed?

A)Io's motion through Jupiter's magnetosphere creates currents of electrons and charged particles in a loop between Io and Jupiter's north and south magnetic poles.
B)Io disturbs Jupiter's magnetosphere, causing magnetospheric-charged particles to collect in a ring around Io's orbit.
C)Charged particles from Jupiter's magnetosphere ionize and eject atoms from Io's surface and from its volcanic plumes.
D)Io's volcanic plumes propel neutral atoms into orbit around Jupiter, where they are then ionized by high-energy charged particles in Jupiter's magnetosphere.

Question 52

Jupiter's satellite Io has a surprisingly large magnetic field. This field is believed to:

A)be produced in the neighboring large satellites Europa and Ganymede.
B)originate in the Io torus, a ring of charged particles in Jupiter's magnetosphere.
C)be a result of the solar wind interacting with Jupiter's magnetosphere.
D)be induced magnetism from Jupiter's strong magnetic field.

Question 53

Io has a large magnetic field. About how much of this field is created by induction rather than being generated independently by Io itself?

A)none of the field
B)10% of the field
C)half of the field
D)all of the field

Question 54

The main source of the charged particles in Jupiter's magnetosphere is:

A)the solar wind.
B)cosmic rays from beyond the solar system.
C)the atmosphere of Jupiter itself.
D)Io.

Question 55

What is the relationship between Io and the aurorae in Jupiter's atmosphere?

A)Io blocks the motion of charged particles in Jupiter's magnetosphere, creating a shadow, or dark spot, in Jupiter's aurorae.
B)Io's gravitational pull raises tides in Jupiter's atmosphere, and the atmosphere emits light (aurorae) as it rises and falls through Jupiter's strong magnetic field.
C)The motion of Jupiter's magnetic field past Io generates electric currents between Io and Jupiter, which create aurorae at specific locations near Jupiter's magnetic poles.
D)Sulfurous solid particles ejected from Io's volcanoes fall into Jupiter's atmosphere, where they are ionized and emit light.

Question 56

As a result of measurements by the Galileo spacecraft, what is now believed to be the internal structure of Io?

A)a thick mantle of rock over a core of iron and iron sulfide
B)a thick mantle of ice over a core of rock
C)entirely or almost entirely rock, with no evidence of ice or a differentiated metallic core
D)a thick crust of ice over a rocky mantle and a small, possibly molten, iron core

Question 57

Based on its average density of 3020 kg per cubic meter and its smooth surface, what is thought to be the internal structure of Jupiter's satellite Europa?

A)metallic core, rocky mantle, and a 100- to 200-km-thick ocean of ice and water
B)almost entirely ice, with only a small, rocky core
C)entirely rock except for a metallic core about 300 km in diameter
D)half rock and half ice, with the rock forming the core and the ice forming the mantle

Question 58

What does the surface of Europa, a satellite of Jupiter, look like?

A)It is entirely ice, with fractures and ridges going in every direction and no features more than about 100 m high.
B)It is entirely ice, with light and dark areas containing many impact craters and parallel ridges up to about 1 km high.
C)The surface is rocky and densely cratered, except for a few large, dark, relatively uncratered plains.
D)We don't know; the surface is hidden below a dense layer of clouds.

Question 59

The origin of the very thin oxygen atmosphere around Europa is:

A)from electrolysis of water into O₂ and H₂ in the ocean under the ice, as a result of intense electrical currents induced by Europa's motion through Jupiter's magnetic field.
B)from photosynthesis in primitive plant life living in the deep oceans beneath the ice surface.
C)the dissociation of water molecules by solar UV radiation.
D)the breakup of water molecules by the impact of ionized material from Jupiter's magnetosphere.

Question 60

The weak and variable magnetic field measured by the Galileo spacecraft on Europa is generated by:

A)its magnetized solid iron core.
B)electrical currents between the satellite and Jupiter, through the conducting magnetosphere.
C)the motion of molten iron in Europa's core.
D)electrical currents in the ocean water, induced by Europa's motion through Jupiter's intense magnetic field.

Question 61

Which of the following features have NOT been found on Europa, one of the Galilean satellites of Jupiter?

A)mountains
B)craters
C)ice
D)cracks running along the surface

Question 62

Europa does not generate a satellite-wide magnetic field of its own. Each of the following contributes to the lack of such a field, EXCEPT one. Which is the exception?

A)Europa is very small in comparison to most bodies that produce their own magnetic fields.
B)Europa rotates slowly on its axis.
C)Europa does not have a large, molten iron core.
D)Europa has no electrically conducting liquid within it.

Question 63

Observations indicate that a large electric current flows through Europa, induced by Jupiter's magnetosphere sweeping over the planet. This requires an electrically conducting medium under the surface. In the case of Europa, this medium is believed to be:

A)liquid metallic hydrogen.
B)molten iron.
C)ionized water.
D)a plasma of sulfur and sulfur dioxide.

Question 64

How thick is the layer of surface ice on Europa thought to be?

A)a few meters
B)several hundred meters
C)10 km
D)100 km

Question 65

How deep is the subsurface ocean on Europa thought to be?

A)a few kilometers
B)50 km
C)100 km
D)over 500 km

Question 66

The largest satellite (moon) in our planetary system is:

A)Earth's Moon.
B)Titan, a satellite of Saturn.
C)Phobos, one of Mars's moons.
D)Ganymede, a satellite of Jupiter.

Question 67

What conclusions were reached about the nature of the four Galilean satellites in orbit around Jupiter when images were first sent back from exploring spacecraft?

A)The satellites were very different from Earth's Moon in nature but very similar to each other.
B)The satellites all seemed to have surfaces of water ice, maybe with underlying oceans of water.
C)The satellites were fundamentally different from anything seen before and radically different from each other.
D)The satellites were all found to be similar to Earth's Moon in surface color and details.

Question 68

The outer three Galilean satellites of Jupiter differ from Io, the innermost such satellite, by having surfaces of:

A)water ice.
B)smoothly polished rock.
C)carbon dioxide.
D)sulfur.

Question 69

Ganymede, one of the large Galilean satellites of Jupiter, is very different from Earth, but in which one of the following ways does Ganymede resemble Earth?

A)Like Earth, but unlike all other satellites in the solar system, Ganymede has a dense atmosphere.
B)Based on its density, Ganymede appears to have a large iron core surrounded by a thick rocky mantle directly beneath its icy crust.
C)Ganymede has active volcanoes.
D)Ganymede appears to have had tectonic activity at some time in its past.

Question 70

The surfaces of Ganymede and Callisto appear to consist of:

A)sulfur.
B)ices of methane, ammonia, and water.
C)rocks and lava.
D)water ice.

Question 71

What appears to be the origin of the light, grooved terrain on the surface of Ganymede?

A)cracking of the surface due to shrinkage of the satellite as it cooled
B)impacts by cometary debris
C)tidal flexing by Jupiter
D)expansion and cracking of the surface as the ice froze

Question 72

The structure of Ganymede, a Galilean satellite of Jupiter, is thought to be:

A)a thick crust of ice, a rocky mantle, and metallic core.
B)about half rock and half ice, with the rock at the center and the ice outside.
C)a large rocky core with a thin layer (100 km thick) of ice and water over it.
D)mostly or entirely rock with no firm evidence of an iron core, but with active volcanoes on its surface.

Question 73

Which of the large satellites of the jovian planets appears to have a significant and permanent magnetic field?

A)Europa
B)Ganymede
C)Callisto
D)Titan

Question 74

Which Galilean satellite shows evidence of tectonic activity?

A)Io
B)Europa
C)Ganymede
D)Callisto

Question 75

Which Galilean satellite shows evidence of an intrinsic (rather than induced) magnetic field?

A)Io
B)Europa
C)Ganymede
D)Callisto

Question 76

Which of the following statements describes the surface of Callisto, the outer Galilean satellite of Jupiter?

A)dark, rocky surface with a thin ice frost that occasionally disappears by evaporation in sunlight
B)ammonia and methane ice surface, with methane clouds above it, making the satellite appear very bright
C)sulfur-coated surface, with molten sulfur lakes and active volcanoes
D)ice-covered surface with dark coating, maybe of meteoritic dust or hydrocarbon material, making the satellite appear dark

Question 77

The structure of Callisto, the outer Galilean satellite of Jupiter, is thought to be:

A)a thick ice crust and a slushy mantle of ice and water over a core of rock.
B)mostly or entirely rock with no firm evidence of an iron core, and active volcanoes on its surface.
C)a large rocky core with a thin layer (100 km thick) of ice and water over it.
D)a jumbled mixture of about half rock and half ice.

Question 78

Callisto is believed to have each of the following features EXCEPT one. Which is the exception?

A)a thin atmosphere
B)an induced magnetic field
C)extensive crater fields containing many craters of all sizes
D)an icy but relatively dark surface

Question 79

The surface of Callisto, the outer Galilean satellite of Jupiter, can best be described as:

A)relatively smooth, with a great many impact craters and one large basin created by an asteroid impact.
B)very smooth, with a network of streaks and cracks and very few craters.
C)rough and mountainous, with evidence of volcanic or geyser-like activity.
D)relatively smooth, with many small craters but no evidence of large impacts.

Question 80

What features dominate the surface of Callisto, one of Jupiter's satellites?

A)volcanoes, lava lakes, and sulfur dioxide frost
B)cracks, streaks, and very few craters in an otherwise smooth, icy surface
C)craters, densely spread over the entire surface
D)old, dark, and highly cratered polygons separated by younger, lighter, grooved terrain