Final Exam Geol

The most volcanically active body in the solar system is ______________. A. Jupiter B. Enceladus C. Europa D. Earth E. Io

E Io is the most actively volcanic body in the Solar System. This is evidenced by the fact that the spacecraft Voyager identified 11 volcanoes that had experienced recent volcanic activity. The chances of a spacecraft passing Earth and observing an erupting volcano are slim

Compared to Jupiter, Saturn has a yellowish tint. What gives it this color? A. Sulfur in the clouds B. Methane in the atmosphere C. Metallic hydrogen in the interior D. Molecular hydrogen in the atmosphere E. Crystals of ammonia ice in the clouds

E Like the presence of methane makes the atmosphere of Neptune greenish blue, crystals of ammonia ice in Saturn's clouds give Saturn its yellowish color.

PHOTO - What do the features in this image imply about the geologic history of Titan? A. It has an ancient surface. B. Glaciers of moving nitrogen ice have carved intricate channels. C. Mountains formed by north-south contraction. D. Landslides have shaped the surface on a large and small scale. E. Rivers of liquid have flowed across the surface and eroded it. F. Huge floods of lava drained across its surface.

E The dendritic pattern of this feature suggests the flowing of liquids in the form of rivers. These dendritic patterns are very similar to those seen in rivers on Earth.

The only satellite of Jupiter or Saturn known to have a substantial atmosphere is _________________. A. Ganymede B. Triton C. Io D. Rhea E. Titan

E rich in nitrogen.

Which statement is an accurate general history of cratering on a planet? A. early heavy cratering with declining intensity to the present B. initially light cratering, then intense bombardment, then light cratering to the present C. initially light cratering with increasing intensity to the present D. approximately constant rate of cratering

A

PHOTO - This set of photographs shows various landscapes on Io and Europa. Which image likely provides evidence that Io is still volcanically active?

A The lobate lava flows spreading out from a common location as seen in A show Io is still volcanically active.

What is the evidence that Ganymede and Callisto have more ice in their interiors than Io and Europa do? A. Ganymede and Callisto have lower densities. B. Ganymede and Callisto have large magnetic fields. C. Ganymede and Callisto have fewer impact craters because ice is so weak. D. Ganymede and Callisto have river channels formed when ice melted during impact.

A As we have run into many times in this class, different materials have different densities. This fact helps us determine what planetary bodies are made of. If they are dense, they have rocky and metal material. If they body has a low density there is a lot of ice. Because Ganymeade and Callisto have lower densities than Io and Europa we can conclude Ganymeade and Callisto have more ice than the other Galilean moons.

PHOTO - Which of these close up views is an image of part of Europa?

A Europa has large fractures and polygons of ice, while Io has bright yellow and orange colors with volcanic features

The grooved terrain of Ganymede _______________. A. is younger than its cratered terrain B. is older than the cratered terrain C. forms only a small part of Ganymede's surface. D. developed as Earth-style plate tectonics developed

A Impact crater frequency shows the bright and grooved terrain is younger than the older, dark, cratered terrain. As seen from the global image of Ganymeade, the bright and grooved terrain is not restricted to a small area on the moon, but makes up a significant portion of it. Though the bright and grooved terrain may have some similarities to plate tectonics on Earth, the development process is not the same as plate tectonics. The grooved terrain formed as Ganymeade expanded as it froze, creating cracks for magma of water to extrude, and then fracture as expansion continued.

Both Neptune and Uranus have magnetic fields that ___________________. A. are tilted with respect to the axis of rotation B. are stronger than Jupiter's C. produced by convection of molten iron deep inside them D. have heated their satellites to the point of melting

A Like Uranus, Neptune's magnetic field is weak and at an angle to the axis of rotation. Are both of these planets in the middle of pole reversal? Or is there something else going on? Both of the planets being gas giants, they do not have a molten iron core to produce a magnetic field. And magnetic fields do not produce heat.

On Ganymede, grooved terrain formed by which process? A. Tectonic disruption of heavily cratered terrain. B. Impact cratering. C. Hot spot volcanism. D. Planetary contraction.

A The grooved terrain formed by expansion of Ganymeade, causing rifts and grabens to develop within the cratered terrain, breaking up the previous crust. These rifts and grabens that formed subsequently filled with cryomagma (water magma) that then fractured. However, the grooved terrain began to form by extensional tectonics.

SAME PHOTO - What is the origin of the features identified in the picture of Enceladus A. icy volcanism and tidal heating B. impact melting C. collision with a passing comet D. heat released by radioactive decay of K, U, and Th

A The observed features are icy volcanoes. They cannot be a result of a comet impact, or impact melting because they do not have the structures of impacts. Nor can the heat be formed by radioactive decay, because Enceladus would not have many radioactive elements to begin with, and its supply would be exhausted by now. The only logical source of heat for Enceladus and the production of icy volcanoes is tidal heating. The same process that keeps Io warm and volcanically active.

The particles in the rings of Uranus are ______________________. A. dark and probably composed of darkened methane ice B. bright like the ice particles in the rings of Saturn C. dark like the ice particles in the rings of Saturn D. orbiting the planet outside the Roche limit.

A The particles that make up the rings of Uranus are really dark, some of the darkest objects every observed in the Solar System colored by decomposition of methane into carbon-rich residues.

How did the polygonal shapes on Pluto's Sputnik Planum form? An image of Pluto's Sputnik Planum. A. By convection of ice below a rigid upper layer. B. By the flow of glacial ice from highlands to lowlands. C. By tectonic compression of the region to form reverse faults. D. By tectonic extension of the region to form normal faults E. By shrinkage of the ice layer that fills an old impact crater.

A The shapes of the polygonal shapes within Sputnik Planitia and modelling show these cells form by convection of the basin's ice. The cell margins are the troughs and the downwelling section of the convection cell, while the center is the upward part of the convection cell.

Why does Titan have an atmosphere rich in nitrogen and methane while the Galilean satellites of Jupiter lack atmospheres? A. Titan formed farther from the Sun where ammonia and methane ice were stable in the ancient accretion disk. B. Titan is big enough to have trapped nitrogen from the solar nebula. C. The Galilean satellites never became warm enough to out gas atmospheres. D. The galilean satellites of Jupiter once had thick, nitrogen-rich atmospheres, but they were swept away by Jupiter's intense magnetic field.

A Titan formed in a location in the Solar Nebula that allowed ammonia and methane to condense as ices. The sublimation and disassociation of these molecules led to the development of an atmosphere. The galilean satellites do not have atmospheres because they condensed in a hot enough region (near Jupiter) for these volatile ices to develop.

Titan's atmosphere is rich in nitrogen (N2) and _____________. A. methane (CH4) B. carbon dioxide (CO2) C. has as much oxygen (O2) as the Earth's atmosphere D. Ammonia (NH3)

A Titan's atmosphere, in addition to nitrogen, has approximately 10% methane. The only reason there is not more methane in the atmosphere is because methane is stable on the surface in liquid form.

In what way is the orbit of Triton distinctive? A. It is retrograde. B. Its spin axis is tilted almost 90 degrees so that it rolls like a ball around Neptune. C. It is highly elliptical. D. It is not tidally locked.

A Unlike almost all of the moons in the solar system, Triton revolves around Neptune in the opposite direction of the planet's spin (retrograde orbit).

Would you expect to find young basaltic lavas at the surface of Callisto? Why? (Select all that apply.) A. No, because it is too cold. B. No, because it does not have silicates near the surface that could melt. C. Yes, Callisto is strongly tidally heated to create magma. D. Yes, large areas of dark, smooth plains are evidence that there are young lavas on Callisto.

A & B To have basaltic magmas form on a planetary body the body needs to be warm enough and have the materials that will form basalt when they melt. Ganymede is too old to have enough heat to melt such materials and it is mostly made of water ice, when this melts if forms water not basalt. So we do not have the heat or rocks to form basalt on Ganymede.

The Roche limit _________________________. (Select all that apply.) A. is produced by tidal interaction between two planetary bodies B. changes with the distance between two planetary bodies C. governs the distance within which orbiting materials will not accrete together D. is the attention span of students during a slide show

A & C The Roche Limit is the distance from a planet that when closer than, the tidal forces exerted on the planetary body grow to large and break the body into fragments.This distance is determined by the large planet (Jupiter, Saturn, etc.) and is a hypothesis on how the rings of the outer planets are created.

What is evidence that many of the outer moons of Saturn are captured rather than formed in orbit around Saturn? (Choose all that apply.) A. Many of them have highly inclined orbits. B. These outer moons are rocky and must have formed in the inner solar system before moving outward and being captured by Saturn. C. They are so big they could not have formed near Saturn which would have melted them. D. Many have retrograde orbits around Saturn.

A & D Satellites that form with the planet orbit in the same direction as the planet rotates and revolves and along the equatorial plane of the planet. Captured satellites can have very different orbits than this and also very elliptical orbits. The physical characteristics of a captured satellite depend on what direction the object was moving.

No Photo Needed These are images of two of Neptune's moons. In the photos, both are about the same size; in reality, one has a much larger diameter. Which one is larger? Triton and Proteus

A - triton We can tell Triton is actually larger because it is more spherical, the larger a planetary body gets the more spherical it becomes as its gravitational force overcomes the strength of the rock.

Why are the planetary bodies of the inner solar system different in composition from those of the outer solar system? (Select all that apply.) A. The planets formed in a thermal gradient around the ancient Sun. B. High-temperature solids could form near the ancient Sun. C. Low-temperature solids (ices) could only form near the Sun because pressure was higher there. D. Large icy cores attracted hydrogen and helium from the nebula. E. Dense objects were attracted more to the Sun and less dense ones moved outward.

A, B & D

In what way is Io similar to Earth's Moon? (Select all that apply.) A. They are about the same size. B. Both are tidally locked with one face pointed toward their host planet. C. Both have active volcanoes. D. Both have heavily cratered surfaces. E. They have about the same density.

A, B & E The easiest way to answer this question is to think "what is the major difference between the Moon and Io?". The answer to this question is Io is still geologically active while the Moon is geologically dead. This is because Io experiences tidal forces with Jupiter that keeps Io warm. This results in Io having active volcanism that buries impact craters. So we would not mark D and E because only the Moon is heavily cratered and only Io has active volcanoes.

Why aren't running water and erosion important geologic agents on all planets? (Select all that apply.)An image of the surface of Mars. A. Some planets lack solid surfaces. B. Some planets are too cold. C. Some planets have the wrong composition for water to exist. D. Some planets are too hot.

A, B, C & D

Which of the following are important components of a comet? (Select all that apply.) A. Water ice B. Silicate Materials like Olivine C. Methane D. Ammonia E. Carbon dioxide and carbon monoxide

A, B, C, D & E (All that apply) As described in figure 14.2, comets contain water ice, methane, ammonia, carbon dioxide/monoxide, and rocky material (meaning silicates).

What are the principal differences between Titan and the other satellites of Saturn? (Select all that apply.) A. Titan is the the biggest moon of Saturn. B. Titan is the only moon that has a young surface with few impact craters C. Titan has liquids that flow and pond on its surface. D. The small size of Titan compared to the others is an important feature. E. Titan is the only moon with dunes.

A, C & E Titan is the largest moon of Saturn's. Because of its atmosphere, Titan can have liquids stable on its surface, unlike any of the other moons. This dense atmosphere also allows winds that are strong enough to pick up sediment and deposit them in dunes. Most of the unique features of Titan are related to its atmosphere.

Which statements are true for the Kuiper belt? (Select all that apply.) A. It contains many small icy objects in orbit around the Sun. B. It is another name for the asteroid belt. C. It extends halfway to the nearest star. D. The orbits formed a flattened disk in the outer solar system. E. Pluto is one of the bodies in the Kuiper belt. F. It is a semi-spherical cloud of orbiting bodies with highly inclined orbits.

A, D & E The Kuiper Belt is a region beyond Neptune's orbit (30 to 50 AU) that is similar to the Asteroid Belt in many ways however, there are important differences between the two. Like the Asteroid Belt, the Kuiper Belt of leftover debris from the Solar Nebula that did not accrete into a planet. Instead of asteroids rich in rock and metals, Kuiper Belt Objects are rich in the volatile ices of water, nitrogen, methane, ammonia, and carbon monoxide. Pluto is one of these objects.

In what way is the magnetic field of Uranus distinctive? Choose all that apply. A. It has an unexpected orientation B. It is tilted compared to the spin axis C. It is irregular and may be experiencing a reversal. D. It is created by convection in its iron core. E. It is the strongest in the solar system

A,B & C Every magnetic field in the Solar System is oriented in the same direction as the axis of the planet, except for Uranus' which, is tilted 60 degrees with respect to the planet's axial tilt. Perhaps this abnormal tilt is a result of a magnetic field reversal on Uranus.

Which of the following Earth-like features have been identified on Titan? (Select all that apply.) A. Eolian dunes B. River channels C. Lakes or small seas D. A system of tectonics involving the large scale movement of lithospheric plates E. A nitrogen-rich atmosphere F. Glaciers of flowing ice G. Linear ranges formed by contraction

All except D - lithospheric plates Surprisingly, Titan is very similar to the Earth and have many similar features. Out of this list, the only features we do not see on Titan are plate tectonics (only found on Earth) and continental glaciers. Like Earth, Titan has a nitrogen-rich atmosphere, dunes and rivers (though of different composition than Earth's), and mountain ranges formed by contraction. While the details of these features are different on Titan than Earth, the physical aspects are very similar.

As a dense particle in a planet moves toward the core, the loss of gravitational potential energy is converted to _________ energy. A. chemical B. thermal (heat) C. nuclear D. solar

B

In what way is Earth's atmosphere unique among the moons and planets? A. It has a nitrogen-rich (N2) atmosphere. B. It is rich in oxygen (O2). C. It is rich in carbon dioxide (CO2) because of animal life. D. It is rich in carbon dioxide (CO2) because of plant life. E. It has clouds and storms.

B

Jupiter is different from the terrestrial planets in what important way? A. It shows atmospheric perturbations. B. It radiates more energy than it receives from the Sun. C. It is denser. D. It has a rocky surface. E. None of the above.

B

The icy layers of Jupiter's satellites increase in thickness as one moves from Europa to Callisto because ____________________. (Select all that apply.) A. the outer satellites orbit farther from the Sun B. they accreted in a thermal gradient centered around Jupiter C. the larger satellites retained more of there accretionary heat D. the inner satellites didn't out gas as much as the outer satellites

B Think of the Jupiter system like a mini Solar System and Jupiter like the Sun. Like the Solar Nebula there is a thermal gradient of high temperatures near Jupiter and lower temperatures farther from Jupiter. So near the planet we will condense refractory materials such as silicates and iron, and far from Jupiter we will condense a lot of ice when compared to silicates. So moons near Jupiter will be rich in silicates and the far moons will be enriched in water ice. For A we know that all of Jupiter's satellites are about the same distance from the Sun as Jupiter, so this could not be the reason for compositional variation among the moons. For C, even though a larger body will cool more slowly than a smaller body, the composition of the moon depends on where it is (location wise) in the thermal gradient. If it was in a location with a lot of ice, the moon will have a lot of ice regardless of if it is large or not. D, there is not much outgassing for moons. We don't see any atmospheres on these moons and outgassing does not change the composition of the moon.

Why was it surprising to discover that Enceladus had the features you just identified? A. It is composed mostly of water ice. B. Because it is so small, young surfaces were not expected. It should have cooled long ago. C. It is so close to Saturn one would expect many craters. D. It lies so far from Saturn.

B Enceladus is small (like Mimas), and based on size, it should be geologically dead and saturated with craters, just like Mimas and even our Moon. But since there is young terrain, we know something more is going on here.

PHOTO - This diagram shows the layered structure of Jupiter. Which letter labels the zone that consists of metallic hydrogen?

B From the core outward we have a core of rock and ice, surround by a layer of water ice. Surrounding the water ice is a layer of metallic hydrogen with an atmosphere of molecular hydrogen. Layer B is the metallic hydrogen layer.

PHOTO - Which letter on this image of Ariel's surface labels an area that has evidence for late expansion and possible volcanism?

B Grabens are the main evidence for expansion of a moon. the letter B is the only letter in a graben making it the correct answer.

PHOTO - Which letter on this image of Triton labels the youngest area of icy volcanism?

B Icy volcanism, like basaltic volcanism, covers the surface making it smooth. Just like the area labelled B.

Why is Jupiter so much larger than all of the terrestrial planets combined? A. It radiates a significant amount of energy like the Sun. B. It formed in the outer solar system where water ice was stable. C. It has low density. D. It has a large gravitational attraction.

B Jupiter was able to get much larger than the terrestrial planets because there was more material to accrete from at Jupiter's location. This is a result of water ice becoming stable here. There was A LOT of water in the Solar Nebula, but it could not condense into a solid state until the water is cold enough (far enough away from the Sun). Jupiter grew large because of the presence of water ice, this in turn allowed Jupiter to have a strong gravitational attraction that allowed Jupiter to hold onto the hydrogen and helium from the Solar Nebula, leading to Jupiter's very low density.

The age of the surface of Europa is like which of the satellites of Jupiter? A. Ganymede B. Io C. Amalthea D. Callisto

B Like Io, Europa has no craters indicating a similar surface age. The other moons have many craters.

What is the most likely explanation for Saturn's magnetic field? A. The magnetic field forms like Earth's—in a convecting core of molten iron. B. The magnetic field forms by convection in a shell of metallic hydrogen. C. The magnetic field forms by convcetion in the core of rock and ice driven by the great pressure of Saturn's interior. D. Saturn has no magnetic field. It isn't spinning fast enough. E. Saturn has no magnetic field. It has the wrong composition.

B Like Jupiter, Saturn does not have a iron core to generate a magnetic field in, but we know Saturn does have a magnetic field. The presence of this field can be explained by the same mechanism as we discussed for Jupiter. Convection in a metallic hydrogen shell.

How did Pluto's Sputnik Planum form? A. A supervolcano eruption filled a subsided basin with pyroclastic material. B. A large impact basin was filled with weak nitrogen ice. C. A steam explosion excavated a crater which then filled with water ice. D. Planetary contraction pulled the center of the basin downward

B Like many large basins in the Solar System (Imbrium Basin or Caloris Basin) Sputnik Planitia is suspected to have formed by a large impact that occurred early in Pluto's history. We know Pluto does not have the right composition to form a pyroclastic super volcano, nor is there a way to get water ice to turn into steam at Pluto's temperature, and we know planetary contraction does not form basins, but does form thrust faults.

Which of the Galilean satellites of Jupiter has the most heavily cratered surface. A. Io B. Callisto C. Europa D. Ganymede

B One way to answer this question is to remember that Callisto is the most heavily cratered, but you can also reason it out if you remember the order of the moons from closest to Jupiter (Io) to furthest (Callisto). Since Callisto formed the furthest from Jupiter, it has less silicate material and more ice than the other moons. This means Callisto will have less radioactive heat and will completely cool faster than the other moons and not be able to resurface. This would leave a old and heavily cratered surface.

PHOTO - What do the arrows in this image show? An image of a planetary body's surface with red arrows drawn on top of it. A. The directions of lava flow in a volcanic plain. B. Glacial flow directions C. Impact ejecta movement D. Flash flood deposits.

B Pluto's surface is rich in nitrogen ice that has the ability to flow at the conditions found on Pluto. These arrows indicate the direction of flowing, glacial nitrogen ice. There is no liquid to create flash flood deposits, impact ejecta deposits happen instantaneously and would not be going on currently. Nor can these features be lava flows, there are no volcanic edifices near this location (cryovolcanoes included).

The Oort cloud _____________________. A. is another name for the ancient solar nebula B. contains the orbits of comets in the outer part of the solar system C. is not visible outside the orbit of Mars D. contains material ejected from the Sun that condenses to make icy comets

B The Oort cloud has never been directly observed, but is inferred from the highly elliptical orbits not within the ecliptic of comets. These orbits indicate a "cloud" of comets surrounds the solar system 1/10th of the way to the nearest star that is the source of many comets.

Why are comets thought to have originated in a different part of the solar nebula than asteroids? A. Because they are much smaller bodies. B. Because they are composed mostly of ices. C. Because many are associated with ring systems of the outer planets. D. Because very few occur in the solar system.

B The composition of planetary bodies is a good indicator of location of formation. Asteroids are rich in silicates and metals while comets are ice rich. These different compositions indicate comets formed in a different location than asteroids, and the ice rich composition suggests the comets formed in the outer solar system. Comets are rarely seen because they originate from far out in the solar system, very few make the long journey into the inner solar system.

Differences in the appearance of multiring basins on the Moon with those developed on Callisto are thought to be a result of which of the following? A. The volcanic origin of Callisto's basins. B. The difference in the behavior of ice and silicates when impacted. C. The lack of the differentiation of Callisto. D. Global contraction on Callisto, but not on the other bodies.

B The difference between the multiring basins on the Moon and Valhalla stem from the different materials found on the surface on each of these satellites. The Moon is made of silicate rock while Callisto is made of water ice. These two materials have different physical properties from each other. This can cause differences in structures to occur from similar processes.

The last 2 or 3 billion years of the histories of the small inner planets (like the Moon and Mercury) are dominated by contraction, whereas the late histories of the small icy satellites of Saturn and Uranus are dominated by expansion like that evidenced in Ariel. Why? A. The outer planet satellites have warmed and expanded over that time. B. The outer planet satellites have a lot of water ice that expands as it freezes. C. The outer planet moons are so small that gravity is not strong and they expand as a result. D. The outer planet satellites were hit by many more large impacts and these have fractured them.

B The difference in composition between terrestrial bodies and ice-rich bodies is the reason. As silicates and metals freeze they shrink and become more dense. As water freezes it expands and becomes less dense.

How are the rings of Jupiter related to the small moons Adrastea and Metis? A. The magnetic fields of tiny Adrastea and Metis shepherd small chunks of ice into a narrow ring. B. Collisions at the surface of these bodies may send showers of small particles spiraling inward to Jupiter. C. Geysers of liquid water spew from the surface, freeze into droplets of ice, and go in orbit around Jupiter.

B The moons Adrastea and Metis are so close to Jupiter's rings that it is suspected, impacts into these moons can send material towards Jupiter, some of which can be trapped in the ring of Jupiter. Perhaps this process replenishes Jupiter's ring enough that the ring never completely disappears.

In what way are the icy moons of Uranus different from those of Saturn? A. lower abundance of impact craters B. slightly higher densities C. uniformly larger sizes D. all have methane atmospheres

B The moons of Uranus are about the size of Saturn's intermediately sized moons. Like Saturn's moons, the moons of Uranus are made of rock and ice. However, these moons may have more rock than Saturn's as shown by higher densities of Uranus' moons.

The tail of a comet __________________. A. is a permanent feature B. develops temporarily when the comet enters the inner solar system C. develops temporarily when the comet enters the outer solar system in an attempt to slow heat loss D. develops temporarily as material vaporizes when the comet passes through a planet's atmosphere

B The tails of comets are temporary, only happening when the comet gets near enough to the Sun (within the inner solar system) that the ices begin to vaporize, forming the tail

Which of the following is true about Saturn's rings? A. They are a series of solid disks spinning around Saturn like a hula hoop. B. The rings are composed of many small particles of water ice in orbit around Saturn. C. The rings have the same composition and brightness as the rings of Jupiter. D. Saturn is the only planet with rings in our solar system.

B Though the rings of Saturn may appear as solid disks surrounding the planet, and are in fact, made of billions of small chunks of ice that orbit Saturn.

In the early 1980's, some planetary scientists suggested that Triton has a sea of liquid nitrogen. Voyager 2 showed that _____________________________. A. this sea is about 100 m deep B. Triton is too cold for liquid nitrogen C. Triton is too warm for liquid nitrogen D. Triton has no nitrogen

B Triton is too cold for nitrogen to exist in its liquid state.

In contrast to Jupiter, Uranus and Neptune are thought to ________________________. A. have narrow ring systems B. have water ice in their interiors. C. be rocky bodies composed mostly of silicates D. have captured satellites which formed elsewhere in the solar system

B While the interior of Jupiter has water ice, it has a much thicker layer and is dominated by different forms of hydrogen (metallic and molecular). Neptune does not have these hydrogen layers and instead, the interior is dominated by water ice.

Complete this sentence. Some of the satellites of Saturn ____________________. (Select all that apply.) A. are composed of materials that melt at high temperatures explaining the abundance of craters on all of their surfaces B. orbit closer to the planet than its famous rings C. also orbit Jupiter D. Have equatorial ridges formed by accumulation of ring materials

B & D

When comparing Jupiter and Saturn, which of the following is correct? (Select all that apply.) A. Jupiter has no rings. B. Jupiter is denser. C. Jupiter is smaller. D. Jupiter has more large satellites (those larger than the moon).

B & D Saturn has a lower density than Jupiter and has more satellites larger than 100 km in diameter than any other planet. Saturn is the second largest planet (behind Jupiter) and has more pronounced rings than Jupiter.

In which ways is the Oort cloud different than the Kuiper belt? (Select all that apply.) A. The Oort cloud is nearer the Sun than most of the Kuiper belt. B. The Oort cloud is spherical, not disk-shaped. C. The Oort cloud is disk-shaped, not spherical. D. Most long period comets come from the Oort cloud. E. The bodies in the Oort cloud are much richer in silicate minerals than those in the Kuiper belt.

B & D The Oort Cloud is spherical while the Kuiper Belt is planar and in the plane of the ecliptic. The Oort Cloud is also the source of most comets while the Kuiper Belt is home to icy bodies like Pluto

Triton, because of its small size and frigid surface, was thought to be an unlikely spot for recent geologic activity. What did Voyager 2 reveal? (Select all that apply.) A. This was true. B. Triton has many young surfaces and active "volcanic" vents. C. Triton has a dark surface ruptured by volcanic vents. D. Triton was probably heated by tidal activity.

B & D Voyager 2 showed Triton is geologically complex, with young and old terrains, and large, smooth plains of cryovolcanically deposited material.

What are some important characteristics of the atmosphere of Jupiter? (Select all that apply.) A. Jupiter's atmosphere formed by outgassing of solids in its interior. B. The clouds are made of ices of ammonia (NH3) and water. C. The main gases in the atmosphere are ammonia and methane D. Jupiter's atmosphere formed by trapping nebula gas on to a large icy core. E. It is poor in carbon dioxide, unlike Mars.

B, D & E Jupiter's atmosphere is mostly composed of the gases hydrogen and helium, however there are significant amounts of the ices ammonia and water. Unlike the terrestrial planets, the atmosphere of Jupiter did not form by outgassing of the planet, but by collapse of the nebular gases onto Jupiter's large rocky-ice core. And unlike Mars and Venus, Jupiter does not have any carbon dioxide in its atmosphere.

What is the most important control on a planet's present level of geologic activity (especially volcanism and tectonism)?An image of the surface of a planetary body that shows evidence of geologic activity. A. Its distance from the Sun. B. Its surface temperature. C. The thickness of its lithosphere. D. The composition of its atmosphere.

C

Why are many of Saturn's moons shaped like this one (Phoebe) (no pic needed), instead of being essentially spherical? A. They lie too far from the Sun to become spherical—a feature caused by more intense solar winds near the Sun B. These satellites lie too far from Saturn to be affected by its intense magnetic field. C. The size and hence the gravity field are not large enough to deform the irregular bodies into near spherical shapes. D. The irregular satellites have solid surfaces unlike the gaseous, but spherical moons.

C As discussed early in the semester, to become spherical a planetary body needs to be large enough to have enough gravity to overcome the strength of the materials it accreted from.

Which of the following is a common process that occurred during the evolution of the satellites of Uranus? A. fluvial erosion by running water B. eolian erosion by strong, cold winds C. cracking as they expanded late in their histories D. the eruption of basaltic (silicate) lavas E. accretion from dense rocky materials

C As these ice-rich moons cool and the liquid water freezes, the water ice expands, and creates large fractures that cut across the moons surfaces. There is no running water, or atmosphere to cause erosion, and cool nature/composition of the moon does not allow basalt to form.

Where does Jupiter's large magnetic field come from? A. It develops like Earth's field when convection happens in a layer of molten iron deep inside. B. All planets that spin have magnetic fields. C. Convection in a layer of ionized hydrogen may create the magnetic field. D. It is induced by the orbital motions of its moons and the ring system.

C As we have discussed previously, movement of a charged particles can produce a magnetic field. With the terrestrial planets a magnetic field is produced by convective motion of molten iron in the planets outer core. Since Jupiter does not have the same internal structure there must be a slightly different way the magnetic field develops. It occurs by convective motion of charged hydrogen in the metallic hydrogen layer of Jupiter.

The surface of Io is thought to be less than a million years old because ________________. A. it is internally differentiated B. volcanoes have been discovered on its surface C. it has no impact craters D. it is too close to Jupiter

C As we have seen numerous times throughout the course of this class, the crater density on a planetary body reflects how old the surface is. Since Io has no impact craters, we can conclude the surface is very young.

The tall mountains on Pluto are composed of what kind of ice? A. Methane B. Nitrogen C. Water D. Carbon dioxide E. Ammonia

C At the surface temperatures of Pluto, the volatile ices listed above are too weak to support topography. These ices will flow under their own weight. On the other hand, water ice is incredibly strong, perhaps as strong as silicate rock at these low temperatures, and can build up high topography (4-5 km).

PHOTO - Which of the letters on this image of Titan's dunes labels a feature that is the strongest evidence for the movement of sand in the dunes?

C C shows linear dunes that are very indicative of movement of sand particles. B and A are both hills with no dunes on their surfaces.

The nucleus of a comet __________________. A. is small, bright, and composed of ices B. is large, bright, and composed of vapors and dust jetted from the core C. is small and dark D. has never been seen

C Comet Halley is a good, representative sample of comets. Like comet Halley, the nucleus of comets is dark. The reason why is shown in Figure 14.4, the surface of a comet's nucleus is coated in a dark, carbonaceous residue.

Comets glow in the night sky because __________________________.An image of a comet in space. A. they produce energy by cold fusion B. they produce energy by thermonuclear fusion C. they reflect the light from the Sun D. the coma consists of ionized gasses that interact with the Sun's magnetic field.

C Comets do not produce energy on their own, however, they do glow (as seen in Figure 14.2). Comets glow because of the light reflected from Sun.

What is the most abundant of the gases comprising Saturn?An image of Saturn. A. nitrogen B. helium C. hydrogen D. ammonia

C Like Jupiter.

PHOTO - Which letter in this image of Ganymede labels an area of grooved terrain?

C Links to an external site. Ganymeade is made up of two primary terrains: the dark cratered terrain and the bright, grooved terrain. C is the grooved terrain, we can determine this by seeing grooves within bright bands that cuts across darker terrain (A).

PHOTO - Enceladus (500 km across) and Mimas (400 km across) are both small, icy moons with about the same diameter. Enceladus is shown here. Which letter labels a feature that makes Enceladus so different from Mimas?

C Mimas is a geologically dead moon and saturated with craters. While Enceladus does have some heavily cratered terrain, it also has younger terrain shown at C.

The composition of the surface of Ganymede is most like which of the other satellites of Jupiter? A. Amalthea B. Io C. Europa D. Triton

C Take a look at the summary table 9.1 as well. There are a couple parts to this question. First is to identify which choices are moons of Jupiter. We know Triton is not a moon of Jupiter (it is a moon of Neptune) so we can cross out that choice. Now we have to remember what the surface of Ganymede is made of. the low density of the moon indicates it will have a lot of water ice, and most low density planetary objects have a surface made of water ice. We know Io is fairly dense and volcanically active, indicating this moon has a lot of silicate material. Europa has a low density and fractures that are consistent with an expanding ice shell. We can conclude from this that Europa has a surface of water ice, just like Ganymede.

Where is Saturn's Roche limit for small icy bodies in orbit around it? A. Near the orbit of Tethys. B. In the Cassini Division. C. Near the outer edge of the rings. D. Near the inner edge of the rings. E. Just beyond the orbit of the outermost satellite.

C The Roche Limit is near the outer edge of the rings. Closer to the planet than this, Saturn has the rings of broken fragments. Beyond this distance, Saturn's satellites are whole.

The banding of Jupiter's atmosphere is probably related to which of the following? A. Jupiter's atmosphere shows no banding. B. Reflection of the surface features. C. Turbulent winds in the atmosphere of this rapidly spinning planet. D. The composition of the atmosphere.

C The bands of Jupiter (called "zones") are formed by turbulent winds in the atmosphere similar to the cyclones and anticyclones of Earth (rising and sinking gas). By looking at any image of Jupiter, we know the planet is indeed banded. Since Jupiter does not have a true surface and does have an incredibly thick atmosphere, we can deduce the bands are not a reflection of surface features.

Pluto's atmosphere is tenuous and temporary, but what are it's major constituents? A. Hydrogen and helium inherited from the solar system. B. Carbon dioxide and oxygen released by volcanism as a secondary atmosphere. C. Nitrogen and methane that sublime from the most volatile ices on its surface. D. Water vapor that sublimes from its thick water ice crust.

C The composition of Pluto's surface is reflected in the composition of the body's atmosphere. Pluto's surface ices of nitrogen and methane are so volatile and Pluto's surface temperature is so close to the ices sublimation temperature that small fluctuations in solar insolation can cause these ices to sublime into the atmosphere. Pluto is too small to have, gravitationally, held on to the hydrogen and helium of the Solar Nebula. Since Pluto is not a terrestrial planet, there was no volcanic outgassing carbon dioxide and no life to form free oxygen. While Pluto does have a thick water ice lithosphere, Pluto's surface temperature is too cold to allow sublimation of water ice.

Saturn is the most similar in composition and internal structure to which of the planets below. A. Mercury B. Mars C. Jupiter D. Neptune

C The composition of Saturn is incredibly rich in hydrogen and helium, just like Jupiter. Mars and Mercury are terrestrial planets rich in silicates and metals. Neptune does have hydrogen and helium but it also has a lot of methane, which Saturn and Jupiter do not have.

What is the evidence that the moons of Saturn are generally icy? A. They orbit near the icy rings of Saturn so they must also be icy. B. Their most common mineral is light-colored feldspar. C. They have densities less than 2.0 g/cm3. D. They are volcanically active like Io.

C The density of a planetary body is indicative of its composition. High density suggests a lot of metal and silicates, low density suggests a lot of ice. Since we have low densities for Saturn's moons we can conclude they are icy.

What causes the Cassini Division, the 400 km wide break in the rings of Saturn?An image of Saturn's rings, showing the Cassini Division. A. The tidal disruption of small bodies at this distance. B. The low temperature at this distance. C. Orbital resonance of the ring particles with the larger satellites. D. The presence of a ring shepherd in the gap.

C The gap appears to be the result of Mimas 2:1 resonance with the division. Clearing out the division by pulling the objects away from this location. Tidal disruptions would cause fragments to form here, and therefore is not correct. Perhaps, there are larger particles that sweep up smaller particles. But planetary scientists have not seen evidence for this.

PHOTO - The dark reddish regions on Charon's north pole result from what process?An image of Charon's north pole. A. Impact of icy cometary objects with distinctive compositions. B. Landslides. C. Methane from Pluto condenses at Charon's poles. D. Deposits from geysers like those on Enceladus.

C The reddish material on Charon's north pole is compositionally similar to that of tholins and can be produced by photochemical reactions of methane. This methane is sourced from Pluto as it escapes the atmosphere. The methane can make its way to Charon and become deposited on the north pole during a Charon winter. As the pole moves into the sunlight, the methane reacts with the light and becomes refractory.

Which of the following planetary bodies has the oldest surface? A. Venus B. Mars C. Mercury D. Earth E. the Moon

E

What is the most important source of energy that drives the circulation of Saturn's atmosphere? A. solar heating B. rotation C. heat released from the interior D. large storms in the outer atmosphere E. the large magnetic field

C Unlike the terrestrial planets, the motions within Saturn's atmosphere are caused by heat rising from the planet's interior. Perhaps, as a result of liquid hydrogen raining out from the atmosphere.

Why is it appropriate to call Uranus the "oddball" planet? A. It lacks a ring system. B. It has a density similar to terrestrial planets in spite of its gas-rich composition. C. Its spin axis is tipped from vertical by over 90 degrees. D. It revolves around the Sun in a retrograde direction.

C Uranus is very similar to the other gas giants. It has a faint ring system made of dark materials (making it hard to see), Uranus has a similar density, and it revolves around the Sun in the same direction. The biggest difference between Uranus and every other planet (excluding Pluto) is its extreme axial tilt (90 degrees).

How did the multiple rings of Valhalla on Callisto form? A. Collapse of a volcanic caldera. B. Domal upwarping of the lithosphere. C. Crustal breakage as impact shock waves traveled through the surface. D. Eruption of flowing ice outward from a surface fracture.

C Valhalla is a large impact structure. It has multiple rings, just like the multiring basins on the Moon (though Valhalla has many more rings). These rings form as shock waves travel through the crust after impact.

Why is Neptune blue? A. Because of the scattering of light by dust grains in its atmosphere. B. Because of reflection off an ocean of liquid water that lies just below the cloud layer. C. Because its atmosphere contains a significant proportion of methane. D. Because it has a high concentration of metallic hydrogen near the base of the clouds.

C Neptune's atmosphere because of the presence of methane, which reflects blue light and absorbs red light.

The final days of comet Shoemaker Levy 9 were marked by which of the following? (Select all that apply.) A. The formulation of a planetary nebula. B. Its tidal breakup in orbit around the Sun. C. The vaporization of all of its ice and consequent disaggregation. D. Explosions in the atmosphere of Jupiter

C & D The life of the comet Shoe Maker Levy 9 ended as it broke apart as all of its ice was vaporized and the multitude of remaining parts fell into Jupiter's atmosphere in a series of explosions.

PHOTO - arrange these images of Jupiter's satellites by their distance from Jupiter as they orbit. Place the closest satellite on the top and the farthest one on the bottom.

Closest - BCDA Io, Europa, Ganymede, Callisto

Suppose that a new planet has been discovered between Venus and Earth. It is about the size of Earth's Moon. Which of the following statements about it is probably true? A. It would be covered with a thin layer of water ice. B. It should have a very active tectonic system. C. It will have numerous active volcanoes. D. It should be intensely cratered and lack a thick atmosphere. E. It should have a thick, oxygen-rich atmosphere.

D

Which of the following is most important in keeping water a liquid on Earth? A. the size of Earth B. the biosphere C. the original composition of the planet D. the distance from the Sun

D

Which of the following are common features on the icy satellites of Saturn? A. Large shield volcanoes like those on Mars. B. Multiring impact features like those on Callisto and Ganymede. C. Integrated hydrologic systems with rivers and oceans. D. Global rifts apparently caused by expansion. E. Thick atmospheres of carbon dioxide

D A common feature of ice rich satellites are large rifts caused by extensional tectonics. This occurs because solid water takes up more volume than liquid water. So when the liquid water freezes, the planet expands forming rifts and grabens.

What is the origin of the light-colored streaks extending from the surface of comet Churyumov-Gerasimenko? A. The streaks are small volcanic eruptions like those on Io. B. The streaks are just light reflected off the surface to form rays. C. The streaks were formed as material was ejected from the surface by a small impact. D. The streaks are plumes of dust and gas ejected from the interior as the Sun heats it.

D Because comets are so small, they do not have any internal energy to produce volcanism, so these streaks are the result of a different process. As comets get near the Sun they heat up. This increase in heat, vaporizes the interior ices into gas that is released through surficial cracks and produces these streaks.

Which of the following is true about the subdued crater palimpsests on Ganymede? A. They formed as the planet froze and expanded. B. They are more abundant in the grooved terrain than in the cratered terrain. C. Palimpsests were produced by ionic deformation within the ice. D. They were produced as the icy lithosphere flowed to fill in an impact crater.

D By definition, palimpsests are remnants of old craters that have been modified by ice flow, causing the crater to be smoothed out and the topography erased. These craters are similar to ghost craters on the terrestrial planets (such as Mercury and the Moon) where basalt lava flows covered the original crater.

PHOTO - This set of photographs shows various landscapes on Io and Europa. Which image shows that the surface of Europa has been tectonically deformed?

D In image D we see large, criss-crossing fractures that are evidence of extensional tectonics.

If you were a solar system explorer in search of liquid water at or near the surface, which of the satellites of Jupiter would be most likely to have it today? A. Io B. Ganymede C. Callisto D. Europa

D It is most likely that we would find liquid water on Europa because it has a lot of water, and is close enough to Jupiter that the moon will still have significant amounts of heat from radioactive decay of silicates, allowing the moon to be warm enough to have liquid water and not be completely frozen.

Pluto is considered to be a dwarf planet by some astronomers. Why? A. Because it is not big enough to have developed a nearly spherical shape. B. Because it generates heat by nuclear fusion deep in its core. C. Because its orbit is elliptical and inclined. D. Because it has not cleared its orbital path of debris.

D The current definition of a planet can be stated as: a planet is spherical, does nut does not generate nuclear fusion, orbits the Sun, and has cleared its orbit. Images from New Horizons show Pluto is spherical and does not undergo nuclear fusion. Pluto's orbit is elliptical and inclined, but the definition of a planet does not address this concern. Pluto is not considered a planet because there is still debris in Pluto's orbit; Pluto has not cleared out its orbit.

Which of the following are major differences between Io and Europa? A. Europa is much larger than Io. B. The age of their surfaces. C. Europa is much denser than Io. D. The composition of the surface materials.

D The density of Io indicates Io is made of silicates, while the density of Europa indicates it is made of ice.

Which of the following statements is true about Europa? A. Europa has abundant craters and large impact basins. B. Europa has no water ice at its surface and is dominated by silicates. C. It is composed of ice throughout. D. It has crisscrossing stripes and fractures.

D The images of Europa show long, linear fractures that extend across the icy surface.

Jupiter is composed mainly of ____________. A. hydrogen, lithium, and sodium B. rocky silicate materials C. water ice D. hydrogen and helium

D The incredibly low density of Jupiter (1.3 g/cm3) indicates a very different composition than any of the dense, terrestrial planets. While Jupiter does have core of rock and water ice, the amount of these materials is far less than the hydrogen and helium contained in Jupiter's atmosphere.

Which letter on this image of Triton marks an area that has a composition like Earth's atmosphere?

D Triton's polar ice cap is dominated by nitrogen ice. D is this ice cap as shown in figure 12.13. Also, look for the dark streaks that are present within the ice cap.

Based on what we know today, which of the following is most like Pluto in its size, composition, and density? A. Mercury B. the Earth's Moon C. Europa D. Triton E. Neptune

D Triton, like Pluto, is small (2,700 km in diameter compared to Pluto's 2,377 km), rich in nitrogen ice, and has a water ice lithosphere and a rocky core. Mercury is much larger than Pluto and is a terrestrial planet with a silicate and metal composition. Europa and Earth's Moon are also rich in silicates and poor in ices. Neptune is a gas giant, larger than Pluto and of a different composition.

Why does the interior of Uranus appear to lack a layer of metallic hydrogen like those in Saturn and Jupiter? A. Uranus is too far from the Sun and the temperature is consequently too low. B. Uranus doesn't have enough hydrogen to make the transition to metallic state. C. The magnetic field of Uranus is too weak to make the hydrogen convert to its metallic form. D. Uranus is too small and the internal temperature and pressure are not high enough for metallic hydrogen.

D Uranus is not large enough to produce the extreme pressure needed to form a metallic hydrogen layer.

Why isn't Earth's Moon heated by tidal flexing? (Select all that apply.) A. The Moon is too far away from the Earth. B. The outer part of the Moon is too rigid to flex as a result of tidal forces. C. The tidal energy is dissipated by the rise and fall of tides in Earth's oceans. D. The orbit of the Moon is nearly circular. E. Earth only has one large moon, unlike Jupiter.

D & E To be heated by tidal flexing the moon has to have an eccentric orbit. This means at some points in the moon's orbit it is closer to the planet and other times it is far from the planet. This varies the magnitude of the gravitational pull on the moon (higher when it is near and lower when it is far). This basically massages the moon like dough in your hands. The friction of the motion creates the heat. To get an eccentric orbit, the planet has to have other large moons that pull the orbit away from being circular.

The absence of large folded mountain systems on the Moon, Mars, and Mercury is evidence that the lithospheres of these planets ___________________. A. have been highly mobile in recent times B. are younger than that of Earth C. are older than that of Earth D. have histories similar to that of Earth's E. thickened "rapidly" as these worlds cooled.

E

Is this comet near the Sun (within the orbit of Jupiter)? Yes or No Pic of Comet with a tail

Yes A comet only develops a tail when it is near the Sun. Since this comet has a tail, it has to be near the Sun.