Astronomy chaper 9

Why do the lunar highlands have many more craters than the lunar maria? a) They are on the side of the Moon away from Earth, which was hit by more impacts. b) Lava flooded the maria, hiding many craters. c) The less cratered surfaces are younger than those with more craters. d) all of the above e) B and C

e) B and C

Why do we think Mars had more volcanic activity in the past than it does today? a) Mars was bombarded with more impacts in the past, which fueled more volcanic activity. b) Mars would have been warmer in the past. c) Some meteorites from Mars come from relatively young lava. d) all of the above e) B and C

e) B and C

Which of the terrestrial worlds has the strongest magnetic field? a) the Moon b) Mercury c) Venus d) Mars e) Earth

e) Earth

Which two bodies show evidence of liquid water? a) Mercury and Venus b) Mercury and Earth c) Mercury and Earth's Moon d) Earth and Venus e) Earth and Mars

e) Earth and Mars

The three principal sources of internal heat of terrestrial planets are a) accretion, differentiation, and eruption. b) conduction, differentiation, and accretion. c) conduction, convection, and eruption. d) convection, differentiation, and eruption. e) accretion, differentiation, and radioactivity.

e) accretion, differentiation, and radioactivity.

What evidence is there for past liquid water is on Mars? a) channels that look like dry riverbeds b) eroded crater rims and erased craters c) Spirit and Opportunity rovers have found mineral evidence of water d) ice in Mar's polar caps e) all of the above

e) all of the above

Which two properties are most important in determining the surface temperature of a planet? a) composition and distance from the Sun b) internal temperature and atmosphere c) size and atmosphere d) size and chemical composition e) distance from the Sun and atmosphere

e) distance from the Sun and atmosphere

Spacecraft have landed on all the terrestrial worlds except a) Moon. b) Venus. c) Mars. d) Mercury. e) Spacecraft have landed on all of the terrestrial worlds.

e) Spacecraft have landed on all of the terrestrial worlds.

Earth is the only terrestrial planet to have experienced tectonic stresses and volcanic activity. a) True b) False

b) False

Which planetary properties control erosion? a) size b) rotation rate c) distance from the Sun d) all of the above

d) all of the above

Valles Marineris is a a) huge series of cliffs on Mercury. b) vast plain on Mars. c) large canyon on Venus. d) large valley on the Moon. e) large canyon on Mars.

e) large canyon on Mars.

Where did Earth's (interior) heat come from? a) volcanoes b) impacts as Earth was accreting c) radioactivity d) all of the above e) B and C

e) B and C

Since Venus is covered with thick clouds, a) we presume it has active volcanoes. b) we observe it with radar. c) we observe it with landers. d) all of the above e) B and C

e) B and C

How does an object's rate of cooling vary with size? a) A larger object cools more slowly than a smaller object. b) A smaller object cools more slowly than a larger object. c) Size has no effect on an object's rate of cooling.

a) A larger object cools more slowly than a smaller object.

Which of the following most likely explains why Venus does not have a strong magnetic field? a) Its rotation is too slow. b) It has too thick an atmosphere. c) It is too large. d) It is too close to the Sun. e) It does not have a metallic core

a) Its rotation is too slow.

Why does Earth have the strongest magnetic field among the terrestrial worlds? a) It is the only one that has both a partially molten metallic core and reasonably rapid rotation. b) It rotates much faster than any other terrestrial world. c) It is by far the largest terrestrial world. d) It is the only one that has a metallic core. e) It is the most volcanically active world.

a) It is the only one that has both a partially molten metallic core and reasonably rapid rotation.

About how large (on average) is an impact crater compared to the size of the impactor? a) 10 times larger b) 1,000 times larger c) the same size d) 100 times larger e) 10-20 percent larger

a) 10 times larger

What role does a planet's size play in its geological activity? a) Larger planets are more geologically active because they take longer to cool off. b) Larger planets are more geologically active because they have thicker lithospheres. c) Larger planets are less geologically active because they have thicker lithospheres. d) Larger planets are less geologically active because they have larger surface areas to radiate heat away. e) Larger planets are less geologically active because there is a greater distance between the core and the surface

a) Larger planets are more geologically active because they take longer to cool off.

Earth is the only planet in the solar system known to have plate tectonics. a) True b) False

a) True

Higher temperatures make rocks weaker. a) True b) False

a) True

Mars has virtually no magnetic field. a) True b) False

a) True

Spacecraft have landed on all of the terrestrial worlds. a) True b) False

a) True

The process in which one plate slides under another is called subduction and is marked by deep ocean trenches. a) True b) False

a) True

The strength of a rock depends on its composition, its temperature, and the surrounding pressure. a) True b) False

a) True

Very high pressures, like those found deep within planetary interiors, can compress rocks so much that they stay solid even when temperatures are high enough to melt them under ordinary conditions. a) True b) False

a) True

Based on its surface features, the most important event on Venus in the past billion years or so was _______. a) a global "repaving" that erased essentially all the surface features that had existed earlier b) the onset of mantle convection, which caused Venus's lithosphere to split into plates like those on Earth c) the eruption of a giant volcano that formed one of Venus's "continents" d) the impact of an unusually large asteroid that left a deep scar on one side of the planet

a) a global "repaving" that erased essentially all the surface features that had existed earlier

The reason that small planets tend to lose interior heat faster than larger planets is essentially the same as the reason that ________. a) a large baked potato takes longer to cool than a small baked potato b) thunderstorms tend to form on hot summer days c) gas bubbles form and rise upward in boiling water d) Earth contains more metal than the Moon

a) a large baked potato takes longer to cool than a small baked potato

The interior of Earth consists of a) a metallic core and solid rock outer shell. b) a rocky core and metallic outer shell. c) a metallic core and liquid rock outer shell. d) a liquid rocky inner core and solid rock outer shell. e) a mixture of rock and metals throughout.

a) a metallic core and solid rock outer shell.

Which of the following geological processes is most evident on the surface of a small planet? a) impact cratering b) erosion c) volcanism d) tectonics e) size does not affect the geological processes

a) impact cratering

The geological age of a planet's surface can be determined from the relative amount of a) impact craters. b) erosion features. c) volcanic features. d) tectonic features.

a) impact craters.

What is the most important factor that determines the thickness, and therefore strength, of the lithosphere? a) internal temperature b) viscosity c) composition d) pressure e) distance of planet from Sun

a) internal temperature

The cores of the terrestrial worlds are made mostly of metal because ______. a) metals sunk to the centers a long time ago when the interiors were molten throughout b) the terrestrial worlds as a whole are made mostly of metal c) over billions of years, convection gradually brought dense metals downward to the core d) the core contained lots of radioactive elements that decayed into metals

a) metals sunk to the centers a long time ago when the interiors were molten throughout

How many of the five terrestrial worlds have surfaces being constantly reshaped by plate tectonics? a) one b) two c) three or more

a) one

Which of a planet's fundamental properties has the greatest effect on its level of volcanic and tectonic activity? a) size b) distance from the Sun c) rotation rate

a) size

Which of the following best describes the geological histories of the Moon and Mercury? a) Impact cratering is the only major geological process that has affected their surfaces. b) Early in their histories, they suffered many impacts and experienced some volcanism and tectonics, but they now have little geological activity at all. c) All four geological processes were important in their early histories, but only impact cratering still reshapes their surfaces today. d) Impact cratering shaped these worlds early in their histories. Then, during the past few million years, they were reshaped by episodes of volcanism and tectonics.

b) Early in their histories, they suffered many impacts and experienced some volcanism and tectonics, but they now have little geological activity at all.

What is the longest-lasting internal heat source responsible for geological activity? a) accretion b) radioactive decay c) sunlight

b) radioactive decay

The lithosphere of a planet is the layer that consists of a) material above the crust. b) the rigid rocky material of the crust and uppermost portion of the mantle. c) the softer rocky material of the mantle. d) material between the crust and the mantle. e) the lava that comes out of volcanoes.

b) the rigid rocky material of the crust and uppermost portion of the mantle.

Choose the correct description of the conveyor-like action of plate tectonics on Earth. a) Earth's lithosphere is broken up into plates that float beneath the overlying mantle. The bottoms of the mantle's convection cells drag the tops of the plates, making them move. This movement causes spreading in some places and subduction in others. b) Earth's lithosphere is broken up into plates that float on the underlying mantle. The tops of the mantle's convection cells drag the bottoms of the plates, making them move. This movement causes spreading in some places and subduction in others. c) Earth's mantle is broken up into plates that float beneath the overlying lithosphere. The bottoms of the mantle's convection cells drag the tops of the plates, making them move. This movement causes spreading in some places and subduction in others. d) Earth's mantle is broken up into plates that float on the underlying lithosphere. The tops of the mantle's convection cells drag the bottoms of the plates, making them move. This movement causes spreading in some places and subduction in others.

b) Earth's lithosphere is broken up into plates that float on the underlying mantle. The tops of the mantle's convection cells drag the bottoms of the plates, making them move. This movement causes spreading in some places and subduction in others.

In the inner solar system, the largest surface features are found on the largest planets. a) True b) False

b) False

There is no erosion of surface features on the Moon. a) True b) False

b) False

Which internal heat source still generates heat within the terrestrial worlds today? a) Heat of accretion. b) Heat from radioactive decay. c) Heat from convection. d) Heat from differentiation

b) Heat from radioactive decay.

As a planet cools, what happens to its lithosphere? a) Nothing, except getting colder too. b) It gets thicker. c) It gets thinner. d) It rises to the surface of the planet. e) It sinks to the center of the planet.

b) It gets thicker.

Why does the Moon have a layer of powdery "soil" on its surface? a) The soil exists because the Moon accreted from powdery material after a giant impact blasted Earth. b) It's the result of gradual erosion by micrometeorites striking the Moon. c) The soil is the result of the same processes that make powdery sand on Earth. d) Volatiles escaping from the Moon's interior bubble upward and make the soil. e) Large impacts shattered lunar rock to make this soil.

b) It's the result of gradual erosion by micrometeorites striking the Moon.

Recent evidence suggests that Mars once had a global magnetic field. Assuming this is true, which of the following could explain why Mars today lacks a global magnetic field like that of Earth? a) Mars is too far from the Sun to have a global magnetic field. b) Mars's interior has cooled so much that its molten core layer no longer undergoes convection. c) The Martian core is made of rock, whereas Earth's core is made of metal. d) Mars rotates much slower than the Earth.

b) Mars's interior has cooled so much that its molten core layer no longer undergoes convection.

Who popularized the idea that there was a network of canals on Mars which carried water from the polar ice caps? a) Giovanni Schiaparelli b) Percival Lowell c) William Herschel d) H. G. Wells e) Orson Wells

b) Percival Lowell

The choices describe four hypothetical planets. Which one would you expect to have the hottest interior? (Assume the planets orbit a star just like the Sun and that they are all the same age as the planets in our solar system.) a) Size: same as Mars. Distance from Sun: same as Earth. Rotation rate: once every 18 hours. b) Size: twice as big as Earth. Distance from Sun: same as Mercury. Rotation rate: once every 6 months. c) Size: same as the Moon. Distance from Sun: same as Mars. Rotation rate: once every 10 days. d) Size: same as Venus. Distance from Sun: same as Mars. Rotation rate: once every 25 hours.

b) Size: twice as big as Earth. Distance from Sun: same as Mercury. Rotation rate: once every 6 months.

Most of the Moon's surface is densely covered with craters, but we find relatively few craters within the lunar maria. What can we conclude? a) The regions of the maria were hit by fewer impacts than the densely cratered regions. b) The maria formed after the heavy bombardment ended. c) The maria formed within the past 1 billion years. d) Erosion affects the maria more than it affects other regions of the Moon.

b) The maria formed after the heavy bombardment ended.

Why are there fewer large craters on the seafloor than on the continents? a) The oceans slow large impactors and prevent them from making craters. b) The seafloor crust is younger than the continental crust. c) Large impactors primarily strike land masses. d) The oceans erode away craters faster than erosion processes on land. e) Large impactors aim for life-forms such as dinosaurs.

b) The seafloor crust is younger than the continental crust.

Why are smaller terrestrial bodies such as Mercury or the Moon "geologically dead"? a) They don't have volcanoes. b) They cooled off faster than Earth did. c) They don't have erosion. d) They were hit by fewer meteorites than Earth. e) They are made of different materials than Earth.

b) They cooled off faster than Earth did.

Why does Mercury have large cliffs? a) They were produced by plate tectonics, much like cliffs on Earth. b) They were produced when the interior cooled and the entire planet shrank. c) They were produced by the stress of a large upwelling on one side of the planet that produced a bulge with canyons and cliffs. d) The cliffs are the rims of large impact basins.

b) They were produced when the interior cooled and the entire planet shrank.

The main process by which heat flows upward through the lithosphere is a) convection. b) conduction. c) radiation. d) accretion. e) differentiation.

b) conduction.

The inside of Earth is filled with molten lava a) true b) false

b) false

Which of the following geological processes is currently active on Mars? a) volcansim b) impact cratering c) tectonics d) all of the above e) none of the above

b) impact cratering

Do you think differentiation is likely to happen in a very small planet? a) yes b) no

b) no

Deep trenches in the ocean mark places where a) plates pull apart, leaving great rifts in the crust. b) one plate slides under another, returning older crust to the mantle. c) plates push together, creating ocean mountain chains. d) hot mantle material rises upward and spreads sideways, pushing the plates apart. e) plates slip sideways relative to one another.

b) one plate slides under another, returning older crust to the mantle.

Which of the following describes erosion? a) the disruption of a planet's surface by internal stresses b) the wearing down or building up of geological features by wind, water, ice, and other phenomena of planetary weather c) the eruption of molten rock from a planet's interior to its surface d) the excavation of bowl-shaped depressions by asteroids or comets striking a planet's surface

b) the wearing down or building up of geological features by wind, water, ice, and other phenomena of planetary weather

Why is Earth's continental crust lower in density than seafloor crust? a) Continental crust comes from Earth's inner core, whereas seafloor crust comes from the outer core. b) Continental crust is made from a low-density volcanic rock called basalt. c) Continental crust is made as the lowest-density seafloor crust melts and erupts to the surface near subduction zones. d) Continental crust comes from volcanoes, whereas seafloor crust comes from geysers.

c) Continental crust is made as the lowest-density seafloor crust melts and erupts to the surface near subduction zones.

Which of the following is an example of convection? a) Heat radiates from a planet into space. b) Heat travels from atom to atom from inside a planet to the outside. c) Hot material inside a planet rises, and cool material sinks towards the center. d) Metal conducts energy throughout Earth's core.

c) Hot material inside a planet rises, and cool material sinks towards the center.

Which of the following best describes convection? a) It is the process by which rocks sink in water. b) It is the process in which a liquid separates according to density, such as oil and water separating in a jar. c) It is the process in which warm material expands and rises while cool material contracts and falls. d) It is the process in which warm material gets even warmer and cool material gets even cooler. e) It is the process in which bubbles of gas move upward through a liquid of the same temperature.

c) It is the process in which warm material expands and rises while cool material contracts and falls.

What feature of Venusian geology is largely unexplained? a) It lacks substantial erosion. b) It has few impact craters. c) It lacks plate tectonics. d) None of the above; we understand each of these features.

c) It lacks plate tectonics.

You discover an impact crater that is 10 kilometers across. Which of the following can you conclude? a) It was created within the past 10 million years. b) It was created by the impact of an object about 100 kilometers across. c) It was created by the impact of an object about 1 kilometer across. d) It was created within the past 1 billion years. e) It was created by the impact of an object about 10 kilometers across.

c) It was created by the impact of an object about 1 kilometer across.

Which of the following most likely explains why Venus does not have a global magnetic field like Earth? a) It does not have a metallic core. b) Unlike Earth, Venus does not have a liquid outer core. c) Its rotation is too slow. d) It has too thick of an atmosphere.

c) Its rotation is too slow.

How did the lunar maria form? a) The maria are the result of gradual erosion by micrometeorites striking the Moon. b) Volatiles escaping from the Moon's interior heated and eroded the surface in the regions of the maria. c) Large impacts fractured the Moon's lithosphere, allowing lava to fill the impact basins. d) The giant impact that created the Moon left smooth areas that we call the maria. e) The early bombardment created heat that melted the lunar surface in the regions of the maria.

c) Large impacts fractured the Moon's lithosphere, allowing lava to fill the impact basins.

Which two bodies show evidence of heavy cratering? a) Mercury and Venus b) Mercury and Earth c) Mercury and Earth's Moon d) Earth and Venus e) Earth and Mars

c) Mercury and Earth's Moon

Rank the five terrestrial worlds in order of size from smallest to largest. a) Mercury, Moon, Venus, Earth, Mars b) Mercury, Venus, Earth, Moon, Mars c) Moon, Mercury, Mars, Venus, Earth d) Moon, Mercury, Venus, Earth, Mars e) Mercury, Moon, Mars, Earth, Venus

c) Moon, Mercury, Mars, Venus, Earth

Suppose we had a device that allowed us to see Earth's interior. If we looked at a typical region of the mantle, what would we see happening? a) a rapid, up and down churning of the material in the mantle b) Hot molten rock rising upward throughout the mantle and cool, solid rock falling downward. c) On human time scales, the mantle looks like solid rock, so not much would be seen. d) Dense metals falling downward and low-density rock rising upward.

c) On human time scales, the mantle looks like solid rock, so not much would be seen

What do we conclude if a planet has few impact craters of any size? a) The planet was never bombarded by asteroids or comets. b) Its atmosphere stopped impactors of all sizes. c) Other geological processes have wiped out craters.

c) Other geological processes have wiped out craters.

Which of the following is not a similarity between Mars and Earth today? a) The lengths of their days are similar. b) They both have polar ice caps. c) They both have rivers. d) They have similar amounts of land. e) They have similar axis tilts.

c) They both have rivers.

What is necessary for differentiation to occur in a planet? a) It must be made of metal and rock. b) It must be made of a mix of materials of different density. c) Material inside must be able to flow. d) all of the above e) B and C

e) B and C

Drilling into the surface, a robotic spacecraft discovers liquid water beneath the slopes of a Martian volcano. Choose the correct explanation of whether the discovery should be considered reasonable or surprising. a) This would be exciting and surprising. Heat from Martian volcanoes should not be enough to melt water under the Mars' surface. b) This would be exciting and surprising. Heat from Martian volcanoes should not be enough to melt water anywhere on the Mars. c) This would be exciting, but not surprising. Heat from Martian volcanoes may well be enough to melt water under the Mars' surface. d) This would be exciting, but not surprising. Heat from Martian volcanoes may well be enough to melt water anywhere on the Mars

c) This would be exciting, but not surprising. Heat from Martian volcanoes may well be enough to melt water under the Mars' surface.

All the following statements about Venus are true. Which one offers evidence of a global repaving about a billion years ago? a) Venus appears to lack any water that could lubricate the flow of rock in its crust and mantle. b) Venus has many circular features, called coronae, which appear to be tectonic in origin. c) Venus has relatively few impact craters and these craters are distributed fairly evenly over the entire planet. d) Venus's largest features are three elevated regions that look somewhat like continents.

c) Venus has relatively few impact craters and these craters are distributed fairly evenly over the entire planet.

Do you think seismology would work on the Moon? a) No, because there is no water or air. b) No, because the Moon is geologically dead. c) Yes.

c) Yes.

How fast do plates move on Earth? a) a few millimeters per century b) about 1 mile per hour c) a few centimeters per year d) quite fast, but only during earthquakes e) a few kilometers per century

c) a few centimeters per year

What is the lithosphere? a) another name for a planet's crust b) the crust plus the mantle c) a relatively rigid outer layer of rock that floats on molten rock below d) the boundary between the core and mantle

c) a relatively rigid outer layer of rock that floats on molten rock below

The lunar crater Tycho is about 80 km (50 miles) across. It was probably made by a) the eruption of the large volcano in its center. b) an impactor about 80 km across. c) an impactor about 8 km across. d) plate tectonics.

c) an impactor about 8 km across.

What seems to have made the very long cliffs on Mercury? a) volcanoes b) earthquakes c) cooling and shrinking when the planet became geologically dead d) meteorite impacts

c) cooling and shrinking when the planet became geologically dead

Which of the following does not transport heat out of a planet's interior? a) conduction b) convection c) differentiation d) radiation e) none of the above (all are processes that transport heat out of the interior)

c) differentiation

Shallow-sloped shield volcanoes are made from lava that a) is as runny as liquid water. b) can have any viscosity. c) has a medium viscosity. d) has a high viscosity.

c) has a medium viscosity.

Where in Earth is conduction the most important heat transport process? a) in the core b) in the mantle c) in the lithosphere d) in the crust

c) in the lithosphere

Which of the following has virtually no effect on the structure of a planet? a) its size b) its composition c) its magnetic field d) its mass

c) its magnetic field

Which of the following layers of a planet is not characterized by its density? a) core b) mantle c) lithosphere d) crust e) none of the above

c) lithosphere

Which two factors are most important to the existence of plate tectonics on Earth? a) the existence of life and oxygen in the atmosphere b) Earth's liquid outer core and solid inner core c) mantle convection and a thin lithosphere d) oxygen in the atmosphere and mantle convection

c) mantle convection and a thin lithosphere

What are the two geological features that appear to set Earth apart from all the other terrestrial worlds? a) significant volcanism and tectonics b) shield volcanoes and plate tectonics c) plate tectonics and widespread erosion d) mantle convection and a thick atmosphere

c) plate tectonics and widespread erosion

What are the 4 basic processes that shape planetary surfaces? a) magnetic fields, impacts, volcanoes, erosion b) magnetic fields, earthquakes, volcanoes, erosion c) tectonics, impacts, volcanoes, erosion d) magnetic fields, impacts, volcanoes, erosion e) tectonics, impacts, erosion, magnetic fields

c) tectonics, impacts, volcanoes, erosion

The distribution of craters on the surface of Venus suggests that a) its surface is ancient and has not been altered by volcanism, erosion or tectonics since the time of the heavy bombardment. b) parts of the surface are ancient, while others have been resurfaced within the last 100 million years. c) the entire planet was resurfaced about 750 million years ago. d) there has been ongoing regional resurfacing leading to a distribution of surface ages between about 100 million years and 750 million years.

c) the entire planet was resurfaced about 750 million years ago.

What is true of convection that stresses a planet's crust? a) Mountains may form where the crust is pushed together. b) Cracks and valleys may form where the crust is pulled apart. c) Convection has no effect on a planet's crust. d) A and B

d) A and B

Which of the following is not evidence of plate tectonics on Earth? a) There are fossils of similar species on widely separated continents. b) Seafloor crust is much younger than continental crust. c) Mid-ocean ridges are sites of mantle material eruption and seafloor spreading. d) Tidal forces from the Moon and Sun are strong enough to cause continental drift. e) none of the above (all are evidence of plate tectonics)

d) Tidal forces from the Moon and Sun are strong enough to cause continental drift.

Why is continental crust lower in density than seafloor crust? a) Continental crust is actually denser than seafloor crust. b) Seafloor crust is more compact due to the weight of the oceans, but it is made of the same material as the continental crust. c) Continental crust is made of rock, while seafloor crust has more metals. d) Continental crust is made from remelted seafloor crust and therefore only the lower-density material rises to form it. e) Continental crust is made from volcanic rock called basalt, which is lower in density than what the seafloor crust is made from.

d) Continental crust is made from remelted seafloor crust and therefore only the lower-density material rises to form it.

Which two bodies show evidence of a substantial atmosphere? a) Mercury and Venus b) Mercury and Earth c) Mercury and Earth's Moon d) Earth and Venus e) Earth and Mars

d) Earth and Venus

How does it explain the differences between seafloor and continental crust? a) Every time a bit of rock is subducted and expelled, its chemistry changes, making it heavier. The heavier rock becomes the seafloor plates, while the relatively unprocessed rocks are the continental plates. b) Every time a bit of rock is subducted and expelled, its chemistry changes, making it heavier. The heavier rock becomes the continental plates, while the relatively unprocessed rocks are the seafloor plates. c) Every time a bit of rock is subducted and expelled, its chemistry changes, making it lighter. The lighter rock becomes the seafloor plates, while the relatively unprocessed rocks are the continental plates. d) Every time a bit of rock is subducted and expelled, its chemistry changes, making it lighter. The lighter rock becomes the continental plates, while the relatively unprocessed rocks are the seafloor plates.

d) Every time a bit of rock is subducted and expelled, its chemistry changes, making it lighter. The lighter rock becomes the continental plates, while the relatively unprocessed rocks are the seafloor plates.

Suppose Venus rotated as fast as Earth. How would this change its relative levels of volcanism, tectonics, and erosion? a) All would remain the same - they are independent of rotation. b) All three would be higher. c) All three would be lower. d) Levels of volcanism and tectonics would stay the same, but erosion levels would be higher. e) Levels of volcanism and tectonics would be higher, and erosion levels would stay the same.

d) Levels of volcanism and tectonics would stay the same, but erosion levels would be higher.

Which of the following show evidence of ancient river beds? a) Mercury b) Venus c) the Moon d) Mars e) all of the above

d) Mars

Why are there fewer large impact craters on the Earth's seafloor than on the continents? a) Most impacts occur on the land. b) The oceans slow large impactors and prevent them from making craters. c) Erosion erases impact craters must faster on the ocean bottom than on land. d) Seafloor crust is younger than continental crust, so it has had less time in which to suffer impacts.

d) Seafloor crust is younger than continental crust, so it has had less time in which to suffer impacts.

The choices describe four hypothetical planets. Which one would you expect to have the most features of erosion? (Assume the planets orbit a star just like the Sun and that they are all the same age as the planets in our solar system.) a) Size: twice as big as Earth. Distance from Sun: same as Mercury. Rotation rate: once every 6 months. b) Size: same as the Moon. Distance from Sun: same as Mars. Rotation rate: once every 10 days. c) Size: same as Mars. Distance from Sun: same as Earth. Rotation rate: once every 18 hours. d) Size: same as Venus. Distance from Sun: same as Mars. Rotation rate: once every 25 hours.

d) Size: same as Venus. Distance from Sun: same as Mars. Rotation rate: once every 25 hours.

The choices describe four hypothetical planets. Which one's surface would you expect to be most crowded with impact craters? (Assume the planets orbit a star just like the Sun and that they are all the same age as the planets in our solar system.) a) Size: twice as big as Earth. Distance from Sun: same as Mercury. Rotation rate: once every 6 months. b) Size: same as Venus. Distance from Sun: same as Mars. Rotation rate: once every 25 hours. c) Size: same as Mars. Distance from Sun: same as Earth. Rotation rate: once every 18 hours. d) Size: same as the Moon. Distance from Sun: same as Mars. Rotation rate: once every 10 days.

d) Size: same as the Moon. Distance from Sun: same as Mars. Rotation rate: once every 10 days.

Many scientists suspect that Venus has a stronger and thicker lithosphere than Earth. If this is true, which of the following could explain it? a) The apparent lack of plate tectonics on Venus. b) The smaller size of Venus, which has allowed it to lose much more internal heat than Earth. c) The slow rotation of Venus. d) The high surface temperature that has "baked out" all the liquid water from Venus's crust and mantle.

d) The high surface temperature that has "baked out" all the liquid water from Venus's crust and mantle.

Which of the following is not generally true of all the terrestrial world lithospheres? a) Rock in the lithosphere is stronger than rock beneath it. b) The lithosphere extends from somewhere in the mantle all the way to the surface. c) The thickness of the lithosphere depends on interior temperature, with cooler interiors leading to thicker lithospheres. d) The lithosphere is broken into a set of large plates that float on the softer rock below.

d) The lithosphere is broken into a set of large plates that float on the softer rock below.

Under what circumstances can differentiation occur in a planet? a) The planet must be made of both metal and rock. b) The planet must have a rocky surface. c) The planet must be geologically active, that is, have volcanoes, planetquakes, and erosion from weather. d) The planet must have a molten interior. e) The planet must have an atmosphere.

d) The planet must have a molten interior.

Why do we think Mercury has so many tremendous cliffs? a) They are almost certainly volcanic in origin, carved by flowing lava. b) They were probably carved in Mercury's early history by running water. c) They probably formed when a series of large impacts hit Mercury one after the other. d) They were probably formed by tectonic stresses when the entire planet shrank as its core cooled. e) They represent one of the greatest mysteries in the solar system, as no one has suggested a reasonable hypothesis for their formation.

d) They were probably formed by tectonic stresses when the entire planet shrank as its core cooled.

Why are the lunar maria smooth? a) They formed after the heavy bombardment and therefore have fewer craters. b) The lava that formed the maria lacked gases and was therefore thin and runny. c) Bombardment of the Moon by meteoroids smoothed over any original rough features in the maria. d) The maria are liquid. e) A and B

e) A and B

A terrestrial world's lithosphere is ________. a) the interior region in which the planet's magnetic field is generated b) a layer of hot, molten rock encompassing the core and part of the mantle c) a thin layer of rock that lies between the mantle and crust d) a layer of relatively strong, rigid rock, encompassing the crust and part of the mantle

d) a layer of relatively strong, rigid rock, encompassing the crust and part of the mantle

Which of the following is not needed for a planet to have a global magnetic field? a) an electrically conducting fluid in the interior b) convection in the conducting fluid c) moderately rapid rotation d) a thick electrically conducting lithosphere

d) a thick electrically conducting lithosphere

What is basalt? a) any substance that evaporates easily and is a gas, liquid, or ice on Earth b) a type of metal that tends to create stratovolcanoes when eruptions occur c) a type of mineral that is the main ingredient of sea salt d) a type of rock that makes relatively low-viscosity lava e) another name for lava

d) a type of rock that makes relatively low-viscosity lava

Why does Earth have the youngest surface of all the terrestrial planets today? a) It is the largest terrestrial planet so its interior has not cooled too much. b) It is not so close to the Sun that it has lost its water and developed a thick lithosphere. c) It rotates rapidly. d) all of the above e) B and C

d) all of the above

Which internal energy source produces heat by converting gravitational potential energy into thermal energy? a) accretion b) differentiation c) radioactivity d) both A and B e) all of the above

d) both A and B

How have we been able to construct detailed maps of surface features on Venus? a) by making computer models of geological processes on Venus b) by landing spacecraft on the surface for close-up study c) by studying Venus with powerful optical telescopes on spacecraft that were sent to orbit Venus d) by using radar from spacecraft that were sent to orbit Venus e) by studying Venus from Earth with powerful telescopes

d) by using radar from spacecraft that were sent to orbit Venus

The core, mantle, and crust of a planet are defined by differences in their a) temperature. b) color. c) geological activity. d) composition. e) strength.

d) composition.

When we say that a liquid has a high viscosity, we mean that it a) is very dark in color. b) is runny like water. c) conducts electricity. d) flows slowly like honey. e) is very light in color.

d) flows slowly like honey.

Based on all we know about the terrestrial worlds, what single factor appears to play the most important role in a terrestrial planet's geological destiny? a) its distance from the Sun b) whether or not it has liquid water c) its composition d) its size

d) its size

Which of the following is the underlying reason why Venus has so little wind erosion? a) its thick atmosphere b) its small size c) its relatively close distance to the Sun d) its slow rotation

d) its slow rotation

The terrestrial planet cores contain mostly metal because a) radioactivity created metals in the core from the decay of uranium. b) convection carried the metals to the core. c) the entire planets are made mostly of metal. d) metals sank to the center during a time when the interiors were molten throughout. e) metals condensed first in the solar nebula and the rocks then accreted around them

d) metals sank to the center during a time when the interiors were molten throughout.

What is the source of Earth's magnetic field? a) magnetic rocks b) magnetized iron in Earth's crust c) magnetized iron in Earth's core d) molten metal circulating inside Earth

d) molten metal circulating inside Earth

The polar caps on Mars are composed of a) There are no polar caps on Mars. b) mostly water ice and some c) solid carbon dioxide. pure water ice. d) mostly solid carbon dioxide and some water ice. e) pure solid carbon dioxide.

d) mostly solid carbon dioxide and some water ice.

Which of the following is not evidence that has been found for liquid water on Mars's surface in the past? a) the presence of iron-bearing spheres called "blueberries" that form in water b) layered deposits similar to sedimentary rocks c) ancient riverbeds d) none of the above (all are evidence of past water) e) all of the above (none are evidence of past water)

d) none of the above (all are evidence of past water)

What process has shaped Earth's surface more than any other? a) impact cratering b) acid rain c) volcanism d) plate tectonics e) erosion

d) plate tectonics

Which of the following describes tectonics? a) the eruption of molten rock from a planet's interior to its surface b) the wearing down or building up of geological features by wind, water, ice, and other phenomena of planetary weather c) the excavation of bowl-shaped depressions by asteroids or comets striking a planet's surface d) the disruption of a planet's surface by internal stresses

d) the disruption of a planet's surface by internal stresses

Which of the following describes volcanism? a) the disruption of a planet's surface by internal stresses b) the eruption of molten rock from a planet's interior to its surface c) the excavation of bowl-shaped depressions by asteroids or comets striking a planet's surface d) the wearing down or building up of geological features by wind, water, ice, and other phenomena of planetary weather

d) the wearing down or building up of geological features by wind, water, ice, and other phenomena of planetary weather

How do we know that Earth is geologically active? a) volcanoes b) seismology c) measurements of internal temperature d) all of the above e) A and B

e) A and B

How do we learn about Earth's core, mantle, and crust? a) deep drilling b) seismic waves c) X-ray imaging d) all of the above e) A and B

e) A and B

Plumes of hot mantle material are responsible for a) the formation of the Hawaiian Islands. b) the geysers of Yellowstone National Park. c) the Appalachian mountains. d) all of the above. e) A and B

e) A and B

What's the fundamental reason that Mars has so little geological activity compared to Earth? a) its farther distance than Earth to the Sun b) its rapid rotation compared to the Earth c) its closer distance than Earth to the Sun d) its slow rotation compared to the Earth e) its small size compared to Earth f) its large size compared to the Earth

e) its small size compared to Earth

Which of the following does not have a major effect in shaping planetary surfaces? a) volcanism b) tectonics c) erosion d) impact cratering e) magnetism

e) magnetism

Olympus Mons is a a) shield volcano on Venus. b) large lava plain on the Moon. c) stratovolcano on Mercury. d) stratovolcano on the Moon. e) shield volcano on Mars

e) shield volcano on Mars

What is differentiation in planetary geology? a) any process by which one part of a planet's surface evolves differently from another part of the same planet's surface b) the process by which different types of minerals form a conglomerate rock c) any process by which a planet evolves differently from its moons d) any process by which a planet's surface evolves differently from another planet's surface e) the process by which gravity separates materials according to density

e) the process by which gravity separates materials according to density

When we see a region of a planet that is not as heavily cratered as other regions, we conclude that a) the planet formed after the age of bombardment and missed out on getting hit by leftover planetesimals. b) there is little volcanic activity to create craters. c) the surface in the region is older than the surface in more heavily cratered regions. d) the planet is rotating very slowly and only one side was hit by impactors. e) the surface in the region is younger than the surface in more heavily cratered regions

e) the surface in the region is younger than the surface in more heavily cratered regions