ASTR Chapter 9
22) Which of the following has virtually no effect on the structure of a planet? A) its composition B) its size C) its magnetic field D) its mass
Answer: C
13) The three principal sources of internal heat of terrestrial planets are A) conduction, differentiation, and accretion. B) accretion, differentiation, and radioactivity. C) accretion, differentiation, and eruption. D) convection, differentiation, and eruption. E) conduction, convection, and eruption.
Answer: B
20) Which of the following most likely explains why Venus does not have a strong magnetic field? A) It does not have a metallic core. B) Its rotation is too slow. C) It is too close to the Sun. D) It is too large. E) It has too thick an atmosphere.
Answer: B
23) Which two properties are most important in determining the surface temperature of a planet? A) composition and distance from the Sun B) size and chemical composition C) size and atmosphere D) internal temperature and atmosphere E) distance from the Sun and atmosphere
Answer: E
24) Which of the following does not have a major effect in shaping planetary surfaces? A) impact cratering B) volcanism C) tectonics D) erosion E) magnetism
Answer: E
27) When we see a region of a planet that is not as heavily cratered as other regions, we conclude that A) there is little volcanic activity to create craters. B) the planet is rotating very slowly and only one side was hit by impactors. C) the planet formed after the age of bombardment and missed out on getting hit by leftover planetesimals. D) the surface in the region is older than the surface in more heavily cratered regions. E) the surface in the region is younger than the surface in more heavily cratered regions.
Answer: E
3) Under what circumstances can differentiation occur in a planet? A) The planet must have a rocky surface. B) The planet must be made of both metal and rock. C) The planet must have an atmosphere. D) The planet must be geologically active, that is, have volcanoes, planetquakes, and erosion from weather. E) The planet must have a molten interior.
Answer: E
57) How long, approximately, do geologists estimate it takes for the entire seafloor to be replaced due to plate tectonics? A) 2 million years B) 20 million years C) 200 million years D) 2 billion years E) longer than the age of the solar system
Answer: C
43) Olympus Mons is a A) shield volcano on Mars. B) stratovolcano on Mercury. C) large lava plain on the Moon. D) shield volcano on Venus. E) stratovolcano on the Moon.
Answer: A
14) The main process by which heat flows upward through the lithosphere is A) conduction. B) convection. C) radiation. D) accretion. E) differentiation.
Answer: A
15) Heat escapes from a planet's surface into space by thermal radiation. Planets radiate almost entirely in the wavelength range of the A) infrared. B) radio. C) visible. D) ultraviolet. E) none of the above
Answer: A
2) What is differentiation in planetary geology? A) the process by which gravity separates materials according to density B) the process by which different types of minerals form a conglomerate rock C) any process by which a planet's surface evolves differently from another planet's surface D) any process by which one part of a planet's surface evolves differently from another part of the same planet's surface E) any process by which a planet evolves differently from its moons
Answer: A
35) Which of the following describes impact cratering? A) the excavation of bowl-shaped depressions by asteroids or comets striking a planet's surface B) the eruption of molten rock from a planet's interior to its surface C) the disruption of a planet's surface by internal stresses D) the wearing down or building up of geological features by wind, water, ice, and other phenomena of planetary weather
Answer: A
39) How did the lunar maria form? A) Large impacts fractured the Moon's lithosphere, allowing lava to fill the impact basins. B) The early bombardment created heat that melted the lunar surface in the regions of the maria. C) Volatiles escaping from the Moon's interior heated and eroded the surface in the regions of the maria. D) The giant impact that created the Moon left smooth areas that we call the maria. E) The maria are the result of gradual erosion by micrometeorites striking the Moon.
Answer: A
50) Spacecraft have landed on all the terrestrial worlds except A) Mercury. B) Venus. C) Moon. D) Mars.
Answer: A
52) Why are there fewer large craters on the seafloor than on the continents? A) The seafloor crust is younger than the continental crust. B) The oceans slow large impactors and prevent them from making craters. C) The oceans erode away craters faster than erosion processes on land. D) Large impactors primarily strike land masses. E) Large impactors aim for life-forms such as dinosaurs.
Answer: A
54) Why is continental crust lower in density than seafloor crust? A) Continental crust is made from remelted seafloor crust and therefore only the lower-density material rises to form it. B) Continental crust is made from volcanic rock called basalt, which is lower in density than what the seafloor crust is made from. C) Continental crust is made of rock, while seafloor crust has more metals. D) Seafloor crust is more compact due to the weight of the oceans, but it is made of the same material as the continental crust. E) Continental crust is actually denser than seafloor crust.
Answer: A
56) How fast do plates move on Earth? A) a few centimeters per year B) a few millimeters per century C) a few kilometers per century D) quite fast, but only during earthquakes E) about 1 mile per hour
Answer: A
58) What drives the motion of the tectonic plates on Earth? A) convection cells in the mantle B) lava flows in trenches along the sea floor C) the Coriolis force D) Earth's magnetic field E) tidal forces
Answer: A
60) Deep trenches in the ocean mark places where A) one plate slides under another, returning older crust to the mantle. B) plates pull apart, leaving great rifts in the crust. C) hot mantle material rises upward and spreads sideways, pushing the plates apart. D) plates push together, creating ocean mountain chains. E) plates slip sideways relative to one another.
Answer: A
18) Which of the terrestrial worlds has the strongest magnetic field? A) Mars B) Earth C) the Moon D) Venus E) Mercury
Answer: B
11) 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 warm material expands and rises while cool material contracts and falls. C) It is the process in which warm material gets even warmer and cool material gets even cooler. D) It is the process in which a liquid separates according to density, such as oil and water separating in a jar. E) It is the process in which bubbles of gas move upward through a liquid of the same temperature.
Answer: B
26) The relatively few craters that we see within the lunar maria A) were formed by impacts that occurred before those that formed most of the craters in the lunar highlands. B) were formed by impacts that occurred after those that formed most of the craters in the lunar highlands. C) were created by the same large impactor that led to the formation of the maria. D) are volcanic in origin, rather than from impacts. E) are sinkholes that formed when sections of the maria collapsed.
Answer: B
29) Shallow-sloped shield volcanoes are made from lava that A) is as runny as liquid water. B) has a medium viscosity. C) has a high viscosity. D) can have any viscosity.
Answer: B
34) Which of the following describes volcanism? A) the excavation of bowl-shaped depressions by asteroids or comets striking a planet's surface B) the eruption of molten rock from a planet's interior to its surface C) the disruption of a planet's surface by internal stresses D) the wearing down or building up of geological features by wind, water, ice, and other phenomena of planetary weather
Answer: B
38) What is basalt? A) any substance that evaporates easily and is a gas, liquid, or ice on Earth B) a type of rock that makes relatively low-viscosity lava C) a type of metal that tends to create stratovolcanoes when eruptions occur D) a type of mineral that is the main ingredient of sea salt E) another name for lava
Answer: B
4) When we say that a liquid has a high viscosity, we mean that it A) is runny like water. B) flows slowly like honey. C) is very dark in color. D) is very light in color. E) conducts electricity.
Answer: B
42) Why do we think Mercury has so many tremendous cliffs? A) They were probably carved in Mercury's early history by running water. B) They were probably formed by tectonic stresses when the entire planet shrank as its core cooled. C) They probably formed when a series of large impacts hit Mercury one after the other. D) They are almost certainly volcanic in origin, carved by flowing lava. E) They represent one of the greatest mysteries in the solar system, as no one has suggested a reasonable hypothesis for their formation.
Answer: B
53) How does seafloor crust differ from continental crust? A) Seafloor crust is thicker, older, and higher in density. B) Seafloor crust is thinner, younger, and higher in density. C) Seafloor crust is thinner, older, and lower in density. D) Seafloor crust is thicker, older, and lower in density. E) Seafloor crust is thicker, younger, and lower in density.
Answer: B
63) The geysers and hot springs of Yellowstone National Park result from A) thin continental crust separating and creating a rift valley. B) plumes of hot mantle rising in a hot spot within a plate. C) plates that have slipped sideways relative to each other, creating a fault. D) a plate that has run up against an existing continental plate. E) a fault.
Answer: B
31) What type of stresses broke Earth's lithosphere into plates? A) impacts of asteroids and planetesimals B) internal temperature changes that caused the crust to expand and stretch C) the circulation of convection cells in the mantle, which dragged against the lithosphere D) cooling and contracting of the planet's interior, which caused the mantle and lithosphere to be compressed E) volcanism, which produced heavy volcanoes that bent and cracked the lithosphere
Answer: C
6) The lithosphere of a planet is the layer that consists of A) material above the crust. B) material between the crust and the mantle. C) the rigid rocky material of the crust and uppermost portion of the mantle. D) the softer rocky material of the mantle. E) the lava that comes out of volcanoes.
Answer: C
10) Which internal energy source is the most important in continuing to heat the terrestrial planets today? A) accretion B) differentiation C) radioactivity D) tidal heating E) all of the above
Answer: C
19) Why does Earth have the strongest magnetic field among the terrestrial worlds? A) It is the only one that has a metallic core. B) It rotates much faster than any other terrestrial world. C) It is the only one that has both a partially molten metallic core and reasonably rapid rotation. D) It is by far the largest terrestrial world. E) It is the most volcanically active world.
Answer: C
25) How large is an impact crater compared to the size of the impactor? A) the same size B) 10-20 percent larger C) 10 times larger D) 100 times larger E) 1,000 times larger
Answer: C
28) Volcanism is more likely on a planet that A) is closer to the Sun. B) is struck often by meteors and solar system debris. C) has high internal temperatures. D) doesn't have an atmosphere or oceans.
Answer: C
30) Steep-sided stratovolcanoes are made from lava that A) is as runny as liquid water. B) has a medium viscosity. C) has a high viscosity. D) can have any viscosity.
Answer: C
32) Which of the following describes tectonics? A) the excavation of bowl-shaped depressions by asteroids or comets striking a planet's surface B) the eruption of molten rock from a planet's interior to its surface C) the disruption of a planet's surface by internal stresses D) the wearing down or building up of geological features by wind, water, ice, and other phenomena of planetary weather
Answer: C
45) Which of the following does not provide evidence that Mars once had flowing water? A) the presence of what looks like dried-up riverbeds B) the presence of impact craters that appear to have formed in mud C) the presence of vast canals discovered in the late 1800s by Giovanni Schiaparelli and mapped by Percival Lowell D) rocks of many different types jumbled together, as would occur if there had once been a great flood in the region, found by the Mars Pathfinder E) some very old craters that appear to have been eroded by rain
Answer: C
46) The polar caps on Mars are composed of A) pure solid carbon dioxide. B) pure water ice. C) mostly solid carbon dioxide and some water ice. D) mostly water ice and some solid carbon dioxide. E) There are no polar caps on Mars.
Answer: C
51) What process has shaped Earth's surface more than any other? A) impact cratering B) volcanism C) plate tectonics D) erosion E) acid rain
Answer: C
59) Ridges in the middle of the ocean are places where A) one plate slides under another, returning older crust to the mantle. B) hot mantle material rises upward, creating volcanic islands. C) hot mantle material rises upward and spreads sideways, pushing the plates apart. D) plates push together, creating ocean mountain chains. E) plates slip sideways relative to one another.
Answer: C
62) Which of the following regions was the result of plumes of hot mantle rising in a hot spot within a plate? A) Alaska's Aleutian Islands B) Japan and the Philippines C) the islands of Hawaii D) the volcano Mount St. Helens E) all of the above
Answer: C
65) Which of the following does not provide evidence for water on Mars? A) dry riverbeds B) eroded craters C) canal structures observed by Percival Lowell D) groupings of rocks that appear to have been deposited as in a flood
Answer: C
8) The terrestrial planet cores contain mostly metal because A) the entire planets are made mostly of metal. B) metals condensed first in the solar nebula and the rocks then accreted around them. C) metals sank to the center during a time when the interiors were molten throughout. D) radioactivity created metals in the core from the decay of uranium. E) convection carried the metals to the core.
Answer: C
49) Which of the following show evidence of ancient river beds? A) the Moon B) Mercury C) Venus D) Mars E) all of the above
Answer: D
55) Which of the following is not evidence for plate tectonics on Earth? A) some continental boundaries fit together like pieces of a jigsaw puzzle B) similar rocks and fossils are found in different continents C) high ocean ridges between the continents D) existence of volcanoes E) earthquakes
Answer: D
1) Rank the five terrestrial worlds in order of size from smallest to largest: A) Mercury, Venus, Earth, Moon, Mars. B) Mercury, Moon, Venus, Earth, Mars. C) Moon, Mercury, Venus, Earth, Mars. D) Moon, Mercury, Mars, Venus, Earth. E) Mercury, Moon, Mars, Earth, Venus.
Answer: D
17) Which of the following best describes why the smaller terrestrial worlds have cooler interiors than the larger ones? A) They were cooler when they formed. B) The smaller ones are farther from the Sun. C) They have relatively fewer radioactive elements. D) They have relatively more surface area compared to their volumes. E) They had more volcanic eruptions in the past, which released their internal heat.
Answer: D
21) What are the conditions necessary for a terrestrial planet to have a strong magnetic field? A) a molten metallic core only B) fast rotation only C) a rocky mantle only D) both a molten metallic core and reasonably fast rotation E) both a metal core and a rocky mantle
Answer: D
33) Which of the following describes erosion? A) the excavation of bowl-shaped depressions by asteroids or comets striking a planet's surface B) the eruption of molten rock from a planet's interior to its surface C) the disruption of a planet's surface by internal stresses D) the wearing down or building up of geological features by wind, water, ice, and other phenomena of planetary weather
Answer: D
36) A planet is most likely to have tectonic activity if it has A) low surface gravity. B) high surface gravity. C) low internal temperature. D) high internal temperature. E) a dense atmosphere.
Answer: D
41) The Caloris Basin on Mercury covers a large region of the planet, but few smaller craters have formed on top of it. From this we conclude that A) erosion destroyed the smaller craters that formed on the basin. B) Mercury's atmosphere prevented smaller objects from hitting the surface. C) only very large impactors hit Mercury's surface in the past. D) the Caloris Basin formed toward the end of the solar system's period of heavy bombardment. E) the Caloris Basin was formed by a volcano.
Answer: D
44) Valles Marineris is a A) large valley on the Moon. B) vast plain on Mars. C) huge series of cliffs on Mercury. D) large canyon on Mars. E) large canyon on Venus.
Answer: D
47) How have we been able to construct detailed maps of surface features on Venus? A) by studying Venus from Earth with powerful telescopes B) by studying Venus with powerful optical telescopes on spacecraft that were sent to orbit Venus C) by making computer models of geological processes on Venus D) by using radar from spacecraft that were sent to orbit Venus E) by landing spacecraft on the surface for close-up study
Answer: D
48) Which two geological processes appear to have been most important in shaping the present surface of Venus? A) impacts and volcanoes B) impacts and tectonics C) tectonics and erosion D) volcanoes and tectonics E) volcanoes and erosion
Answer: D
5) The core, mantle, and crust of a planet are defined by differences in their A) geological activity. B) temperature. C) strength. D) composition.
Answer: D
7) What is the most important factor that determines the thickness, and therefore strength, of the lithosphere? A) pressure B) viscosity C) composition D) internal temperature E) distance of planet from Sun
Answer: D
9) 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
Answer: D
12) What are the circumstances under which convection can occur in a substance? A) when the substance is subjected to a strong magnetic field B) when dense material is being added to the substance C) when the substance is strongly shaken or disturbed by a strong wind D) when the substance is strongly cooled from underneath E) when the substance is strongly heated from underneath
Answer: E
37) What kind of surface features may result from tectonics? A) mountains B) valleys C) volcanos D) cliffs E) all of the above
Answer: E
61) Some of the oldest continental crust on Earth lies in A) Hawaii. B) California. C) the Great Plains. D) the deep South. E) Northeastern Canada.
Answer: E
16) Which of the following worlds have the thinnest lithospheres? A) Earth and the Moon B) Venus and the Moon C) Mercury and Venus D) Earth and Mars E) Earth and Venus
Answer: E
40) Why does the Moon have a layer of powdery "soil" on its surface? A) Large impacts shattered lunar rock to make this soil. B) The soil exists because the Moon accreted from powdery material after a giant impact blasted Earth. C) Volatiles escaping from the Moon's interior bubble upward and make the soil. D) The soil is the result of the same processes that make powdery sand on Earth. E) It's the result of gradual erosion by micrometeorites striking the Moon.
Answer: E
64) Mineral evidence shows that Earth's oceans have existed for A) millions of years. B) several ten million years. C) several hundred million years. D) several billion years. E) over four billion years.
Answer: E
10) In the inner solar system, the largest surface features are found on the largest planets.
Answer: FALSE
11) Earth is the only terrestrial planet to have experienced tectonic stresses and volcanic activity.
Answer: FALSE
4) Smaller worlds generally have thinner lithospheres.
Answer: FALSE
6) The magnetic and rotational north poles on Earth are the same.
Answer: FALSE
8) Erosion is the most important geological process on Venus.
Answer: FALSE
9) There is no erosion of surface features on the Moon.
Answer: FALSE
5) Earth is the only planet in the solar system known to have plate tectonics.
Answer: TRUE
1) The strength of a rock depends on its composition, its temperature, and the surrounding pressure.
Answer: TRUE
12) Much of the land on the west coast of North America began as volcanic islands in the Pacific.
Answer: TRUE
13) Spreading centers are marked by mid-ocean ridges where hot mantle material rises upward and then spreads sideways.
Answer: TRUE
14) The process in which one plate slides under another is called subduction and is marked by deep ocean trenches.
Answer: TRUE
2) Higher temperatures make rocks weaker.
Answer: TRUE
3) 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.
Answer: TRUE
7) Mars has virtually no magnetic field.
Answer: TRUE
