AST 1002 Exam 2

Why does the burning of fossil fuels increase the greenhouse effect on Earth? A) Burning releases carbon dioxide into the atmosphere. B) Burning depletes the amount of ozone, thereby warming the planet. C) Burning fuel warms the planet. D) Burning produces infrared light, which is then trapped by existing greenhouse gases.

A) Burning releases carbon dioxide into the atmosphere.

Why is Mars red? A) Chemical reactions between surface rock and atmospheric oxygen literally rusted the surface. B) Martian volcanoes released a much redder lava than volcanoes on Earth. C) The red color is caused by water ice chemically bound in surface rock. D) The red color of Mars is a result of the scattering of light in the Martian sky.

A) Chemical reactions between surface rock and atmospheric oxygen literally rusted the surface.

How does Earth's magnetosphere affect our atmosphere? A) It deflects solar wind particles that would otherwise strip away the atmosphere. B) It scatters the shorter wavelengths of light from the sun and causes the sky to be blue. C) It produces chemical reactions that cause ozone to form in the upper atmosphere. D) all of the above

A) It deflects solar wind particles that would otherwise strip away the atmosphere.

Why did the solar nebula flatten into a disk? A) It flattened as a natural consequence of collisions between particles in the nebula, changing random motions into more orderly ones. B) The force of gravity pulled the material downward into a flat disk. C) As the nebula cooled, the gas and dust settled onto a disk. D) The interstellar cloud from which the solar nebula formed was originally somewhat flat.

A) It flattened as a natural consequence of collisions between particles in the nebula, changing random motions into more orderly ones.

According to our theory of solar system formation, what three major changes occurred in the solar nebula as it shrank in size? A) It got hotter, its rate of rotation increased, and it flattened into a disk. B) Its gas clumped up to form the terrestrial planets, nuclear fusion produced heavy elements to make the jovian planets, and central temperatures rose to more than a trillion Kelvin. C) It gained energy, it gained angular momentum, and it flattened into a disk. D) Its mass, temperature, and density all increased.

A) It got hotter, its rate of rotation increased, and it flattened into a disk.

Why does Earth have the strongest magnetic field among the terrestrial worlds? A) It is the only one that has both a molten metallic outer core and reasonably rapid rotation. B) It is the only one that has a molten metallic outer core. C) It is by far the largest terrestrial world. D) It rotates much faster than any other terrestrial world. E) It is the most volcanically active world.

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

All of the following statements about Mars are true. Which one might have led to a significant loss of atmospheric gas to space? A) Mars lost any global magnetic field that it may once have had. B) Mars probably once had a much higher density of greenhouse gases in its atmosphere than it does today. C) The axis tilt of Mars is thought to change significantly over time. D) Oxygen reacts chemically with surface rock on Mars.

A) Mars lost any global magnetic field that it may once have had.

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's interior has cooled so much its molten core layer no longer undergoes convection. B) Mars is too far from the Sun to have a global magnetic field. C) The Martian core is made of rock, while Earth's core is made of metal. D) Mars rotates much slower than the Earth.

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

Which of the following lists the planets of our solar system in the correct order from closest to farthest from the Sun? A) Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune B) Mercury, Venus, Mars, Earth, Saturn, Jupiter, Neptune, Uranus C) Mercury, Earth, Venus, Mars, Jupiter, Saturn, Neptune, Uranus D) Earth, Mars, Mercury, Venus, Jupiter, Saturn, Uranus, Neptune

A) Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune

Overall, what do current data suggest about planetary types in other planetary systems? A) Planets come in a wider range of types than the planets in our solar system. B) Jovian planets are very common while terrestrial planets are very rare. C) All planets fall into the same terrestrial and jovian categories as the planets in our solar system. D) Planets that fall into either the terrestrial or jovian categories are extremely rare outside of our own solar system.

A) Planets come in a wider range of types than the planets in our solar system.

In light of what you've learned about the formation of our own solar system, decide whether the discovery should be considered reasonable or surprising. A) Reasonable. This is very close to the layout of our solar system B) Surprising. According to our current theories, the moons cannot have highly inclined orbits relative to the ecliptic plane.

A) Reasonable. This is very close to the layout of our solar system.

The choices below 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: same as the Moon. Distance from Sun: same as Mars. Rotation rate: once every 10 days. B) Size: same as Mars. Distance from Sun: same as Earth. Rotation rate: once every 18 hours. C) Size: twice as big as Earth. Distance from Sun: same as Mercury. Rotation rate: once every 6 months. E) Size: same as Venus. Distance from Sun: same as Mars. Rotation rate: once every 25 hours.

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

In light of what you've learned about the formation of our own solar system, decide whether the discovery should be considered reasonable or surprising. A) Surprising. According to our current theories, objects that form beyond the jovian planets should include a great deal of ice. B) Reasonable. This is very close to the layout of our solar system.

A) Surprising. According to our current theories, objects that form beyond the jovian planets should include a great deal of ice.

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 maria formed after the heavy bombardment ended. B) The regions of the maria were hit by fewer impacts than the densely cratered regions. C) Erosion affects the maria more than it affects other regions of the Moon. D) The maria formed within the past 1 billion years.

A) The maria formed after the heavy bombardment ended.

Which of the following general statements about Earth's atmosphere is not true? A) The nitrogen and oxygen in Earth's atmosphere keep the surface pleasantly warm. B) Gas high in the atmosphere absorbs dangerous X-rays from the Sun. C) Without the relatively rare gas called ozone, Earth's surface would be bathed in dangerous ultraviolet light from the Sun. D) The oxygen in our atmosphere was released by living organisms.

A) The nitrogen and oxygen in Earth's atmosphere keep the surface pleasantly warm.

Which of the following is not a characteristic of the inner planets? A) They have substantial atmospheres. B) They have solid, rocky surfaces. C) Their orbits are relatively closely spaced. D) They have relatively high densities. E) They are smaller than the outer planets.

A) They have substantial atmospheres.

What is the origin of the large moons orbiting in the equatorial planes of the jovian planets? A) They were formed by condensation and accretion in a disk of gas around the planet. B) They are captured planets. C) They are captured comets. D) They were formed by giant impacts. E) They are captured asteroids.

A) They were formed by condensation and accretion in a disk of gas around the planet.

The terrestrial planets are made almost entirely of elements heavier than hydrogen and helium. According to modern science, where did these elements come from? A) They were produced by stars that lived and died before our solar system was born. B) They were made by chemical reactions in interstellar gas. C) They have been present in the universe since its birth. D) They were produced in the core of the Sun.

A) They were produced by stars that lived and died before our solar system was born.

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) lower density bubbles form and rise upward in boiling water C) thunderstorms tend to form on hot summer days D) Earth contains more metal than the Moon

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

Suppose we represent Earth with a basketball. On this scale, most of the air in Earth's atmosphere would fit in a layer that is ________. A) about the thickness of a sheet of paper B) about 6 inches thick C) about an inch thick D) about a half-inch thick

A) about the thickness of a sheet of paper

What process initially caused the terrestrial planets to be hot enough to be entirely molten? A) accretion B) differentiation C) radioactivity D) conduction E) convection

A) accretion

From center to surface, which of the following correctly lists the interior layers of a terrestrial world? A) core, mantle, lithosphere, crust B) core, mantle, crust, lithosphere C) mantle, core, crust, lithosphere D) mantle, core, lithosphere, crust

A) core, mantle, lithosphere, crust

Which internal heat source still actively generates heat within the terrestrial worlds today? A) heat from radioactive decay B) heat from convection C) heat of accretion D) heat from differentiation

A) heat from radioactive decay

What is Jupiter's main ingredient? A) hydrogen and helium B) hydrogen compounds C) rock and metal

A) hydrogen and helium

According to our present theory of solar system formation, which of the following lists the major ingredients of the solar nebula in order from the most abundant to the least abundant? A) hydrogen and helium gas; hydrogen compounds; rock; metal B) hydrogen, water, methane, helium C) hydrogen compounds; hydrogen and helium gas; metal; rock D) hydrogen and helium gas; rock; metal; hydrogen compounds

A) hydrogen and helium gas; hydrogen compounds; rock; metal

Which of the following is the main reason why Venus has so little wind erosion? A) its slow rotation B) its small size C) its relatively close distance from the Sun D) its thick atmosphere

A) its slow rotation

In essence, the nebular theory holds that _________. A) our solar system formed from the collapse of an interstellar cloud of gas and dust B) nebulae are clouds of gas and dust in space C) the nebular theory is a discarded idea that imagined planets forming as a result of a near-collision between our Sun and another star D) the planets each formed from the collapse of its own separate nebula

A) our solar system formed from the collapse of an interstellar cloud of gas and dust

Which of the following best describes the lunar maria? A) relatively smooth, flat plains on the Moon B) frozen oceans of liquid water on the Moon C) mountainous regions on the Moon D) densely cratered regions on the Moon

A) relatively smooth, flat plains on the Moon

Which of the following best 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 lithosphere by internal stresses D) the wearing down or building up of geological features by wind, water, ice, and other phenomena of planetary weather

A) the excavation of bowl-shaped depressions by asteroids or comets striking a planet's surface

About how old is the solar system? A) 4.5 million years B) 4.5 billion years C) 4.5 trillion years

B) 4.5 billion years

What observational evidence supports the idea that Mercury shrank after it formed? A) Mercury's unusually high density B) the presence of many long, tall cliffs C) the presence of many impact craters D) the characteristics of the Caloris Basin

B) the presence of many long, tall cliffs

In the context of planetary geology, what do we mean by outgassing? A) another name for a volcanic eruption B) the release by volcanism of gases that had been trapped in a planetary interior C) the loss of atmospheric gas to outer space D) the evaporation of water that adds water vapor (a gas) to an atmosphere

B) the release by volcanism of gases that had been trapped in a planetary interior

Which of the following best describes the geological histories of the Moon and Mercury? A) Impact cratering and erosion are the only major geological processes that has affected their surfaces. B) All four geological processes were important in their early histories, but only impact cratering still reshapes their surfaces today. C) Early in their histories, they suffered many impacts and experienced some volcanism and tectonics, but they now have little geological activity at all. 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.

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

What do we mean by the frost line when we discuss the formation of planets in the solar nebula? A) It is another way of stating the temperature at which water freezes into ice. B) It is the altitude in a planet's atmosphere at which snow can form. C) It is a circle at a particular distance from the Sun, beyond which the temperature was low enough for ices to condense. D) It marks the special distance from the Sun at which hydrogen compounds become abundant; closer to the Sun, there are no hydrogen compounds.

C) It is a circle at a particular distance from the Sun, beyond which the temperature was low enough for ices to condense.

What's unusual about our Moon? A) It's the only moon that orbits a terrestrial planet. B) It's by far the largest moon in the solar system. C) It's surprisingly large relative to the planet it orbits.

C) It's surprisingly large relative to the planet it orbits.

The jovian planets in our solar system are _________. A) Io, Europa, Ganymede, and Callisto B) Pluto and Eris C) Jupiter, Saturn, Uranus, and Neptune D) Mercury, Venus, Earth, and Mars

C) Jupiter, Saturn, Uranus, and Neptune

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, Mars, Venus, Earth D) Mercury, Moon, Mars, Earth, Venus E) Moon, Mercury, Venus, Earth, Mars

C) Moon, Mercury, Mars, Venus, Earth

According to our theory of solar system formation, what are asteroids and comets? A) the shattered remains of collisions between planets B) chunks of rock or ice that were expelled from planets by volcanoes C) leftover planetesimals that never accreted into planets D) chunks of rock or ice that condensed after the planets and moons finished forming

C) leftover planetesimals that never accreted into planets

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

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

Which of the following best 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 lithosphere by internal stresses D) the wearing down or building up of geological features by wind, water, ice, and other phenomena of planetary weather

C) the disruption of a planet's lithosphere by internal stresses

Which of the following does the solar nebular theory not predict? A) planets orbit the Sun in the same direction B) the presence of asteroids and comets C) the equal number of terrestrial and jovian planets D) planets orbit the Sun in nearly circular orbits in a flattened disk E) the compositional differences between the terrestrial and jovian planets

C) the equal number of terrestrial and jovian planets

According to our theory of solar system formation, which law best explains why the solar nebula spun faster as it shrank in size? A) the law of conservation of energy B) Einstein's law E = mc2 C) the law of conservation of angular momentum D) the law of universal gravitation

C) the law of conservation of angular momentum

The age of the solar system can be established by radiometric dating of A) the oldest rocks on the Moon. B) the atmosphere of Mars. C) the oldest meteorites. D) the oldest rocks on Earth. E) It hasn't been done yet, but the age of the solar system could be obtained from a sample of Io's surface.

C) the oldest meteorites.

Observations of young stars (as well as theory) tell us that when the Sun was young, the solar wind A) was weaker than it is today. B) had a different composition than it does today. C) was stronger than it is today. D) was about the same strength as it is today. E) was nonexistent.

C) was stronger than it is today.

What percentage of the mass of the solar nebula consisted of elements other than hydrogen and helium? A) 0.1 percent B) 20 percent C) 0 percent D) 2 percent E) 80 percent

D) 2 percent

Suppose you view the solar system from high above Earth's North Pole. Which of the following statements about planetary orbits will be true? A) The inner planets orbit the Sun clockwise while the outer planets orbit the Sun counterclockwise. B) All the planets except Uranus orbit the Sun counterclockwise; Uranus orbits in the opposite direction. C) The inner planets orbit the Sun counterclockwise while the outer planets orbit the Sun clockwise. D) All the planets orbit counterclockwise around the Sun.

D) All the planets orbit counterclockwise around the Sun.

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 bubbles of gas move upward through a liquid. C) It is the process in which a liquid separates according to density, such as oil and water separating in a jar. D) It is the process in which warm material expands and rises while cool material contracts and falls. E) It is the process in which warm material gets even warmer and cool material gets even cooler.

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

Why are terrestrial planets more dense than the jovian planets? A) Gravity compresses terrestrial planets to a higher degree, making them denser. B) Since the jovian planets are more massive than the terrestrials, the jovians must be more dense. C) The Sun's gravity pulled dense materials into the inner solar system. D) Only dense materials could condense in the inner solar nebula.

D) Only dense materials could condense in the inner solar nebula.

Which of the following is not a major difference between the terrestrial and jovian planets in our solar system? A) Jovian planets have rings, and terrestrial planets do not. B) Terrestrial planets are higher in average density than jovian planets. C) Terrestrial planets orbit much closer to the Sun than jovian planets. D) Terrestrial planets contain large quantities of ice, and jovian planets do not.

D) Terrestrial planets contain large quantities of ice, and jovian planets do not.

Which of the following best describes how the greenhouse effect works? A) Greenhouse gases absorb infrared light coming from the Sun, and this absorbed sunlight heats the lower atmosphere and the surface. B) A planet's surface absorbs visible sunlight and returns this absorbed energy to space as infrared light. Greenhouse gases slow the escape of this infrared radiation, which thereby heats the lower atmosphere. C) Greenhouse gases absorb X-rays and ultraviolet light from the Sun, and this absorbed radiation then heats the atmosphere and the surface. D) The greenhouse effect is caused primarily by ozone, which absorbs ultraviolet light and thereby makes the atmosphere much hotter than it would be otherwise.

B) A planet's surface absorbs visible sunlight and returns this absorbed energy to space as infrared light. Greenhouse gases slow the escape of this infrared radiation, which thereby heats the lower atmosphere.

Why did the solar nebula heat up as it collapsed? A) The shock wave from a nearby supernova heated the gas. B) As the cloud shrank, its gravitational potential energy was converted to thermal energy. C) Nuclear fusion occurring in the core of the protosun produced energy that heated the nebula. D) As the cloud shrank, its kinetic energy was converted to gravitational potential energy. E) Radiation from other nearby stars that had formed earlier heated the nebula.

B) As the cloud shrank, its gravitational potential energy was converted to thermal energy.

Why does Venus have such a large difference in temperature between its "no atmosphere" temperature and its actual temperature? A) It has a high level of volcanic activity. B) It has a large amount of carbon dioxide in its atmosphere. C) It is so close to the Sun. D) It has a slow rotation.

B) It has a large amount of carbon dioxide in its atmosphere.

The choices below 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 the Moon. Distance from Sun: same as Mars. Rotation rate: once every 10 days. B) Size: twice as big as Earth. Distance from Sun: same as Mercury. Rotation rate: once every 6 months. 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.

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

In light of what you've learned about the formation of our own solar system, decide whether the discovery should be considered reasonable or surprising. A) Reasonable. This is very close to the layout of our solar system B) Surprising. In the process of nebular capture the formation of large number moons at a jovian planet is more likely that at a terrestrial planet.

B) Surprising. In the process of nebular capture the formation of large number moons at a jovian planet is more likely that at a terrestrial planet.

What is the giant impact hypothesis for the origin of the Moon? A) The Moon originally was about the same size as Earth, but a giant impact blasted most of it away so that it ended up much smaller than Earth. B) The Moon formed from material blasted out of the Earth's mantle and crust by the impact of a Mars-size object. C) The Moon formed just like the Earth, from accretion in the solar nebula. D) The Moon formed when two gigantic asteroids collided with one another.

B) The Moon formed from material blasted out of the Earth's mantle and crust by the impact of a Mars-size object.

According to our present theory of solar system formation, which of the following statements about the growth of terrestrial and jovian planets is not true? A) The terrestrial planets formed inside the frost line of the solar nebula and the jovian planets formed beyond it. B) The jovian planets began from planetesimals made only of ice, while the terrestrial planets began from planetesimals made only of rock and metal. C) Both types of planet begun with planetesimals growing through the process of accretion, but only the jovian planets were able to capture hydrogen and helium gas from the solar nebula. C) Swirling disks of gas, like the solar nebula in miniature, formed around the growing jovian planets but not around the growing terrestrial planets.

B) The jovian planets began from planetesimals made only of ice, while the terrestrial planets began from planetesimals made only of rock and metal.

Which of the following is the most basic definition of a greenhouse gas? A) a gas that keeps warm air from rising, and therefore warms the surface B) a gas that absorbs infrared light C) a gas that absorbs visible light D) a gas that reflects infrared light

B) a gas that absorbs infrared light

Which of the following did not occur during the collapse of the solar nebula? A) heating up B) concentrating denser materials nearer the Sun C) spinning faster

B) concentrating denser materials nearer the Sun

Planetary orbits in our solar system are: A) very eccentric (stretched-out) ellipses and in the same plane. B) fairly circular and in the same plane. C) fairly circular but oriented in every direction.

B) fairly circular and in the same plane

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) its size C) its composition D) whether or not it has liquid water

B) its size

Sunsets and sunrises often appear red because A) the cooler atmosphere in the morning and evening absorbs more blue light. B) sunlight must pass through more atmosphere, which scatters the shorter wavelengths more than the longer wavelengths, allowing more red light to reach your eye. C) the Sun emits more red light when it's rising and setting. D) sunlight must pass through more atmosphere, which scatters the longer wavelengths more than the shorter wavelengths, allowing more red light to reach your eye. E) none of the above

B) sunlight must pass through more atmosphere, which scatters the shorter wavelengths more than the longer wavelengths, allowing more red light to reach your eye.

Which of the following best 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 lithosphere by internal stresses D) the wearing down or building up of geological features by wind, water, ice, and other phenomena of planetary weather

B) the eruption of molten rock from a planet's interior to its surface

Which of the following types of material can condense into what we call ice at low temperatures? A) hydrogen and helium B) metal C) hydrogen compounds D) rock

C) hydrogen compounds

According to our theory of solar system formation, why do we find some exceptions to the general rules and patterns of the planets? A) Our theory is not quite correct because it cannot explain these exceptions. B) The exceptions probably represent objects that formed recently, rather than early in the history of the solar system. C) Most of the exceptions are the result of giant impacts or close gravitational encounters. D) The exceptions are probably the result of the Sun passing very close to another star billions of years ago. E) The exceptions probably represent objects that were captured by our solar system from interstellar space.

C) Most of the exceptions are the result of giant impacts or close gravitational encounters.

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) dense metals falling downward while low-density rock rises upward C) Not much-on human time scales, the mantle looks like solid rock. D) hot molten rock rising upward throughout the mantle and cool, solid rock falling downward

C) Not much-on human time scales, the mantle looks like solid rock.

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.

About 2% of our solar nebula consisted of elements heavier than hydrogen and helium. However, the very first generation of stars in the universe probably consisted only of hydrogen and helium. Which of the following statements is most likely to have been true about these first-generation stars? A) They likely had even numbers of terrestrial and jovian planets, like our solar system. B) The nebula in which they formed likely had more hydrogen compounds than the nebula that formed the solar system. C) Planets were likely very rare or non-existent around these first-generation stars. D) They likely had numerous terrestrial planets but no jovian planets.

C) Planets were likely very rare or non-existent around these first-generation stars.

The choices below 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: same as Mars. Distance from Sun: same as Earth. Rotation rate: once every 18 hours. B) Size: same as the Moon. Distance from Sun: same as Mars. Rotation rate: once every 10 days. C) Size: same as Venus. Distance from Sun: same as Mars. Rotation rate: once every 25 hours. D) Size: same size as Earth. Distance from Sun: same as Mercury. Rotation rate: once every 6 months.

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

What makes us think that Mars must once have had an atmosphere that was warmer and thicker? A) We think it for purely theoretical reasons, based on calculations showing that the Sun has brightened with time. B) The presence of inactive volcanoes on Mars tells us that there must once have been a lot of outgassing, and hence a thicker atmosphere. C) The atmosphere is too cold and thin for liquid water today, yet we see evidence that water flowed on the surface in the past. D) The fact that parts of Mars have a lot of craters tells us that Mars must once have been much warmer.

C) The atmosphere is too cold and thin for liquid water today, yet we see evidence that water flowed on the surface in the past.

What do meteorites reveal about the solar system? A) They reveal that the early solar system consisted mostly of hydrogen and helium gas. B) They reveal that the solar system once contained 10 planets. C) They reveal that the age of the solar system is approximately 4.6 billion years. D) Nothing, because they come from other star systems. E) They reveal that meteorites are about the same age as most Earth rocks.

C) They reveal that the age of the solar system is approximately 4.6 billion years.

Which of the following best explain what we think happened to outgassed water vapor on Venus? A) It is frozen as water ice in craters near the poles. B) It turned into carbon dioxide by reacting with nitrogen in Venus's atmosphere. C) Ultraviolet light split the water molecules, and the hydrogen then escaped to space. D) Water was removed from the atmosphere by chemical reactions with surface rock.

C) Ultraviolet light split the water molecules, and the hydrogen then escaped to space.

What do we mean when we say that the terrestrial worlds underwent differentiation? A) The five terrestrial worlds all started similarly but ended up looking quite different. B) Their surfaces show a variety of different geological features resulting from different geological processes. C) When their interiors were molten, denser materials sank toward their centers and lighter materials rose toward their surfaces. D) They lost interior heat to outer space.

C) When their interiors were molten, denser materials sank toward their centers and lighter materials rose toward their surfaces.

Suppose you start with 1 kilogram of a radioactive substance that has a half-life of 10 years. Which of the following statements will be true after 20 years pass? A) You'll have 0.5 kilogram of the radioactive substance remaining. B) All the material will have completely decayed. C) You'll have 0.25 kilogram of the radioactive substance remaining. D) You'll have 0.75 kilogram of the radioactive substance remaining.

C) You'll have 0.25 kilogram of the radioactive substance remaining.

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

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

Why is the sky blue (on Earth)? A) because deep space is blue in color B) because molecules scatter red light more effectively than blue light C) because molecules scatter blue light more effectively than red light D) because the Sun emits mostly blue light E) No one knows-this is one of the great mysteries of science.

C) because molecules scatter blue light more effectively than red light

What are greenhouse gases? A) gases that transmit visible light B) gases that absorb ultraviolet light C) gases that absorb infrared light D) gases that absorb visible light E) gases that transmit infrared light

C) gases that absorb infrared light

The composition of the solar nebula was 98% A) rock and metal. B) hydrogen compounds. C) hydrogen and helium.

C) hydrogen and helium

Which of the following is not evidence supporting the idea that our Moon formed as a result of a giant impact? A) The Moon has a much smaller proportion of easily vaporized materials than Earth. B) Computer simulations show that the Moon could really have formed in this way. C) The Moon's average density suggests it is made of rock much more like that of the Earth's outer layers than that of the Earth as a whole. D) The Pacific Ocean appears to be a large crater-probably the one made by the giant impact.

D) The Pacific Ocean appears to be a large crater-probably the one made by the giant impact.

Which of the following observations of an extrasolar planet system would be inconsistent with the nebular theory of planet formation? A) a system in which the planets rotate in the same direction as they orbit B) a system which has two terrestrial planets close in and two gas giants farther out C) a system in which some planets have small moons orbiting in a direction opposite to the planet's rotation D) a system in which all the planets orbit in completely different planes

D) a system in which all the planets orbit in completely different planes

Which of the following are relatively unchanged fragments from the early period of planet building in the solar system? A) asteroids B) Kuiper belt comets C) Oort cloud comets D) all of the above

D) all of the above

According to our present theory of solar system formation, why were solid planetesimals able to grow larger in the outer solar system than in the inner solar system? A) because gas in the outer solar system contained a larger proportion of rock, metal, and hydrogen compounds than the gas in the inner solar system B) because only the outer planets captured hydrogen and helium gas from the solar nebula C) because the Sun's gravity was stronger in the outer solar system, allowing more solid material to collect D) because only metal and rock could condense in the inner solar system, while ice also condensed in the outer solar system

D) because only metal and rock could condense in the inner solar system, while ice also condensed in the outer solar system

Volcanism is more likely on a planet that A) doesn't have an atmosphere or oceans. B) is closer to the Sun. C) is struck often by meteors and solar system debris. D) has high internal temperatures.

D) has high internal temperatures.

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.

D) high internal temperature.

The processes responsible for all surface geology on the terrestrial planets are ________. A) accretion, differentiation, and radioactive decay B) eruptions, lava flows, and outgassing C) convection, conduction, and radiation D) impact cratering, volcanisms, tectonics, and erosion

D) impact cratering, volcanisms, tectonics, and erosion

Which of the following is not an example of tectonics? A) the slow movement of Earth's lithospheric plates B) the formation of a cliff when the lithosphere shrinks C) the stretching of the crust by underlying mantle convection D) the gradual disappearance of a crater rim as a result of wind and rain

D) the gradual disappearance of a crater rim as a result of wind and rain

Which of the following best 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 lithosphere by internal stresses 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 does the Sun's mass compare with that of the planets? A) It is about a hundred times more massive than all the planets combined. B) It is about a hundred times more massive than Earth. C) It is about as massive as all the planets combined. D) It is about a thousand times more massive than Earth. E) It is about a thousand times more massive than all the planets combined.

E) It is about a thousand times more massive than all the planets combined.

According to our theory of solar system formation, why do all the planets orbit the Sun in the same direction and in nearly the same plane? A) The original solar nebula happened to be disk-shaped. B) We would expect that a very small fraction of all planetary systems would have planets orbiting in such a pattern, so ours turned out that way due to random chance. C) The Sun formed first, and as it grew in size it spread into a disk, rather like the way a ball of dough can be flattened into a pizza by spinning it. D) Any planets that once orbited in the opposite direction or a different plane were ejected from the solar system. E) The laws of conservation of energy and conservation of angular momentum ensure that any rotating, collapsing cloud will end up as a spinning disk.

E) The laws of conservation of energy and conservation of angular momentum ensure that any rotating, collapsing cloud will end up as a spinning disk.

Which of the following is not a characteristic of the outer planets? A) They have rings. B) Their orbits are separated by relatively large distances. C) They are primarily made of hydrogen, helium, and hydrogen compounds. D) They have thick atmospheres. E) They have relatively high densities.

E) They have relatively high densities.

What kind of surface features may result from tectonics? A) valleys B) cliffs C) mountains D) volcanos E) all of the above

E) all of the above

What is the main reason that Mars, compared to Earth, has become so geologically inactive? A) its composition B) its distance from the Sun C) its tilt D) its rotation rate E) its size

E) its size

Which of the following gases best absorbs ultraviolet light? A) oxygen B) hydrogen C) nitrogen D) carbon dioxide E) ozone

E) ozone

All the planets in the solar system have at least one moon. TRUE or FALSE?

False

All the planets in the solar system rotate (spin) in the same direction as they orbit the Sun. TRUE or FALSE?

False

A key clue to how the solar system formed is the observation that all the planets orbit close to the same plane. TRUE or FALSE?

True

Based on our theory of how our own solar system formed, we would expect that other solar systems would be quite common. TRUE or FALSE?

True

Most of Earth's water likely resulted from impacts with icy planetesimals that originated in the outer regions of the solar system. TRUE or FALSE?

True

Outside the frost line, planetesimals could form into larger objects due to the presence of both rock and ice. TRUE or FALSE?

True

The more massive planets in the solar system tend to be less dense than the lower mass planets. TRUE or FALSE?

True

Without greenhouse gases, water on Earth's surface would be completely frozen. TRUE or FALSE?

True