AST 3
What is the likely origin of Earth's water and organic compounds? a) Ice and organic grains that formed within 1 AU b) Comets c) Venus d) Mercury e) Cosmic rays
B
What is the longest-lasting internal heat source responsible for geological activity? a) accretion b) radioactive decay c) sunlight
B
What is the primary reason that astronomers suspect that some jovian moons were captured into their current orbits? a) Some moons have a composition that differs from the composition of the planets. b) Some moons have orbits that are backward (compared to their planet's rotation) or highly inclined to their planet's equator. c) Astronomers have observed moons being captured. d) Some moons are surprisingly large in size.
B
What process created the elements from which the terrestrial planets were made? a) the Big Bang b) nuclear fusion in stars c) chemical processes in interstellar clouds d) their origin is unknown.
B
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
What are the two geological features that appear to set Earth apart from all the other terrestrial worlds? a) mantle convection and a thick atmosphere b) shield volcanoes and plate tectonics c) plate tectonics and widespread erosion d) significant volcanism and tectonics
C
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
What feature of Venusian geology is largely unexplained? a) It lacks substantial erosion. b) It has fewer impact craters. c) It lacks plate tectonics. d) None of the above; we understand each of these features.
C
Which internal heat source still generates heat within the terrestrial worlds today? a) Heat of accretion. b) Heat from differentiation c) Heat from radioactive decay. d) Heat from convection.
C
Which jovian planet does NOT have rings? a) Jupiter b) Neptune c) All the jovian planets have rings. d) Uranus
C
Which lunar features best indicate past fluid flow (molten material) on the lunar surface? a) craters b) rays c) maria d) mountains e) cliffs
C
Which of the following best describes the lunar maria? a) mountainous regions on the Moon b) densely cratered regions on the Moon c) relatively smooth, flat plains on the Moon d) frozen oceans of liquid water on the Moon
C
A common natural example of a gas condensing into a solid is a) Water freezing b) Water evaporating c) Water ice sublimation d) Frost e) Dry ice evaporating
D
Compared to the distance between Earth and Mars, the distance between Jupiter and Saturn is ______. a) just slightly less b) much smaller c) about the same d) much larger
D
According to our modern science, which of the following best explains why the vast majority of the mass of our solar system consists of hydrogen and helium gas? a) Hydrogen and helium are the most common elements throughout the universe because they were the only elements present when the universe was young. b) All the other elements escaped from the solar nebula before the Sun and planets formed. c) All the other elements were swept out of the solar system by the solar wind. d) Hydrogen and helium are produced in stars by nuclear fusion.
A
According to our theory of solar system formation, which law best explains why the central regions of the solar nebula got hotter as the nebula shrank in size? a) The law of conservation of energy b) The two laws of thermal radiation c) Newton's third law d) The law of conservation of angular momentum
A
According to present understanding, which of the following statements about the solar wind is not true? a) It is even stronger today than it was when the Sun was young. b) It consists of charged particles blown off the surface of the Sun. c) It helped in the transfer of angular momentum from the young Sun to particles that blew into interstellar space, which explains why the Sun rotates so slowly today. d) It swept vast amounts of gas from the solar nebula into interstellar space.
A
Based on everything we have learned about Venus and Mars, what is the most surprising aspect of Earth's climate history? a) the fact that the temperature of our planet has remained relatively steady throughout our planet's history b) the fact that Earth apparently got a lot of atmospheric gas from outgassing by volcanoes c) the fact that Earth's climate can be affected by changes in its axis tilt d) the fact that Earth had enough water to form oceans
A
Based on our current theory of Earth's formation, the water we drink comes from a) comets that impacted Earth. b) chemical reactions that occurred in Earth's core after Earth formed. c) material left behind during the giant impact that formed the Moon. d) ice that condensed in the solar nebula in the region where Earth formed. e) chemical reactions that occurred in Earth's crust after Earth formed.
A
How do scientists determine the age of the solar system? a) Radiometric dating of meteorites b) Radiometric dating of the oldest Earth rocks. c) Radiometric dating of Moon rocks. d) Theoretical calculations tell us how long it has taken the planets to evolve to their present forms
A
How is Einstein's famous equation, E = mc2, important in understanding the Sun? a) It explains the fact that the Sun generates energy to shine by losing some 4 million tons of mass each day. b) It explains why the Sun has a magnetic field strong enough influence the atmospheres of the planets. c) It explains why the Sun's surface temperature is about 6,000°C. d) It explains why the Sun is so massive.
A
How would the solar system be different if the solar nebula had cooled, with a temperature half its actual value? a) Jovian planets would have formed closer to Sun. b) There would be no asteroids. c) There would be no comets. d) Terrestrial planets would be larger.
A
Imagine that an alien spaceship crashed onto Earth. Which statement would most likely be true? a) It would crash in the ocean. b) All the evidence of the crash would be quickly whisked off by the U.S. military to Area 51 in Nevada. c) The aliens' home world is another planet in our own solar system. d) The crash would create a noticeable crater.
A
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
In the context of plate tectonics, what is a subduction zone? a) a place where a seafloor plate is sliding under a continental plate b) a place where two plates are slipping sideways against one another c) a place where two plates are pulling apart d) a place where two continental plates are colliding
A
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) On human time scales, the mantle looks like solid rock, so not much would be seen. b) a rapid, up and down churning of the material in the mantle c) Hot molten rock rising upward throughout the mantle and cool, solid rock falling downward. d) Dense metals falling downward and low-density rock rising upward.
A
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: twice as big as Earth. Distance from Sun: same as Mercury. Rotation rate: once every 6 months. b) Size: same as Mars. Distance from Sun: same as Earth. Rotation rate: once every 18 hours. 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.
A
The following statements are all true. Which one counts as an "exception to the rule" in being unusual for our solar system? a) The diameter of Earth's Moon is about 1/4 that of Earth. b) Saturn has no solid surface. c) Venus does not have a moon. d) Jupiter has a small axis tilt.
A
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
The region of our solar system between Mercury and Mars has few asteroids, whereas the region between Mars and Jupiter has many asteroids. Based on what you have learned, what is the most likely explanation for the lack of asteroids between Mercury and Mars? a) There were few planetary leftovers in this region because most of the solid material was accreted by the terrestrial planets as the planets formed. b) All the asteroids that formed between Mercury and Mars later migrated to the asteroid belt between Mars and Jupiter. c) Gravity was too weak to allow asteroids to form in this part of the solar system. d) It was too hot for asteroids to form in this part of the solar system.
A
Which two factors are most important to the existence of plate tectonics on Earth? a) mantle convection and a thin lithosphere b) oxygen in the atmosphere and mantle convection c) Earth's liquid outer core and solid inner core d) the existence of life and oxygen in the atmosphere
A
The solar system has two types of planets, terrestrial and jovian. According to the nebular theory, why did terrestrial planets form in the inner solar system and jovian planets in the outer solar system? a) Ices condensed only in the outer solar system, where some icy planetesimals grew large enough to attract gas from the nebula, while only metal and rock condensed in the inner solar system, making terrestrial planets. b) All the planets started out large, but the Sun's heat evaporated so much material that the inner planets ended up much smaller. c) After the planets formed, the Sun's gravity pulled the dense terrestrial planets inward, leaving only jovian planets in the outer solar system. d) Denser particles of rock and metal sank into the inner solar system, leaving only gases in the outer solar system.
A
What are the basic requirements for a terrestrial world to have a global magnetic field? a) a core layer of molten, convecting material and sufficiently rapid rotation b) a core that has a molten layer and a mantle that has convection c) a metal core, a rocky mantle, and sufficiently rapid rotation d) a metal core and rapid rotation
A
What do we mean by the frost line when we discuss the formation of planets in the solar nebula? a) It is a circle at a particular distance from the Sun, beyond which the temperature was low enough for ices to condense. b) 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 the altitude in a planet's atmosphere at which snow can form. d) It is another way of stating the temperature at which water freezes into ice.
A
What important change in the Sun over the past four billion years is thought to be very important to understanding the climates of Venus, Earth, and Mars? a) a gradual brightening with time b) a gradual dimming with time c) a gradual reduction in the amount of ultraviolet and X-ray radiation coming from the Sun d) a gradual weakening of the solar wind with time
A
What is the importance of the carbon dioxide (CO2) cycle? a) It regulates the carbon dioxide concentration of our atmosphere, keeping temperatures moderate. b) It makes the growth of continents possible. c) It will prevent us from suffering any consequences from global warming. d) It allows for an ultraviolet-absorbing stratosphere.
A
What is the primary basis on which we divide the ingredients of the solar nebula into four categories (hydrogen/helium; hydrogen compound; rock; and metal)? a) The temperatures at which various materials will condense from gaseous form to solid form. b) The atomic mass numbers of various materials. c) The locations of various materials in the solar nebula. d) The amounts of energy required to ionize various materials.
A
What process has shaped Earth's surface more than any other? a) plate tectonics b) impact cratering c) acid rain d) erosion e) volcanism
A
What substances existed as solid flakes within the innermost regions (within about the inner 0.3 AU) of the solar system before planets began to form? a) none b) only rocks and metals c) only hydrogen compounds d) only hydrogen and helium gases
A
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
Which of the following best describes the nature and origin of the atmospheres of the Moon and Mercury? a) They have thin exospheres only, with gas coming from impacts of subatomic particles and photons. b) They have thin tropospheres only, with gas coming from evaporation and sublimation. c) They have only small amounts of gas, all of which is left over from outgassing long ago. d) They have very thin atmospheres produced by outgassing but still have the layers of a troposphere, thermosphere, and exosphere.
A
Which of the following general statements about light and Earth's atmosphere is NOT true? a) Visible light from the Sun is absorbed in the exosphere. b) Infrared light emitted by Earth itself is absorbed in the troposphere. c) X rays from the Sun are absorbed in the thermosphere. d) Ultraviolet from the Sun is absorbed in the stratosphere.
A
Which of the following is NOT an example of tectonics? a) the gradual disappearance of a crater rim as a result of wind and rain b) the stretching of the crust by underlying mantle convection c) the formation of a cliff when the lithosphere shrinks d) the slow movement of Earth's lithospheric plates
A
Which of the following is the most basic definition of a greenhouse gas? a) a gas that absorbs infrared light b) a gas that makes a planet much hotter than it would be otherwise, even in small amounts c) a gas that reflects a lot of sunlight d) a gas that keeps warm air from rising, and therefore warms the surface
A
Which of the following is the origin of almost all the large moons around the jovian planets? a) They were formed by condensation and accretion in a disk of gas around the planet. b) They are captured asteroids. c) They are captured comets. d) They are captured planets. e) They were formed by giant impacts.
A
Which of the following most likely explains why Venus does not have a global magnetic field like Earth? a) Its rotation is too slow. b) It has too thick of an atmosphere. c) It does not have a metallic core. d) Unlike Earth, Venus does not have a liquid outer core.
A
Why is the sky blue (on Earth)? a) because molecules scatter blue light more effectively than red light b) because deep space is blue in color c) because molecules scatter red light more effectively than blue light. d) because the Sun emits mostly blue light e) No one knows—this is one of the great mysteries of science.
A
Why was it advantageous for the Voyager mission to consist of flybys rather than orbiters? a) Each individual spacecraft was able to visit more than one planet. b) Spacecraft making flybys can return to Earth more quickly than orbiters. c) Flyby spacecraft can get closer to a planet than an orbiting spacecraft. d) It was easier for data to be radioed back to Earth with flybys than orbiters.
A
According to modern scientific dating techniques, approximately how old is the solar system? a) 4.6 million years b) 4.5 billion years c) 10,000 years d) 14 billion years
B
According to our present theory of solar system formation, which of the following best explains why the solar nebula ended up with a disk shape as it collapsed? a) The force of gravity pulled the material downward into a flat disk. b) It flattened as a natural consequence of collisions between particles in the nebula. c) It was fairly flat to begin with, and retained this flat shape as it collapsed. d) The law of conservation of energy.
B
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 universal gravitation b) The law of conservation of angular momentum c) Einstein's law E = mc2 d) The law of conservation of energy
B
Assuming that other planetary systems form in the same way as our solar system formed, where would you expect to find terrestrial planets? a) Terrestrial planets will likely be located farther from the planetary system's star than any jovian planets. b) Terrestrial planets will likely be located nearer the planetary system's star than any jovian planets. c) There is no way to know where terrestrial planets are likely to be.
B
Compared to terrestrial planets, jovian planets are __________. a) more massive and higher in average density b) more massive and lower in average density c) less massive and lower in average density d) less massive and higher in average density
B
From high to low, rank the following objects in the average density: a) Mars, Earth, Sun, Saturn b) Earth, Mars, Sun, Saturn c) Earth, Mars, Saturn, Sun d) Mars, Earth, Saturn, Sun e) Sun, Mars, Earth, Saturn
B
Heat escapes from a planet's surface into space by thermal radiation. Planets radiate almost entirely in the wavelength range of the a) visible. b) infrared. c) radio. d) ultraviolet. e) none of the above
B
How do we know what the interior structure of the Earth is like? a) We have drilled deep holes that penetrate nearly to the core. b) Sound waves travel through the Earth and probe the interior. c) X-ray travel through the Earth and probe the interior. d) Mysterious particles called neutrinos penetrate through the Earth and probe the interior. e) The interior structure is based on theories, but has not been observed. f) Twitter & Facebook ?
B
Large moons orbit their planets in the same direction the planet rotates: a) half of the time. b) most of the time. c) rarely.
B
Most of mass in the solar system is in ______; Most of angular momentum in the solar system is in _____ a) Sun; Sun b) Sun; Planets c) Planets; Sun d) Planets; Planets
B
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 rotates much slower than Earth. b) Marsʹs interior has cooled so much its molten core layer no longer undergoes convection. c) The Martian core is made of rock, while Earthʹs core is made of metal. d) Mars is too far from the Sun to have a global magnetic field.
B
Suppose that Earth's atmosphere had no greenhouse gases. Then Earth's average surface temperature would be _______. a) about the same as it is now b) well below the freezing point of water c) slightly warmer, but still well below the boiling point of water d) slightly cooler, but still above freezing
B
Suppose you find a rock that contains 10 micrograms of radioactive potassium-40, which has a half-life of 1.25 billion years. By measuring the amount of its decay product (argon-40) present in the rock, you conclude that there must have been 80 micrograms of potassium-40 when the rock solidified. How old is the rock? a) 2.5 billion years b) 3.75 billion years c) 1.25 billion years d) 5.0 billion years
B
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) You'll have 0.25 kilogram of the radioactive substance remaining. c) All the material will have completely decayed. d) You'll have 0.75 kilogram of the radioactive substance remaining.
B
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: same as Mars. Distance from Sun: same as Earth. Rotation rate: once every 18 hours. b) Size: same as Venus. Distance from Sun: same as Mars. Rotation rate: once every 25 hours. c) Size: same as the Moon. Distance from Sun: same as Mars. Rotation rate: once every 10 days. d) Size: twice as big as Earth. Distance from Sun: same as Mercury. Rotation rate: once every 6 months.
B
The cores of the terrestrial worlds are made mostly of metal because ______. a) over billions of years, convection gradually brought dense metals downward to the core b) metals sunk to the centers a long time ago when the interiors were molten throughout c) the core contained lots of radioactive elements that decayed into metals d) the terrestrial worlds as a whole are made mostly of metal
B
The most abundant ingredient of the Sun and Jupiter is: a) ionized metal. b) hydrogen. c) ammonia.
B
The nebular theory also predicts that the cloud will flatten into a disk as it shrinks in size. Which of the following best explains why the collapsing cloud should form a disk? a) All collapsing objects tend to flatten into a disk, regardless of their rotation. b) Colliding cloud particles exchange angular momentum and, on average, end up with the rotation pattern for the cloud as a whole. c) Gravity pulls more strongly on material along the rotation axis than perpendicular to it, bringing this material downward into a disk. d) As a star forms near the cloud center, its wind blows away material that is not aligned with its equator, thereby leaving an equatorial disk of material.
B
What's the fundamental reason that Mars has so little geological activity compared to Earth? a) its rapid rotation compared to the Earth b) its small size compared to Earth c) its farther distance than Earth to the Sun d) its large size compared to the Earth e) its slow rotation compared to the Earth f) its closer distance than Earth to the Sun
B
When differentiation occurs, the average density of a terrestrial planet a) will increase. b) will stay the same. c) will decrease. d) cannot be evaluated with this information.
B
Where would you expect terrestrial planets to form in the solar nebula? a) within the innermost regions (within about the inner 0.3 AU) b) anywhere between the innermost regions (within about the inner 0.3 AU) and the frost line c) anywhere outside the innermost regions (within about the inner 0.3 AU) d) anywhere outside the frost line
B
Which describes our understanding of flowing water on Mars? a) It was never important. b) It was important once, but no longer. c) It is a major process on the Martian surface today.
B
Which of the following best describes the geological histories of the Moon and Mercury? a) 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. c) All four geological processes were important in their early histories, but only impact cratering still reshapes their surfaces today. d) Impact cratering is the only major geological process that has affected their surfaces.
B
Which of the following correctly lists the terrestrial worlds in order from the thickest atmosphere to the thinnest atmosphere? (Note: Mercury and the Moon are considered together in this question.) a) Earth, Venus, Mars, Moon/Mercury b) Venus, Earth, Mars, Moon/Mercury c) Venus, Mars, Moon/Mercury, Earth d) Mars, Venus, Earth, Moon/Mercury
B
Which of the following has the same chemical composition like our Sun? a) Terrestrial planets b) Jovian planets c) Donald Trump d) Barack Obama
B
Which of the following is NOT an expected consequence of global warming? a) melting of polar ice and glaciers b) warming up of the entire Earth by the same amount c) an increase in the severity of winter blizzards d) an increase in the number and intensity of hurricanes
B
Which of the following is correct? a) The rotation axes of planets are perpendicular to their orbital plane (the ecliptic). b) No planet's orbital inclination is more than 20 degrees from the ecliptic. c) Planets orbits are circular. d) Planets always rotate and revolve in the same direction.
B
Which of the following is not a characteristic of jovian planets? a) They all have many moons. b) They have a higher overall density than terrestrial planets. c) They are larger than terrestrial planets. d) They are farther from the Sun and farther apart from each other than the terrestrial planets. e) They have deep atmospheres made of hydrogen, helium, and hydrogen compounds.
B
Which of the following is not a real difference between asteroids and comets? a) Asteroids are made mostly of rock and comets are made mostly of ice. b) Asteroids orbit the Sun while comets just float randomly around in the Oort cloud. c) Most asteroids are located much nearer to the Sun than most comets. d) It is thought that comets are far more numerous than asteroids.
B
Which of the following is not a real difference between asteroids and comets? a) It is thought that comets are far more numerous than asteroids. b) Asteroids orbit the Sun, whereas comets just float randomly around in the Oort cloud. c) Asteroids are made mostly of rock and comets are made mostly of ice. d) Most asteroids are located much nearer to the Sun than most comets.
B
Which of the following is the underlying reason why Venus has so little wind erosion? a) its small size b) its slow rotation c) its relatively close distance to the Sun d) its thick atmosphere
B
Which of the following statements about the object called Eris is not true? a) It is slightly larger in mass than Pluto. b) It is thought to be the first example of a new class of object. c) It orbits the Sun in the same general direction as the planets. d) It lies well beyond Pluto and Neptune.
B
Which planet listed below has the most extreme seasons? a) Jupiter b) Uranus c) Mars d) Venus e) Mercury
B
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
Why are terrestrial planets denser than jovian planets? a) Actually, the jovian planets are denser than the terrestrial planets. b) The terrestrial planets formed in the inner solar nebula, where only dense materials could condense. c) Gravity compresses terrestrial planets to a higher degree, making them denser. d) The Sun's gravity gathered dense materials into the inner solar system.
B
Why are there fewer large impact craters on the Earth's seafloor than on the continents? a) The oceans slow large impactors and prevent them from making craters. b) Seafloor crust is younger than continental crust, so it has had less time in which to suffer impacts. c) Erosion erases impact craters must faster on the ocean bottom than on land. d) Most impacts occur on the land.
B
Why could the jovian planets grow to be much larger than the terrestrial planets? a) They were farther from the Sun, where gravity was weaker. b) They formed beyond the frost linewhere ices could condense, so they included hydrogen compounds. c) They were far enough from the Sun to escape the heavy bombardmentthat battered the early solar system.
B
Why is Earth's continental crust lower in density than seafloor crust? a) Continental crust is made from a low-density volcanic rock called basalt. b) Continental crust is made as the lowest-density seafloor crust melts and erupts to the surface near subduction zones. c) Continental crust comes from volcanoes, whereas seafloor crust comes from geysers. d) Continental crust comes from Earth's inner core, whereas seafloor crust comes from the outer core.
B
Are there any exceptions to the rule that planets rotate with small axis tilts and in the same direction that they orbit the Sun? a) No. b) Venus is the only exception. c) Venus and Uranus are exceptions.
C
Assuming that features you see on Mars are similar to features found on Earth, what would a casual inspection of the interactive photo of Mars lead you to suspect about water on Mars? a) Abundant surface water is found in large, brownish pools inside craters. b) There are numerous small streams flowing with water. c) Surface water only exists as frozen ice. d) No surface water currently exists in any form.
C
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) whether or not it has liquid water b) its distance from the Sun c) its size d) its composition
C
In what way is Venus most similar to Earth? a) Both planets have similar atmospheres. b) Both planets have warm days and cool nights. c) Both planets are nearly the same size. d) Both planets have similar surface geology.
C
Many meteorites appear to have formed early in the solar system's history. How do these meteorites support our theory about how the terrestrial planets formed? a) The meteorites sizes are just what we'd expect if metal and rock condensed and accreted as our theory suggests. b) Their overall composition is just what we believe the composition of the solar nebula to have been: mostly hydrogen and helium. c) The meteorites appearance and composition is just what we'd expect if metal and rock condensed and accreted as our theory suggests. d) Their appearance and composition matches what we observe in comets today, suggesting that they were once pieces of icy planetesimals.
C
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 rotates much slower than the Earth. b) Mars is too far from the Sun to have a global magnetic field. c) Mars's interior has cooled so much that its molten core layer no longer undergoes convection. d) The Martian core is made of rock, whereas Earth's core is made of metal.
C
The Earth has far less identifiable large impact craters than the Moon, because a) The Moon protects the Earth from impactors. b) The Earth has an atmosphere and most impactors burn up before they hit the ground. c) The Earth has erosion and active geology which reforms the surface. d) The Moon is closer to the source of impactors.
C
The jovian planets are thought to have formed as gravity drew hydrogen and helium gas around planetesimals made of __________. a) only rocks and metals b) only ices c) rocks, metals, and ices d) rocks, metals, ices, and hydrogen and helium gases
C
The major processes that heat the interiors of the terrestrial worlds are __________. a) (1) heat of accretion; (2) heat from convection; (3) heat from thermal radiation b) (1) volcanism; (2) tectonics; (3) erosion c) (1) heat deposited as the planets were built from planetesimals; (2) heat deposited as the planets underwent differentiation; (3) heat released by radioactive decay d) (1) heat deposited as the planets were built from planetesimals; (2) heat of accretion; (3) heat that came from the gravitational potential energy of incoming planetesimals
C
The planet in our solar system with the highest average surface temperature is __________. a) Mercury b) Earth c) Venus d) Neptune
C
Which of the following best explains why we can rule out the idea that planets are usually formed by near collisions between stars? a) Studies of the trajectories of nearby stars relative to the Sun show that the Sun is not in danger of a near collision with any of them. b) A near collision might have created planets, but it could not have created moons, asteroids, or comets. c) Stellar near collisions are far too rare to explain all the planets now known to orbit nearby stars. d) A near collision should have left a trail of gas extending out behind the Sun, and we see no evidence of such a trail.
C
Which of the following is a characteristic of a dwarf planet? a) A dwarf planet must be in the Kuiper Belt. b) A dwarf planet cannot have any moons. c) A dwarf planet must be round. d) all of the above
C
Which of the following statements about Pluto is true? a) It is orbited by only one moon. b) It is the largest known object that is considered to be a dwarf planet. c) It has more in common with comets in the Kuiper belt than it does with terrestrial planets like Earth. d) Its mass is a little less than Earth's mass.
C
Which of the following types of material can condense into what we call ice at low temperatures? a) metal b) rock c) hydrogen compounds d) hydrogen and helium
C
Which planet listed has the most extreme seasons? a) Jupiter b) Mars c) Uranus d) Earth
C
Which terrestrial planets have had volcanic activity at some point in their histories? a) only Earth b) Earth and Mars c) all of them
C
Why did the solar nebula heat up as it collapsed? a) Nuclear fusion occurring in the core of the protosun produced energy that heated the nebula. b) Radiation from other nearby stars that had formed earlier heated the nebula. c) As the cloud shrank, its gravitational potential energy was converted to kinetic energy and then into thermal energy. d) The shock wave from a nearby supernova heated the gas. e) Collisions among planetesimals generated friction and heat.
C
Why has NASA sent recent orbiters to Mars on trajectories that required them to skim through Mars's atmosphere before settling into their final orbits? a) Each spacecraft also carried a lander, and the lander could only be dropped to the Martian surface when the spacecraft passed through the atmosphere. b) It allowed the orbiters to get higher resolution pictures of the surface as it came close when skimming through the atmosphere. c) It saves money because the spacecraft uses atmospheric drag to slow down rather than needing to carry enough fuel to slow by firing rocket engines. d) It allowed the spacecraft to collect samples of the atmospheric gas for return to Earth.
C
You discover an impact crater that is 10 kilometers across. Which of the following can you conclude? a) It was created by the impact of an object about 100 kilometers across. b) It was created within the past 10 million years. c) It was created by the impact of an object about 1 kilometer across. d) It was created by the impact of an object about 10 kilometers across. e) It was created within the past 1 billion years.
C
About 2% of our solar nebula consisted of elements besides hydrogen and helium. However, the first generation of star systems 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 star systems? a) Jovian planets in these first-generation star systems had clouds made of water and other hydrogen compounds. b) These first-generation star systems typically had several terrestrial planets in addition to jovian planets. c) Like the jovian planets in our solar system, the jovian planets in these first-generation systems were orbited by rings. d) There were no comets or asteroids in these first-generation star systems.
D
According to our present theory of solar system formation, how did Earth end up with enough water to make oceans? a) Earth formed in the relatively narrow region of the solar nebular in which liquid water was plentiful. b) The water was mixed in the other materials in the planetesimals that accreted at our distance from the Sun. c) The water was formed by chemical reactions among the minerals in the Earth's core. d) The water was brought to the forming Earth by planetesimals that accreted beyond the orbit of Mars.
D
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) Swirling disks of gas, like the solar nebula in miniature, formed around the growing jovian planets but not around the growing terrestrial planets. b) 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) The terrestrial planets formed inside the frost line of the solar nebula and the jovian planets formed beyond it. d) The jovian planets began from planetesimals made only of ice, whereas the terrestrial planets began from planetesimals made only of rock and metal.
D
According to our theory of solar system formation, what are asteroids and comets? a) chunks of rock or ice that were expelled from planets by volcanoes b) the shattered remains of collisions between planets c) chunks of rock or ice that condensed after the planets and moons finished forming d) leftover planetesimals that never accreted into planets
D
According to our theory of solar system formation, what three major changes occurred in the solar nebula as it shrank in size? a) Its mass, temperature, and density all increased. 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) Its mass did NOT increase. d) It got hotter, its rate of rotation increased, and it flattened into a disk.
D
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's largest features are three elevated regions that look somewhat like continents. d) Venus has relatively few impact craters and these craters are distributed fairly evenly over the entire planet.
D
Among Earth, Mars, Mercury and Pluto, _________ should cool the fastest and ________ should cool the slowest. a) Mercury, Earth b) Mars, Earth c) Earth, Pluto d) Pluto, Earth e) Earth, Mercury
D
As you've seen, the nebular theory predicts that a cloud that gives birth to planets should have the shape of a spinning disk. Which observable property of our solar system supports this prediction? a) The four largest planets all have disk-shaped ring systems around them. b) The orbit of Earth's Moon lies very close to the ecliptic plane. c) There are two basic types of planets in our solar system: terrestrial and jovian. d) All the planets orbit the Sun in the same direction and in nearly the same plane.
D
Based on its surface features, the most important event on Venus in the past billion years or so was _______. a) the impact of an unusually large asteroid that left a deep scar on one side of the planet b) the eruption of a giant volcano that formed one of Venus's "continents" c) the onset of mantle convection, which caused Venus's lithosphere to split into plates like those on Earth d) a global "repaving" that erased essentially all the surface features that had existed earlier
D
Consider the following statement: "Rocky asteroids are found primarily in the asteroid belt and Kuiper belt, whereas icy comets are found primarily in the Oort cloud." What's wrong with this statement? a) Asteroids are not really made of rock. b) The Oort cloud has nothing to do with comets. c) Comets are not really icy. d) The Kuiper belt contains icy comets, not rocky asteroids. e) The statement is accurate as written.
D
Could a solar system like our have formed with the first generation of stars after the Big Bang? a) No, there would not have been enough time to form planets. b) No, the expansion of the universe would have torn the solar system apart. c) Possibly- there is no physical reason why not. d) No, there would not have been enough metals and rock to form terrestrial planets.
D
Could a solar system like ours have formed with the first generation of stars after the Big Bang? a) Possibly -there is no physical reason why not. b) No, there would not have been enough time to form planets. c) No, the expansion of the universe would have torn the solar system apart. d) No, there would not have been enough metals and rock to form terrestrial planets.
D
From center to surface, which of the following correctly lists the interior layers of a terrestrial world? a) mantle, crust, core b) mantle, core, crust c) core, crust, lithosphere d) core, mantle, crust
D
In the movie Avatar, the home world of Na'vi, Pandora is a moon of the gas giant planet Polyphemusa around Alpha Centauri system. The geology of Pandora is strongly affected by the presence of unobtanium, a mineral whose superconductive properties allow it to float in magnetic fields. To have a significant magnetic field, Pandora needs to have a) convection inside b) molten, electrically conducting interior c) moderately rapid rotation d) all of the above e) B and C
D
In what way is Pluto more like a comet than a planet? a) It has a long tail. b) It has moons. c) It sometimes enters the inner solar system. d) It is made mostly of rock and ice.
D
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 slow rotation of Venus. b) The smaller size of Venus, which has allowed it to lose much more internal heat than Earth. c) The apparent lack of plate tectonics on Venus. d) The high surface temperature that has "baked out" all the liquid water from Venus's crust and mantle.
D
Mars has two moons that are most similar in character to ____________________. a) Earth's Moon b) particles in the rings of Saturn c) comets d) small asteroids
D
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) Erosion affects the maria more than it affects other regions of the Moon. c) The maria formed within the past 1 billion years. d) The maria formed after the heavy bombardment ended.
D
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
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) Mercuryʹs atmosphere prevented smaller objects from hitting the surface. c) only very large impactors hit Mercuryʹs surface in the past. d) the Caloris Basin formed toward the end of the solar systemʹs period of heavy bombardment. e) the Caloris Basin was formed by a volcano.
D
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 Mars. Distance from Sun: same as Earth. Rotation rate: once every 18 hours. c) Size: same as Venus. Distance from Sun: same as Mars. Rotation rate: once every 25 hours. d) Size: same as the Moon. Distance from Sun: same as Mars. Rotation rate: once every 10 days.
D
The densities of planets close to the Sun a) are low because they become massive enough during formation to retain H and He. b) are low because they are small. c) are high because they are quite massive. d) are high because they formed out of high density materials with high melting points.
D
The nebular theory also predicts that the cloud should heat up as it collapses. What physical law explains why it heats up? a) Kepler's second law b) the law of conservation of angular momentum c) Newton's third law of motion d) the law of conservation of energy e) the universal law of gravitation
D
The processes responsible for virtually all surface geology 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
The reason that small planets tend to lose interior heat faster than larger planets is essentially the same as the reason that ________. a) gas bubbles form and rise upward in boiling water b) thunderstorms tend to form on hot summer days c) Earth contains more metal than the Moon d) a large baked potato takes longer to cool than a small baked potato
D
Venus has a higher average surface temperature than Mercury. Why? a) Because its surface is covered with hot lava from numerous active volcanoes. b) Because its slow rotation gives it more time to heat up in sunlight. c) Because it is closer to the Sun. d) Because its surface is heated by an extreme greenhouse effect.
D
What do we mean by a runaway greenhouse effect? a) a greenhouse effect that starts on a planet but later disappears as gases are lost to space b) a greenhouse effect that heats a planet so much that its surface rock melts c) a process that heats a planet like a greenhouse effect, but that involves a completely different mechanism of heating that doesn't actually involve greenhouse gases d) a greenhouse effect that keeps getting stronger until all of a planet's greenhouse gases are in its atmosphere
D
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) They lost interior heat to outer space. d) When their interiors were molten, denser materials sank toward their centers and lighter materials rose toward their surfaces.
D
What drives the motion of the tectonic plates on Earth? a) Earth's magnetic field b) tidal forces c) the Coriolis force d) convection cells in the mantle e) lava flows in trenches along the sea floor
D
What is the giant impact hypothesis for the origin of the Moon? a) The Moon formed just like Earth, from accretion in the solar nebula. b) 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. c) The Moon formed when two gigantic asteroids collided with one another. d) The Moon formed from material blasted out of Earth's mantle and crust by the impact of a Mars-size object.
D
What patterns can be seen comparing the terrestrial planets (Mercury, Venus, Earth, Mars) to the Jovian planets (Jupiter, Saturn, Uranus, Neptune)? a) The jovian planets are much more massive. b) The terrestrial planets are much more dense. c) The terrestrial planets are rocky and the jovian planets are gaseous. d) All of the above e) A and C.
D
Where did Earth's (interior) heat come from? a) volcanoes b) accretion c) radioactivity d) B and C e) all of the above
D
Where did hydrogen and helium gas condense in the protoplanetary nebula? a) throughout the solar system b) only inside the frost line c) only outside the frost line d) nowhere
D
Which internal energy source is the most important in continuing to heat the terrestrial planets today? a) accretion b) tidal heating c) differentiation d) radioactivity e) all of the above
D
Which of the following Mars surface features provides dramatic evidence that volcanism has played a role in shaping the surface of Mars? a) the polar caps b) the southern highlands c) Valles Marineris d) Olympus Mons
D
Which of the following does NOT provide evidence that Mars once had abundant liquid water on its surface? a) the presence of "blueberries" made of the mineral hematite b) the presence of features that look like dried-up riverbeds c) the presence of very old craters that appear to have been eroded by rain d) the presence of canali, discovered in the late 1800s by Giovanni Schiaparelli and mapped by Percival Lowell
D
Which of the following geological activity on Venus is stronger than that on Earth? a) .Erosion b) Plate tectonics c) Small impact cratering d) Volcanism
D
Which of the following is not a line of evidence supporting the hypothesis that our Moon formed as a result of a giant impact? a) Computer simulations show that the Moon could really have formed in this way. b) 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. c) The Moon has a much smaller proportion of easily vaporized materials than Earth. d) The Pacific Ocean appears to be a large crater, probably the one made by the giant impact.
D
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
Which of the following is not a major pattern of motion in the solar system? a) All of the planets orbit the Sun in the same direction; counterclockwise as viewed from above Earth's north pole. b) The Sun and most of the planets rotate in the same direction in which the planets orbit the Sun. c) Most of the solar system's large moons orbit in their planet's equatorial plane. d) Nearly all comets orbit the Sun in same direction and roughly the same plane.
D
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
D
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 thickness of the lithosphere depends on interior temperature, with cooler interiors leading to thicker lithospheres. c) The lithosphere extends from somewhere in the mantle all the way to the surface. d) The lithosphere is broken into a set of large plates that float on the softer rock below.
D
Which of the following observations indicates that conditions on Mars may have been suitable for life in the past? a) There are very large extinct volcanoes on Mars. b) Mars has polar caps made of "dry ice." c) Mars has two small moons. d) There are dried-up riverbeds on Mars. e) There is a very deep and long canyon that extends across Mars.
D
Which of these facts is NOT explained by the nebular theory? a) There are two main types of planets: terrestrial and jovian. b) Planets orbit in same direction and plane. c) Existence of asteroids and comets. d) Number of planets of each type (four terrestrial and four jovian).
D
Which planet is approximately halfway between Pluto's orbit and the Sun? a) Mars, the fourth planet from the Sun b) Jupiter, the fifth planet from the Sun c) Saturn, the sixth planet from the Sun d) Uranus, the seventh planet from the Sun
D
Which planet(s) have an atmosphere that consists mostly of carbon dioxide? a) Venus only b) Venus, Earth, and Mars c) Mars only d) Venus and Mars
D
Which planet, other than Earth, has visible water ice on it? a) the Moon b) Jupiter c) Venus d) Mars e) Mercury
D
Which planets have NO moons? a) Mercury and Mars b) Venus, Jupiter and Uranus c) Uranus and Neptune d) Venus and Mercury e) Saturn and Jupiter
D
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 had lost its water and developed a thick lithosphere. c) It rotates rapidly. d) all of the above e) B and C
D
Most of the solar system's planets a) are made of rocks and minerals. b) are made of gas. c) orbit the Sun in the same direction. d) rotate in the same direction as they orbit the Sun. e) C and D
E
Observations show that interstellar clouds can have almost any shape and, if they are rotating at all, their rotation is not perceptible. However, the nebular theory predicts that a cloud will rotate rapidly once it shrinks to a relatively small size. What physical law explains why a collapsed cloud will rotate rapidly? a) Kepler's second law b) Newton's third law of motion c) the law of conservation of energy d) the universal law of gravitation e) the law of conservation of angular momentum
E
On Aug. 5, 2017, Venus is in Gemini from Earth. If you stand on Venus, which constellation is Earth in? a) Gemini b) Big Dipper c) North pole d) Taurus e) Sagittarius
E
Rank the following in order from lowest to highest melting point: iron, hydrogen, water, rock, methane a) Water, rock, iron, methane, hydrogen b) Methane, water, iron, rock, hydrogen c) Water, methane, rock, iron, hydrogen d) Methane, water, hydrogen, iron, rock e) Hydrogen, methane, water, rock, iron
E
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) Water ice in Mar's polar caps e) all of the above
E
What is necessary for differentiation to occur in a planet? a) It must have metal and rock in it. b) It must be 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
What substances were found in the innermost regions (within about the inner 0.3 AU) of the solar system before planets began to form? a) nothing at all b) only rocks and metals c) only hydrogen compounds d) only hydrogen and helium gases e) rocks, metals, hydrogen compounds, hydrogen, and helium, all in gaseous form
E