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The best way to find the exact distance to the Moon is to:
A) measure its exact size in the telescope.
B) use radar reflection times, about 2.56 second.
C) bounce lasers off the retroreflectors left on the surface by the Apollo landings.
D) make parallax measurements from observatories on opposite sides of the Earth.
E) use stellar occultations for precise timings of the Moon’s position.
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Answer: C
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What is the reason that it is so difficult to view Mercury from Earth?
A) Mercury is very dim.
B) Mercury is very small.
C) Mercury can’t be seen at night.
D) Mercury is often hidden by the Moon.
E) Mercury is always very close to the Sun.
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Answer: E
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Mercury is very hard to observe from Earth because:
A) it always appears as only half lit from Earth.
B) it never gets more than 28 degrees from the Sun’s glare.
C) its elliptical orbit causes it to change speed unpredictably.
D) its barren surface reflects too little sunlight; it is almost invisible always.
E) its very rugged surface does not allow radar to bounce back to Earth.
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Answer: B
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From Earth, due to their motions and the fact that the Sun lights only a portion of each surface, both Mercury and the Moon:
A) always look full from Earth.
B) appear to go through phases.
C) pass through Earth’s shadow.
D) appear to be half-lit by the Sun.
E) always have the same side facing Earth.
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Answer: B
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Mercury experiences extreme high and low temperatures between night and day because:
A) it is so close to the Sun.
B) its dense atmosphere creates a runaway greenhouse.
C) its oceans are much hotter than ours.
D) Mercury has no axial tilt, with its equator always exposed to direct sunlight.
E) it has no true atmosphere to moderate temperatures over the globe.
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Answer: E
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In size, Mercury is intermediate between:
A) Earth and Venus.
B) Mars and Earth.
C) the Moon and Mars.
D) Pluto and the Moon.
E) Ceres and Pluto.
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Answer: C
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How do the atmospheres of the Moon and Mercury compare?
A) Mercury’s is much denser, like Venus, with much carbon dioxide.
B) They are about equal, each only 1% as dense as ours.
C) The cooler Moon retains a thicker nitrogen atmosphere.
D) As no spacecraft has yet landed there, no information exists about Mercury’s.
E) Neither body has a permanent true atmosphere.
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Answer: E
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If the Earth’s surface temperature were increased to that of Mercury’s day side, then:
A) we would lose most of our water vapor into space.
B) the evaporating oceans would thicken the atmosphere greatly.
C) the erupting volcanoes would greatly increase the carbon dioxide greenhouse.
D) little would happen, as the Earth is still the same mass and surface gravity.
E) the Earth would, like Mercury, lose all its atmospheric gases.
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Answer: A
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Which of the following is NOT a factor in determining whether a body in the solar system retains an atmosphere?
A) composition and weight of the gases
B) escape velocity
C) axial tilt
D) rotation rate
E) distance from the Sun
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Answer: D
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Comparing the densities of the Moon and Mercury, we find:
A) the Moon is slightly denser than Mercury.
B) similar in surface appearance, they are also similar in density.
C) that density increases as we go outward from the Sun.
D) the Moon’s is similar to Earth’s crust, while Mercury’s is similar to the entire Earth.
E) both are much denser than our water-covered planet.
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Answer: D
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One of the effects of Mercury’s very slow spin is:
A) extreme variations in its surface temperature.
B) an intensely powerful magnetic field.
C) tectonic activity.
D) wind patterns that are slow, but global in size.
E) large variations in the size of its polar cap.
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Answer: A
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Mercury’s tenuous atmosphere of sodium, magnesium, and potassium comes from:
A) atoms that have been kicked off the surface by the solar wind.
B) volcanic outgassing.
C) residual gases from Mercury’s formation.
D) impacts of asteroids or comets.
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Answer: A
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The lunar mare are found:
A) anywhere large meteor impacts created deep basins.
B) almost entirely on the far side, which was more likely to be hit.
C) almost entirely on Earth side, where the crust was thinner.
D) mainly in the south polar region, where the largest impact occurred.
E) not at all, since no liquid water really exists on the Moon.
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Answer: C
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The lunar highlands are:
A) more rugged, heavily cratered, and older than the lunar mare.
B) made of lighter colored, younger rocks than the mare.
C) formed by plate tectonics, like the Earth’s Himalayas.
D) formed by volcanic eruptions, much like our Andes.
E) brighter than the mare, since they are covered with reflective glass from the rays.
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Answer: A
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The youngest features visible with telescopes on the Moon are:
A) the volcanoes seen erupting in the highlands.
B) the craters sitting atop the mare.
C) the darkest regions of the mare.
D) the bright polar caps of new ice.
E) the scarps recently created by tectonic activity.
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Answer: B
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What is true of the lunar highlands?
A) They are found on the Moon’s northern hemisphere.
B) They are less heavily cratered than the mare.
C) They are the darker regions of the Moon seen with the naked eye.
D) They are younger than the darker mare.
E) They are the oldest part of the lunar surface.
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Answer: E
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The lunar mare are radioactively dated at:
A) 4.6 billion years old, forming first among the lunar features.
B) 4.2-3.9 billion years old, comparable to the adjacent highlands.
C) 3.9-3.2 billion years old, forming after most of the bombardment was over.
D) 3.5-2.5 billion years old, similar to the formation of our own oceans.
E) less than a billion years old, the most recent additions to the Moon.
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Answer: C
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Mercury’s smooth plains are most similar to the Moon’s:
A) maria.
B) highlands.
C) craters.
D) mountain ranges.
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Answer: A
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The oldest known features of Mercury’s surface formed:
A) about 4.6 billion years ago.
B) about 3.9-3.2 billion years ago.
C) just under 4 billion years ago.
D) less than a billion years ago.
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Answer: C
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To measure how Mercury spins, astronomers sent ________ to Mercury and used the Doppler shift to determine how fast it was rotating.
A) probes
B) laser beams
C) radar beams
D) a satellite
E) a single frequency radio signal
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Answer: C
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What did radar astronomers find in the polar regions of Mercury?
A) rift valleys
B) large mare basins, such as near our Moon’s south pole
C) water ice that never melts in the deep craters
D) polar caps of dry ice that vary seasonally, much like Mars
E) auroral displays much like Earth’s
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Answer: C
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Which statement about the rotations of the Moon and Mercury is FALSE?
A) Our Moon is in a 1:1 synch with the Earth, keeping the same side toward us.
B) Mercury is in the 3:2 synch with the Sun, with the same side Sunward at perihelion.
C) Like our Moon, Mercury does not rotate at all, keeping the same side facing the Sun.
D) On Mercury, three days exactly equal two years.
E) On the Moon, each "day" lasts about 15 Earth days of constant sunlight.
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Answer: C
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How does Mercury’s rotation relate to the Sun?
A) It always keeps one face tidally locked toward the Sun, as our Moon does with us.
B) Its year is much shorter, only 88 days, than its slow rotation of 243 days on its axis.
C) Its rotation rate is 2/3 as long as its year, due to tidal resonances.
D) Its day is the same length as its year.
E) It does not spin at all, being tidal stopped by the solar tides.
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Answer: C
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What causes Mercury’s 3:2 spin-orbit resonance?
A) the planet’s closeness to the Sun
B) the planet’s very eccentric orbit
C) the planet’s high density
D) tidal torques operating on the planet
E) All of the above are factors.
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Answer: E
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Mercury presents the same side to the Sun:
A) every other orbit.
B) all the time, just like our Moon.
C) every 12 hours.
D) every third orbit.
E) twice every orbit.
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Answer: A
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What is true of the Moon’s orbital and rotational periods?
A) The rotational period is longer.
B) The orbital period is longer.
C) The rotational period varies with the Moon’s phase.
D) They are equal.
E) The orbital period is greatest at full moon.
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Answer: D
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The chief erosive agent now on the Moon is:
A) lunar ice melting and refreezing in the polar regions.
B) lava flows welling up in the mare.
C) volcanic vents in the rugged highlands.
D) the rain of micrometeorites chewing up the regolith.
E) rain from cometary debris melting as it enters the Moon’s atmosphere.
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Answer: D
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The rate of cratering:
A) has remained constant over the last 4.6 billion years.
B) has recently increased with more collisions in the asteroid belt.
C) fluctuates over time, with massive bodies occasionally coming in from the Oort Cloud.
D) shows that large asteroid impacts are more common now than in the past.
E) shows that most interplanetary debris was swept up soon after the formation of the solar system.
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Answer: E
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The rate of cratering in the lunar highlands shows us that:
A) they must be younger than the older, darker mare.
B) they range from 4.6-4.4 billion years old, on average.
C) the largest impacts are the youngest, such as Copernicus and Tycho.
D) the oldest rocks are at least as old as the mare, but some craters are much younger.
E) most of the asteroids must have hit the Moon, not the Earth.
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Answer: B
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The average rate of erosion on the Moon is far less than on Earth because:
A) the crust of the Moon is much denser than the Earth’s crust.
B) the Moon is much younger than the Earth.
C) the Moon lacks wind, water and an atmosphere.
D) the Moon’s magnetic field protects it from the solar wind better than ours does.
E) the Moon’s mare long ago dried up, so there is no more wave erosion there.
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Answer: C
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Which type of feature is the best evidence of lunar volcanism?
A) rays around the latest eruptions
B) craters all over the Moon
C) vents seen erupting in the mountainous highlands
D) rilles associated with lava flows accompanying the mare formation
E) the Orientale Basin
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Answer: D
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What is the likely source of lunar ice?
A) water that was present when the Moon formed
B) contamination from human exploration of the Moon
C) volcanism earlier in the Moon’s history
D) impacts of meteoroids and comets
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Answer: D
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The spacecraft which reveal the possibility of lunar ice are:
A) Lunar Ranger and Surveyor.
B) Apollos XI and XVII.
C) Lunar Orbiter and Rover.
D) Clementine and Lunar Prospector.
E) Vikings 1 and 2.
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Answer: D
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Mercury’s surface most resembles that of which other body?
A) Earth
B) Moon
C) Venus
D) Mars
E) Io
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Answer: B
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Which of these features is attributed to the shrinking of Mercury’s core?
A) rilles
B) scarps
C) craters
D) mare
E) rays
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Answer: B
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The hollows on Mercury are:
A) isolated depressions found in all parts of impact craters.
B) clusters of depressions found near the center of impact craters.
C) large depressions found in the Caloris Basin.
D) large depressions found in the smooth plains.
E) clusters of depressions that are not associated with impact craters in the smooth plains.
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Answer: B
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Almost all we know about Mercury has come from:
A) telescopic observations for Earth near greatest elongations.
B) radar imaging of its rugged surface.
C) the three flybys of Mariner 10.
D) the messenger orbiter.
E) the Hubble Space Telescope’s high resolution images.
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Answer: C
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Mercury and the Moon appear similar, but we note that:
A) the lunar mare are darker than Mercury’s intercrater plains.
B) Mercury has "weird terrain" opposite its huge Caloris Basin.
C) Mercury has striking lobate scarps due to the shrinking of its core.
D) Mercury does not always keep the same face toward the Sun, while the Moon does have the Earthside always facing us.
E) All of the above are correct.
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Answer: E
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The scarps on Mercury were probably caused by:
A) tectonic activity.
B) meteorite bombardment.
C) a tidal bulge.
D) volcanism.
E) the interior cooling and shrinking.
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Answer: E
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Mercury’s surface most resembles which of these?
A) the Earth’s deserts
B) the lunar far side
C) the lunar mare
D) Venus’ polar regions
E) Mars’ deserts
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Answer: B
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Mercury’s Caloris Basin is aptly named, since:
A) it is the region on Mercury looking much like our own "painted desert."
B) it is the only such large basin on Mercury.
C) it is the hottest region, turning to face the Sun when Mercury is at perihelion.
D) it is always pointed directly at the Sun.
E) it is the largest impact basin found in the solar system.
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Answer: C
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The Moon’s huge Mare Orientale basin has a twin on Mercury named:
A) Galileo.
B) Caloris.
C) Mare Marineris.
D) the weird terrain.
E) Valhalla.
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Answer: B
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Moonquakes on the Moon were detected by:
A) the radar observations over time from Earth.
B) the seismographs left these by the Apollo astronauts.
C) laser beams reflected off mirrors left on the Moon by Apollo missions.
D) seismographs attached to the Russian Lunar rovers.
E) telescopic observations of lunar landslides.
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Answer: B
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What do moonquakes reveal about the Moon?
A) It has a strong magnetic field generated by a large molten core.
B) It has a differentiated core, displaced away from us by the Moon’s rotation.
C) Its small, partially molten core has been pulled toward us by tidal forces.
D) The Moon has been geologically dead throughout its entire history.
E) The Moon is quite active, almost as much so as Jupiter’s moon Io.
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Answer: C
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How does Mercury’s magnetic field compare to our own?
A) Like Venus, Mercury has no detectable magnetic field.
B) Like Mars and the Earth, it too has undergone polarity reversals.
C) It is 1/100th as strong as ours, but does deflect the solar wind to some degree.
D) It is amazingly strong, comparable to our own.
E) It was predicted from Mercury’s rapid rotation and molten core.
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Answer: C
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What two properties of Mercury imply that it is differentiated?
A) its size and magnetic field
B) its large average density and its surface features
C) its surface features and its size
D) its large average density and its magnetic field
E) its magnetic field and its surface features
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Answer: D
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The presence of a Mercurian magnetic field surprised the planetary scientists on the Mariner 10 team because:
A) Mercury is low in iron.
B) Mercury spins to rapidly to produce a stable dynamo.
C) It’s still too hot for its core to have differentiated.
D) The dynamo theory predicted that Mercury was spinning too slowly for one.
E) Mercury lacks an iron core.
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Answer: D
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The cores of the Moon and Mercury are similar in that
A) both cores are more iron rich than the rest of the body and the core is solid throughout.
B) both cores are large in proportion to the object with a solid inner core and fluid outer core.
C) both cores are more iron rich than the rest of the body, with a solid inner core and fluid outer core.
D) both cores are small in proportion to the object, with a fluid inner core and solid outer core.
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Answer: C
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Mercury’s magnetic field is thought to be due to:
A) dynamo action, like the Earth’s magnetic field.
B) a mechanism entirely unique to Mercury.
C) being close to the Sun.
D) being a fossil remnant dating back to the distant past when the core was more liquid.
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Answer: A
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Which of these theories seems to best explain the Moon’s origin?
A) Impact Theory
B) Capture Theory
C) Coformation Theory
D) Fission Theory
E) Fusion Theory
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Answer: A
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What are the major factors that rule out the co-formation theory for the Moon-Earth system?
A) Each body has different atmospheric content and a different density.
B) Each body has different surface features and different atmospheric content.
C) Each body has different chemical composition and different surface features.
D) Each body has a different density and a different chemical composition.
E) Each body has a different chemical composition and different atmospheric content.
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Answer: D
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Which of these would support the capture theory of the Moon’s origin?
A) the Caloris Basin on Mercury
B) the retrograde orbit and large orbital inclination of Neptune’s moon Triton
C) the rings of all the jovians lying around their equators
D) the Pluto-Charon system
E) the four large moons of Jupiter orbit its equator
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Answer: B
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The cratering of the lunar highlands shows us:
A) they are younger than the maria.
B) they are older than the smoother maria.
C) they have been unchanged for the last 4.6 billion years.
D) they are like the Earth’s continents, removed from the tectonic cycle of the mare.
E) they were made of more rigid lavas than the basalts that made the maria.
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Answer: B
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How are the polar regions of Mercury and the Moon similar?
A) Both are covered by huge mare-type basins from impacts.
B) Both seem to have ice pockets in the deepest, darkest crater floors.
C) Both have bright dry ice polar caps, like Mars.
D) Both have lakes of liquid water under their regolith.
E) Both have been hit by large comets that melted there.
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Answer: B
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Mercury’s evolution was different from the Moon’s because:
A) Mercury developed a dense atmosphere while the Moon never did.
B) Mercury was located farther from Earth, so experienced no tidal forces.
C) Mercury was subject to more intense asteroid bombardment than the Moon.
D) dense Mercury had an iron core that shrank, creating the lobate scarps.
E) Mercury developed a strong magnetic field to protect it from solar radiation.
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Answer: D
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The composition of Mercury’s crust is:
A) deficient in volatile compounds that contain elements such as sulfur and potassium.
B) consistent with material from the solar wind, indicating that Mercury has collected material over the last few billion years.
C) similar to the crust of the other terrestrial planets.
D) nearly identical to Mercury’s mantle material.
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Answer: C
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Astronomers believe that the Moon did not differentiate to the same degree as Earth because:
A) the Moon was made of solid debris, not liquids like our hydrosphere.
B) the meteors that hit the Moon were lighter than those that hit us, so did not generate as much heat on the surface.
C) the less dense and smaller Moon did not have as much radioactivity as the larger Earth in its core.
D) the Moon was formed after the Earth was, so its radioactivity was less.
E) the Moon was made of very different materials than our mantle and crust.
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Answer: C
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