Astro 103 Chapter 10

What is the approximate age of the oldest rocks brought back from the Moon by astronauts during the Apollo program? A. 4.3 billion years B. 10 billion years C. 3.5 billion years D. 4.3 million years

A. 4.3 billion years

Which of the following general statements about the Moon is true? A. There is one side of the Moon from which Earth can never be seen. B. The Moon does not rotate on its axis. C. There is one side of the Moon from which the Sun can never be seen. D. One side of the Moon is always in darkness.

A. There is one side of the Moon from which Earth can never be seen

The theory that seems to account most satisfactorily for the origin of the Moon at the present time is that A. a large object collided with Earth and ejected the material that formed the Moon. B. the Moon formed by accretion elsewhere in the solar system and was captured later by Earth. C. the Moon formed from material spun off from Earth when Earth was molten and spinning rapidly, early in its history. D. the Moon formed from material already in orbit around Earth.

A. a large object collided with Earth and ejected the material that formed the Moon.

What is a scarp? A. a long wall formed when the Moon's surface cooled and shrank B. the peak in the center of a large crater C. an especially high crater wall D. a deep trench stretching hundreds of kilometers across the lunar surface

A. a long wall formed when the Moon's surface cooled and shrank

How long is a "lunar day," or the time between two successive sunrises or sunsets on the Moon? A. about 1 month B. infinitely long, because the Moon does not rotate about its axis with respect to the Sun C. about 1 year D. about 1 day

A. about 1 month

What is the current state of plate tectonics on the Moon? A. absent; the Moon is a geologically dead world B. just in the process of beginning; the rilles (or sinuous valleys) are the first signs of continental rifting C. dying out; only the lunar maria show signs of tectonic movement today D. very active, causing mountain uplift around the edges of several lunar maria

A. absent; the Moon is a geologically dead world

The smooth, dark maria on the Moon are A. immense impact basins that are smooth because they were covered by lava flows after a period of heavy bombardment early in the Moon's history. B. regions that are as old as the cratered highlands but escaped a period of heavy bombardment by being on the "wrong" side of the Moon. C. immense impact basins that are smooth because earlier craters were wiped out by shock waves from the impacts. D. areas that were still molten at the time of the early, heavy bombardment.

A. immense impact basins that are smooth because they were covered by lava flows after a period of heavy bombardment early in the Moon's history.

A regolith is a(n) A. layer of pulverized rock on the surface of a planet or other object. B. extremely large, isolated rock on the surface of a planet or other object. C. heavily cratered region on a planet or other object. D. lithospheric plate, moved slowly by geologic processes

A. layer of pulverized rock on the surface of a planet or other object.

The Moon has A. no measurable atmosphere or liquid water. B. no measurable atmosphere, but plenty of groundwater. C. an atmosphere of CO2, but no evidence of water. D. a lot of evidence for an atmosphere and the presence of liquid water (E.g., wind erosion and winding river valleys

A. no measurable atmosphere or liquid water.

The type of rock making up the lunar highlands is A. old, low-density rocks—anorthosite. B. young volcanic rocks—basalt. C. deposited rocks—limestone. D. volcanic rocks transformed by subsequent heat and pressure—granite.

A. old, low-density rocks—anorthosite

What are the most common shapes of lunar craters and why? A. round, because the shock wave from the impact that produced them spread out uniformly in all directions B. random shapes, because mantle convection has deformed the surface and distorted the craters since their production by impacts of meteoroids C. all shapes from round to long and thin, depending on the angle at which the projectile hit the surface D. round, because most of the craters were produced by volcanic explosions that formed calderas, not by meteoroid impacts

A. round, because the shock wave from the impact that produced them spread out uniformly in all directions

Because of the tides on Earth's oceans, the Moon is A. spiraling outward away from Earth. B. unaffected and continues to orbit in a constant elliptical path. C. shrinking. D. moving slowly toward Earth.

A. spiraling outward away from Earth.

Detailed examination of the overall surface of the Moon and of the rocks brought back by Apollo astronauts reveals that A. unlike Earth's rocks, there is no evidence of water locked into crystal structures in lunar rocks, but there are significant quantities of ice in cold lunar polar regions. B. there have been short periods in recent history when water existed on the Moon, during which the rilles or river valleys were formed. C. no water exists in either liquid form or ice now but, like terrestrial rocks, some water is contained within the crystal structure of lunar rocks. D. water probably existed on the Moon earlier and formed lake beds or maria, but it has evaporated.

A. unlike Earth's rocks, there is no evidence of water locked into crystal structures in lunar rocks, but there are significant quantities of ice in cold lunar polar regions.

Why are the lunar maria concentrated almost entirely on the near side of the Moon? A. The apparent concentration of maria on the near side is merely an illusion caused by the fact that the near side is the only side that we can see. B. The crust is thicker on the far side of the Moon, restricting massive lava flows after asteroid impact. C. Earth's gravity has concentrated meteoroid impacts on the far side of the Moon, erasing the ancient, smooth lava plains. D. Earth's gravity concentrated asteroid impacts on the near side of the Moon.

B. The crust is thicker on the far side of the Moon, restricting massive lava flows after asteroid impact.

Is there any correlation between the color of the Moon's surface material and the elevation at which it is found? A. No, the Moon's surface material is all the same color. B. Yes, darker materials are generally found at lower elevations. C. Yes, darker materials are generally found at higher elevations. D. No, colors of surface material are mixed at all elevations.

B. Yes, darker materials are generally found at lower elevations.

The maria on the Moon appear to be A. lava flows around giant ancient volcanoes. B. craters filled with basalt from within the Moon. C. evenly distributed on the near side and the far side of the Moon. D. former ocean basins from which the water has escaped.

B. craters filled with basalt from within the Moon.

The Moon has A. a global magnetic field that deflects the solar wind, but is not strong enough to trap high-energy charged particles. B. no global magnetic field, although weak magnetism in lunar rocks does show that a magnetic field existed earlier in the Moon's history. C. no detectable magnetism of any kind, either global or in individual rocks. D. a very weak global field that is not strong enough to deflect the solar wind before it hits the lunar surface.

B. no global magnetic field, although weak magnetism in lunar rocks does show that a magnetic field existed earlier in the Moon's history.

Moonquakes A. never occur; the Moon is seismically quiet. B. occur but are much weaker and much less frequent than earthquakes. C. are much more violent and occur much more often than earthquakes. D. occur, but only from the impact of meteoroids from space.

B. occur but are much weaker and much less frequent than earthquakes.

Examination of the whole surface of the Moon shows us that A. surface features are distributed uniformly over the whole Moon. B. the Moon appears to have two distinctly different sides, that seen from Earth and that hidden from Earth. C. the northern hemisphere is distinctly different from the southern hemisphere. D. craters exist only on one side of the Moon.

B. the Moon appears to have two distinctly different sides, that seen from Earth and that hidden from Earth.

It was originally thought questionable whether a manned lunar landing could take place because A. of the extreme temperatures on the lunar surface. B. the lunar surface might be too soft to land on. C. of extreme levels of radiation from the decay of radioactive elements and the lack of a shielding atmosphere. D. the low atmospheric pressure would adversely affect human beings.

B. the lunar surface might be too soft to land on.

Suppose that two regions on the Moon have ages, respectively, of 3.7 and 4.3 billion years. Based on these ages, we expect to find that A. the older region has fewer craters than the younger region because the cratering rate was lower at earlier times. B. the older region has far more craters than the younger region because of changes in the cratering rate over that time. C. both regions have roughly the same amount of cratering because they have approximately the same age. D. the older region has 16% more craters than the younger region because its age is 16% greater than that of the younger region.

B. the older region has far more craters than the younger region because of changes in the cratering rate over that time.

What is the primary cause of moonquakes? A. meteoroid impact B. tidal forces due to the gravitational pull of Earth C. tidal forces due to the gravitational pull of the Sun D. the collision of tectonic plates

B. tidal forces due to the gravitational pull of Earth

How old are the lunar maria? A. less than 1 billion years old B. 1.8 to 2.6 billion years old C. 3.1 to 3.8 billion years old D. 4.0 to 4.3 billion years old

C. 3.1 to 3.8 billion years old

Which was the first spacecraft to land humans on the Moon? A. Apollo 13 B. Ranger 9 C. Apollo 11 D. Soyuz 5

C. Apollo 11

What kinds of large-scale changes have occurred on the Moon in the last billion years? A. volcanic activity and large scale lava flows B. None. The Moon is exactly as it was a billion years ago. C. Constant meteoroid impact has gently sculpted the landscape. D. tectonic activity

C. Constant meteoroid impact has gently sculpted the landscape.

Which of the following statements is a correct description of the rotation of Earth? A. The average length of a day varies unpredictably from one year to the next because of the combined effects of solar and lunar tides. B. The average length of a day is constant from year to year because nothing can change the speed of rotation of Earth. C. The average length of a day is gradually getting longer because Earth's rate of rotation is slowing down. D. The average length of a day is gradually getting shorter because Earth's rate of rotation is speeding up.

C. The average length of a day is gradually getting longer because Earth's rate of rotation is slowing down.

The lunar maria are composed of which of the following rock types? A. limestone B. anorthosite C. basalt D. granite

C. basalt

The terminator on the Moon is a line A. joining north and south lunar poles, passing through the center of the largest mare, Imbrium, representing 0° of lunar longitude. B. between the near and far sides of the Moon. C. between the solar-illuminated and dark hemispheres. D. along the equator, between northern and southern hemispheres.

C. between the solar-illuminated and dark hemispheres.

The age of Moon rocks has been determined primarily by what method? A. careful chemical analysis of the constituents B. measurements of radioactive decay products C. careful examination of the site and surroundings, and particularly the measurement of the crater density, from which the rocks were acquired D. counting the numbers of micrometeoroid craters on the rock surface

C. careful examination of the site and surroundings, and particularly the measurement of the crater density, from which the rocks were acquired

The near and far sides of the Moon are particularly different in that the A. number of craters differs markedly, with fewer on the far sidE. B. average height of the overall terrain is much lower on the far sidE. C. far side has no maria. D. far side is always in darkness.

C. far side has no maria.

Lunar rocks brought back by Apollo astronauts and remote-controlled Russian spacecraft are basically A. sedimentary rocks, with layered structure from repeated deposition and subsequent compression. B. mostly metamorphic rocks, changed by pressure and heat from their original volcanic lava state. C. igneous rocks, formed from cooling lava. D. a mixture of igneous, volcanic, and sedimentary rocks.

C. igneous rocks, formed from cooling lava.

Most of the craters on the Moon were created by A. volcanic activity during the early part of the Moon's history that left old calderas. B. impacts of fragments of asteroids more or less evenly and continuously over the history of the Moon. C. impacts of rocky debris during the first billion years of the Moon's history. D. debris flying out to the Moon from asteroid impacts on Earth.

C. impacts of rocky debris during the first billion years of the Moon's history.

Compared to earthquakes, moonquakes are A. much more frequent but significantly weaker, occurring at any time. B. much less frequent but significantly stronger, occurring mostly at full moon. C. much weaker and less frequent, occurring mostly when the Moon is at perigee. D. nonexistent, the Moon being seismically quiet.

C. much weaker and less frequent, occurring mostly when the Moon is at perigee.

To observers on Earth, the Moon shows A. only its northern half because of the tilt of the Moon's rotational axis. B. its whole surface once per month as it rotates. C. only one side to Earth at all times. D. its whole surface once per year as Earth moves around the Sun.

C. only one side to Earth at all times

The mountain ranges on the Moon are A. lines of extinct volcanoes similar to the Hawaiian Islands, caused by hot-spot vulcanism. B. the hard-rock remnants of geological features severely eroded by wind and weather. C. the walls of craters caused by impacts of large objects early in the geological history of the Moon. D. the upthrust caused by collisions of moving tectonic plates.

C. the walls of craters caused by impacts of large objects early in the geological history of the Moon.

How old are the lunar highlands? A. 3.1 to 3.8 billion years old B. 1.8 to 2.6 billion years old C. less than 1 billion years old D. 4.0 to 4.3 billion years old

D. 4.0 to 4.3 billion years old

Astronauts at a Moon base visible from Earth will not see A. only one side of Earth, because the Moon revolves at the same rate as Earth rotates. B. sunrise or sunset, because the Sun will always remain in their sky. C. the stars moving through their sky, because the Moon does not rotate. D. Earthrise or Earthset.

D. Earthrise or Earthset.

If viewed from a point directly above the plane of the planetary system, how would the Moon appear to rotate on its axis? A. It would rotate once per year as Earth and Moon orbit the Sun together. B. It would not rotate at all, because we always see the same face on Earth. C. It would rotate once per day, to maintain its direction toward Earth. D. It would rotate once per month, or once per revolution about Earth.

D. It would rotate once per month, or once per revolution about Earth.

The impact craters on Earth are younger than a few million years old, whereas ages of lunar craters extend back billions of years. Why is this? A. Earth's surface has been covered by lava flows several times in its history, whereas such activity ceased on the Moon several million years ago. B. Earth escaped the heavy bombardment that pelted the Moon early in its history. C. Weathering by rain and melting snow gradually erases craters on Earth, and this does not happen on the Moon. D. Plate tectonics has erased older craters on Earth, whereas this process has not occurred on the Moon.

D. Plate tectonics has erased older craters on Earth, whereas this process has not occurred on the Moon.

The Moon raises tides on Earth. Does Earth raise tides on the Moon? A. No. Earth exerts differential tidal forces on the Moon, but the Moon is much more rigid than Earth (which is why there are no plate tectonics on the Moon) so these forces have no effect. B. No. The Moon has no oceans (or liquid water of any kind. so there are no tides. C. Yes, but these affect only the deep core of the Moon (the only liquid part of the Moon). The surface remains unaffected. D. Yes, small tidal bulges are raised on the Moon's surface as Earth's gravity distorts the Moon's shape (and causes moonquakes).

D. Yes, small tidal bulges are raised on the Moon's surface as Earth's gravity distorts the Moon's shape (and causes moonquakes).

What appears to be the "impact history" of cratering on the Moon? A. short periods of heavy bombardment alternating with long periods of light bombardment throughout the Moon's life B. heaviest bombardment when the Moon first formed, gradually decreasing (except for increased activity about four billion years ago) to light bombardment today C. more or less constant bombardment from the earliest times to the present D. an early period of heavy bombardment followed by a decrease in intensity (except for a spike around four billion years ago) and then very light bombardment to the present

D. an early period of heavy bombardment followed by a decrease in intensity (except for a spike around four billion years ago) and then very light bombardment to the present

The lunar maria appear smooth because they are A. ancient sea beds, now dry, dating back to when the Moon had a denser atmosphere and rainfall was abundant. B. recent lava flows, occurring within the last billion years, which have obliterated earlier craters. C. regions where craters have been obliterated by crustal deformation caused by hot spots and volcanic lava flow from the underlying molten mantle. D. ancient lava flows that occurred soon after the end of an early period of intense bombardment and have had relatively few impacts since then.

D. ancient lava flows that occurred soon after the end of an early period of intense bombardment and have had relatively few impacts since then

What is the origin of the majority of lunar craters? A. impacts by space probes B. surface collapse after loss of groundwater by evaporation C. volcanic explosions D. impacts by meteoric material

D. impacts by meteoric material

Which of the following kinds of rocks are not found on the Moon? A. anorthosite B. breccias C. basalt D. limestone

D. limestone

Compared to rocks on Earth, lunar rocks are A. identical in composition, except for having no water of crystallization B. composed of the same elements but in very different proportions. C. slightly enriched in elements that melt at low temperatures, depleted in elements that melt at high temperatures. D. slightly depleted in elements that melt at low temperatures, enriched in elements that melt at high temperatures, and contain no water of crystallization.

D. slightly depleted in elements that melt at low temperatures, enriched in elements that melt at high temperatures, and contain no water of crystallization.

One effect of the tidal drag of the ocean waters on Earth is to A. speed up its rate of spin, thereby gaining energy from the Moon's orbital motion. B. speed up Earth in its orbital motion around the Sun. C. tilt its spin axis farther and farther away from the perpendicular to the ecliptic. D. slow down Earth's spin rate.

D. slow down Earth's spin rate.

Can regions of ice exist on the surface of the Moon? A. no, because the Moon never had water from which ice could form B. no, because all parts of the Moon are heated by the Sun at one time or another during each orbit, and all ice would evaporate C. no, because the Moon has no atmosphere, and ice would quickly evaporate (or "sublime") into space and be lost D. yes, because the floors of craters at the north and south poles can be permanently shaded from the Sun

D. yes, because the floors of craters at the north and south poles can be permanently shaded from the Sun