Question 1

The density of Mercury is about the same as that of Earth, but Mercury contains a larger proportion of iron. How is this possible?

Accepted Answer

A)   The iron in Mercury's core is accompanied by a very low-density crust. The average density is thus comparable to the density of Earth.
B)   The inner core of Mercury is hollow, thus reducing the overall density much below that of iron.
C)   Mercury has only 1/18 Earth's mass. Thus, it must be composed of heavier materials (like iron)  in order to match Earth's density.
D)   Earth contains, proportionally, a smaller volume of iron, but because of Earth's greater mass, Earth's iron has been compressed to a higher density than the iron on Mercury.E) A) and D)
F) A) and C)

Question 2

Mercury's atmosphere is

Accepted Answer

A)   almost nonexistent.
B)   relatively dense, composed mostly of nitrogen (80 percent)  and oxygen (20 percent) .
C)   very thin, made up of sulfur dioxide and hydrogen sulfide from volcanoes.
D)   relatively thin, composed of carbon dioxide with small quantities of nitrogen and argon.E) A) and C)
F) None of the above

Question 3

Craters on Mars have flatter bottoms and their rims appear to be more worn down than those on either Earth's Moon or Mercury. What has caused this wear?

Accepted Answer

A)   breakdown of the rocks by the extreme temperature variations between day and night
B)   erosion by the seasonal fall and subsequent melting of carbon dioxide snow
C)   erosion by wind and infilling by dust storms
D)   erosion by rainfall, now and in the pastE) A) and B)
F) C) and D)

Question 4

In what way was the production of the major volcanoes on Mars different from the production of the Hawaiian Islands on Earth?

Accepted Answer

A)   The Martian volcanoes formed while Mars was still completely molten, whereas the Hawaiian Islands formed recently, after Earth's crust had solidified.
B)   The Martian volcanoes formed in crust that was stationary over an underlying hot spot, whereas the Hawaiian Islands formed in crust that was moving over an underlying hot spot.
C)   The Martian volcanoes formed through crustal shattering by a major impact, whereas the Hawaiian Islands formed by volcanic action over an underlying hot spot in Earth's upper mantle.
D)   The Martian volcanoes formed in crust that was moving over an underlying hot spot, whereas the Hawaiian Islands formed along a boundary between two crustal plates.E) B) and C)
F) B) and D)

Question 5

What role has methane played in the search for life on Mars?

Accepted Answer

A)   Methane destroys simple life-forms, so the existence of methane precludes the existence of simple life-forms on Mars.
B)   Methane is produced by life-forms, so the search for methane being released from under the Martian surface-so far unsuccessful-continues.
C)   Sunlight breaks down methane within a few centuries. The presence of methane on Mars suggests that it is being renewed continually, perhaps by living organisms.
D)   So far methane has played no role in the search for life on Mars.E) A) and B)
F) A) and C)

Question 6

Evidence of past water on Mars comes from each of these EXCEPT

Accepted Answer

A)   polygon-shaped cracks in rocks.
B)   dried-up lakebeds and riverbeds.
C)   the presence of small, round hematite rocks.
D)   observation of water-rich bodies striking the planet, implying more of them did so in the past.E) All of the above
F) None of the above

Question 7

The origin of the Martian magnetic field appears to be

Accepted Answer

A)   magnetic material deposited by impacts of iron meteorites.
B)   an electric dynamo still operating in the small Martian core.
C)   convection of molten, iron-rich lava in the Martian mantle.
D)   remnant magnetism from an earlier global magnetic field when Mars was young.E) B) and C)
F) C) and D)

Question 8

At greatest elongation, the Earth-Venus line makes an angle with the Sun-Venus line that is

Accepted Answer

A)   nearly 180°.
B)   90°.
C)   0°.
D)   an acute angle, less than 90°.E) A) and C)
F) C) and D)

Question 9

Seasons on Mars last nearly twice as long as those on Earth because

Accepted Answer

A)   Mars's tilt on its axis is nearly twice the angle of Earth's tilt.
B)   Mars takes nearly twice as long to rotate on its axis as Earth does.
C)   Mars takes nearly twice as long to orbit the Sun as Earth does.
D)   Mars is nearly twice as far from the Sun as Earth is.E) B) and D)
F) B) and C)

Question 10

The albedo, or fraction of light reflected from the surface, of Mercury is

Accepted Answer

A)   fairly high, about the same as that of Earth.
B)   very low because of its dark rocky surface and absence of an atmosphere.
C)   variable and relatively high because of variable cloud cover.
D)   very high because of the light color of its surface.E) A) and B)
F) A) and D)

Question 11

What is the observed feature that suggests that Mercury's iron core is at least partly molten?

Accepted Answer

A)   presence of a global magnetic field
B)   background sloshing sound in radio transmissions sent back by the Mariner 10 spacecraft
C)   irregularities in Mercury's rotation rate
D)   extensive lava flows near the regions of greatest tidal stress, such as the Caloris BasinE) A) and D)
F) A) and B)

Question 12

Two observed features on Mars appear to lead to contrary geological conclusions-the appearance of massive, solitary volcanoes, apparently caused by hot spots under the planet's surface, and the discovery of a long, deep rift valley across the planet. Why are the two features a contradiction?

Accepted Answer

A)   Volcanoes suggest a molten inner planet, whereas a rift valley suggests the presence of a solid core.
B)   Massive volcanoes should have covered the planet's surface, including the valley, with dust and ash, but the valley remains as a major feature.
C)   Ancient volcanoes show no sign of erosion by water, whereas the valley suggests prolonged rainfall and erosion.
D)   Single massive volcanoes indicate hot-spot volcanism with no plate tectonic motion, whereas a rift valley suggests otherwise.E) A) and B)
F) None of the above

Question 13

Spacecraft measurements indicate that the surface of Venus is dominated by

Accepted Answer

A)   sandstone, a sedimentary rock formed on Venus by sand grains deposited by wind.
B)   granite, a plutonic rock formed when lava solidifies deep below the surface.
C)   basalt, a volcanic rock formed when lava solidifies on the surface.
D)   schist, a metamorphic rock formed by the deformation of other rocks by pressure and heat.E) B) and D)
F) B) and C)

Question 14

The approximate pressures of the atmospheres at the surfaces of Mercury, Venus, and Mars, in terms of the pressure at the surface of Earth (known as 1 atmosphere) , are, respectively,

Accepted Answer

A)   0; about 10 atmospheres; 1/10 atmosphere.
B)   1/100 atmosphere; almost 100 atmospheres; 1/10 atmosphere.
C)   1/10 atmosphere; almost 100 atmospheres; 1/10 atmosphere.
D)   0; almost 100 atmospheres; 1/100 atmosphere.E) A) and B)
F) B) and C) D

Question 15

Earth's average density (5520 kg/m3)  is slightly higher than that of Mercury (5430 kg/m3)  because

Accepted Answer

A)   Earth has a larger iron core in proportion to its size than Mercury has.
B)   Earth is more massive than Mercury and has therefore become more compressed, gravitationally.
C)   Mercury's interior has expanded slightly because of radioactive heating, reducing its density since its formation.
D)   Earth has a denser atmosphere than Mercury has.E) B) and D)
F) A) and D)

Question 16

Which of these does NOT describe an argument in favor of the presence of active volcanoes on Venus at the present time?

Accepted Answer

A)   There has been confirmed observation of lightning in Venus's atmosphere.
B)   There has been confirmed observation of hot spots in rift valleys on Venus's surface.
C)   There has been confirmed observation of natural radioactivity on Venus's surface.
D)   There has been confirmed observation of short-lived sulfur compounds in Venus's atmosphere.E) None of the above
F) A) and B) C

Question 17

The "snow" that occasionally falls in and near the polar regions of Mars consists of

Accepted Answer

A)   water ice.
B)   frozen sulfuric acid droplets.
C)   very fine white dust, disturbed occasionally by fierce wind storms.
D)   carbon dioxide ice.E) B) and D)
F) None of the above D

Question 18

How was water ice discovered near Mercury's poles?

Accepted Answer

A)   by studying reflections of radio waves sent to Mercury from Earth
B)   visually by cameras aboard Mariner 10
C)   by a surface rover sent out by MESSENGER
D)   visually from the Hubble Space TelescopeE) A) and B)
F) A) and C)

Question 19

In what way was the production of the major volcanoes on Mars similar to the production of the Hawaiian Islands on Earth?

Accepted Answer

A)   The major volcanoes on Mars and the Hawaiian Islands were both produced by the collision of an oceanic plate with a continental plate.
B)   The major volcanoes on Mars and the Hawaiian Islands were both produced by hot-spot volcanism resulting from the upflow of heat from below.
C)   The major volcanoes on Mars and the Hawaiian Islands were both produced by upwelling magma along a boundary where two plates are separating.
D)   The major volcanoes on Mars and the Hawaiian Islands were both produced by shattering of the crust by a major impact and the consequent release of subsurface magma.E) A) and D)
F) None of the above

Question 20

The surface features and overall topology of Venus have been determined primarily by

Accepted Answer

A)   balloon-borne spacecraft, launched into the Venusian atmosphere by spacecraft.
B)   surface lander vehicles that have explored the surface thoroughly.
C)   visible and UV photography from the space shuttle.
D)   radar methods from Venus-orbiting spacecraft, measuring radio echoes from the surface.E) B) and C)
F) A) and D)

Exam 8: The Other Terrestrial Planets

The density of Mercury is about the same as that of Earth, but Mercury contains a larger proportion of iron. How is this possible?

Correct AnswerverifiedShow Answer

Mercury's atmosphere is

Correct AnswerverifiedShow Answer

Craters on Mars have flatter bottoms and their rims appear to be more worn down than those on either Earth's Moon or Mercury. What has caused this wear?

Correct AnswerverifiedShow Answer

In what way was the production of the major volcanoes on Mars different from the production of the Hawaiian Islands on Earth?

Correct AnswerverifiedShow Answer

What role has methane played in the search for life on Mars?

Correct AnswerverifiedShow Answer

Evidence of past water on Mars comes from each of these EXCEPT

Correct AnswerverifiedShow Answer

The origin of the Martian magnetic field appears to be

Correct AnswerverifiedShow Answer

At greatest elongation, the Earth-Venus line makes an angle with the Sun-Venus line that is

Correct AnswerverifiedShow Answer

Seasons on Mars last nearly twice as long as those on Earth because

Correct AnswerverifiedShow Answer

The albedo, or fraction of light reflected from the surface, of Mercury is

Correct AnswerverifiedShow Answer

What is the observed feature that suggests that Mercury's iron core is at least partly molten?

Correct AnswerverifiedShow Answer

Two observed features on Mars appear to lead to contrary geological conclusions-the appearance of massive, solitary volcanoes, apparently caused by hot spots under the planet's surface, and the discovery of a long, deep rift valley across the planet. Why are the two features a contradiction?

Correct AnswerverifiedShow Answer

Spacecraft measurements indicate that the surface of Venus is dominated by

Correct AnswerverifiedShow Answer

The approximate pressures of the atmospheres at the surfaces of Mercury, Venus, and Mars, in terms of the pressure at the surface of Earth (known as 1 atmosphere) , are, respectively,

Correct AnswerverifiedD

Earth's average density (5520 kg/m3) is slightly higher than that of Mercury (5430 kg/m3) because

Correct AnswerverifiedShow Answer

Which of these does NOT describe an argument in favor of the presence of active volcanoes on Venus at the present time?

Correct AnswerverifiedC

The "snow" that occasionally falls in and near the polar regions of Mars consists of

Correct AnswerverifiedD

How was water ice discovered near Mercury's poles?

Correct AnswerverifiedShow Answer

In what way was the production of the major volcanoes on Mars similar to the production of the Hawaiian Islands on Earth?

Correct AnswerverifiedShow Answer

The surface features and overall topology of Venus have been determined primarily by

Correct AnswerverifiedShow Answer

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D

Earth's average density (5520 kg/m³) is slightly higher than that of Mercury (5430 kg/m³) because

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C

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D

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