Astronomy A Beginners Guide to the Universe 7th edition by Chaisson – Test Bank

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Astronomy A Beginners Guide to the Universe 7th edition by Chaisson – Test Bank

Astronomy: A Beginner’s Guide to the Universe, 7e (Chaisson/McMillan)

Chapter 6   The Terrestrial Planets: A Study in Contrasts

 

1) Venus’ rotation period is longer than its period of revolution around the Sun.

Answer:  TRUE

Diff: 1

Section Ref.:  6.1

 

2) Mercury, Venus, and Earth have similar densities.

Answer:  TRUE

Diff: 2

Section Ref.:  6.1

 

3) The density of Mars is very similar to that of the other terrestrial planets.

Answer:  FALSE

Diff: 2

Section Ref.:  6.1

 

4) Venus can appear as a crescent through the telescope.

Answer:  TRUE

Diff: 1

Section Ref.:  6.2

 

5) Mercury’s rotation and revolution are an example of a 3:2 resonance.

Answer:  TRUE

Diff: 2

Section Ref.:  6.2

 

6) Although it has no liquid water, Mercury has a tidal bulge.

Answer:  TRUE

Diff: 2

Section Ref.:  6.2

 

7) Compared to Earth, Venus spins very rapidly on its axis.

Answer:  FALSE

Diff: 1

Section Ref.:  6.2, 6.1

 

8) Atmospheric pressure on Mars is roughly half that of Earth’s at sea level.

Answer:  FALSE

Diff: 2

Section Ref.:  6.1

 

9) Venus’ surface temperature cools off at night, much like Mercury’s does.

Answer:  FALSE

Diff: 2

Section Ref.:  6.3

10) Mercury has the widest variation in surface temperatures between night and day of any planet in the solar system.

Answer:  TRUE

Diff: 1

Section Ref.:  6.3

 

11) The scarps on Mercury are extremely similar to the cratered lunar highlands in appearance.

Answer:  FALSE

Diff: 2

Section Ref.:  6.4

 

12) We now know of polar caps on Mercury, the Moon, Earth, and Mars.

Answer:  TRUE

Diff: 2

Section Ref.:  6.4

 

13) The surface temperature of Venus is 730K, even hotter than Mercury.

Answer:  TRUE

Diff: 2

Section Ref.:  6.1

 

14) No evidence of impact craters has been found on Venus.

Answer:  FALSE

Diff: 2

Section Ref.:  6.5

 

15) The surface of Mars is surprisingly smooth and featureless.

Answer:  FALSE

Diff: 1

Section Ref.:  6.6

 

16) Mars has larger volcanoes than Earth’s Hawaii.

Answer:  TRUE

Diff: 1

Section Ref.:  6.6

 

17) The polar caps and dust storms of Mars can be seen with Earth-based telescopes.

Answer:  TRUE

Diff: 2

Section Ref.:  6.6

 

18) The Moon’s far side is more ancient and heavily cratered; on Mars, the same is true of its southern hemisphere.

Answer:  TRUE

Diff: 2

Section Ref.:  6.6

 

19) Mars appears red in color because of refraction of light by its atmosphere, much like the color of the totally eclipsed Moon.

Answer:  FALSE

Diff: 2

Section Ref.:  6.6

20) There is new evidence that water has flowed as mud on Mars in recent times.

Answer:  TRUE

Diff: 2

Section Ref.:  6.6

 

21) Because of its axial tilt and more elliptical orbit, Mars’ polar caps change size even more than the Earth’s do.

Answer:  TRUE

Diff: 2

Section Ref.:  6.6

 

22) The seasonal polar caps on Mars, which grow and shrink over the year, are primarily carbon dioxide.

Answer:  TRUE

Diff: 1

Section Ref.:  6.6

 

23) Winds on Mars give rise to planet-wide dust storms.

Answer:  TRUE

Diff: 2

Section Ref.:  6.6, 6.8

 

24) The low surface gravity helps Martian volcanoes grow to great heights.

Answer:  TRUE

Diff: 1

Section Ref.:  6.6

 

25) The giant Borealis basin around the Martian north pole may have formed due to an impact with an asteroid twice the size of Ceres.

Answer:  TRUE

Diff: 2

Section Ref.:  6.6

 

26) The Phoenix lander on Mars failed to confirm the presence of water ice under the surface.

Answer:  FALSE

Diff: 1

Section Ref.:  6.6

 

 

27) Mercury has an unusually small core.

Answer:  FALSE

Diff: 2

Section Ref.:  6.7

 

28) Mars has a weak magnetic field.

Answer:  TRUE

Diff: 2

Section Ref.:  6.7

 

29) The Mars Rover found undisputed microfossils, proving life once existed on Mars.

Answer:  FALSE

Diff: 2

Section Ref.:  6.7

30) Venus and Mercury both have magnetic fields similar to Earth’s.

Answer:  FALSE

Diff: 2

Section Ref.:  6.7

 

31) Mercury’s magnetic field is generated by the same dynamo effect as Earth’s.

Answer:  FALSE

Diff: 3

Section Ref.:  6.7

 

32) Carbon dioxide is the predominant atmospheric gas on Venus.

Answer:  TRUE

Diff: 1

Section Ref.:  6.3, 6.8

 

33) Running water continues to be the major erosive factor of Mars today.

Answer:  FALSE

Diff: 2

Section Ref.:  6.6

 

34) Running water played a major role in shaping Mars in ancient times.

Answer:  TRUE

Diff: 2

Section Ref.:  6.6

 

 

35) Which of these gets so bright as to be seen in daylight at times?

  1. A) Mercury
  2. B) Venus
  3. C) Mars
  4. D) Jupiter
  5. E) Saturn

Answer:  B

Diff: 1

Section Ref.:  6.1

 

36) Which three worlds have almost identical densities?

  1. A) Mercury, Venus, and Earth
  2. B) Mercury, Mars, and our Moon
  3. C) Deimos, Phobos, and our Moon
  4. D) Earth, Moon, and Mars
  5. E) Mercury, Earth, and Mars

Answer:  A

Diff: 2

Section Ref.:  6.1

37) Which planet shows the widest range of surface temperatures between day and night?

  1. A) Mercury
  2. B) Venus
  3. C) Earth
  4. D) Mars
  5. E) Uranus

Answer:  A

Diff: 1

Section Ref.:  6.2

 

38) How does Mercury’s rotation relate to the Sun?

  1. A) It always keeps one face tidally locked toward the Sun, as our Moon does with us.
  2. B) Its year is much shorter, only 88 days, than its slow rotation of 243 days on its axis.
  3. C) Its rotation rate is 2/3 as long as its year, due to tidal resonances.
  4. D) Its day is the same length as its year.
  5. E) It does not spin at all, being tidal stopped by the solar tides.

Answer:  C

Diff: 2

Section Ref.:  6.2

 

 

39) Venus’ rotation on its axis

  1. A) is the fastest of the terrestrial planets.
  2. B) is clockwise, unlike most other solar system objects.
  3. C) shows it is tidally locked in its orbit around the Sun.
  4. D) is highly tilted to its orbital plane, causing large seasonal changes.
  5. E) prevents us from seeing all of its surface features.

Answer:  B

Diff: 2

Section Ref.:  6.2

 

40) Mercury presents the same side to the Sun

  1. A) every other orbit.
  2. B) all the time, just like our Moon.
  3. C) every 12 hours.
  4. D) every third orbit.
  5. E) twice every orbit.

Answer:  A

Diff: 3

Section Ref.:  6.2

 

41) The atmospheric pressure on Venus

  1. A) shows an extreme change with the seasons.
  2. B) is much lower than on Earth.
  3. C) is about the same as on Mercury.
  4. D) is much higher than on Earth.
  5. E) causes variations in surface temperature.

Answer:  D

Diff: 1

Section Ref.:  6.3

42) What is the main constituent of the atmosphere of Venus?

  1. A) oxygen
  2. B) nitrogen
  3. C) hydrogen
  4. D) carbon dioxide
  5. E) sulfuric acid

Answer:  D

Diff: 1

Section Ref.:  6.3

 

 

43) The main constituent of the Martian atmosphere is

  1. A) hydrogen.
  2. B) helium.
  3. C) methane.
  4. D) carbon dioxide.
  5. E) nitrogen.

Answer:  D

Diff: 1

Section Ref.:  6.3

 

44) Why are Mars’ seasons more extreme than those of the earth?

  1. A) Mars’ seas dried up long ago.
  2. B) Mars’ axial tilt is slightly more than our 23.5 degrees.
  3. C) Mars’ orbit is more eccentric than our almost circular one.
  4. D) Mars’ weather is affected by evaporation from the polar ice in its summer.
  5. E) All of these contribute to the huge seasonal changes that Mars experiences.

Answer:  E

Diff: 3

Section Ref.:  6.2, 6.6

 

45) Which body has the densest atmosphere?

  1. A) Mercury
  2. B) Venus
  3. C) Earth
  4. D) Mars
  5. E) our Moon

Answer:  B

Diff: 2

Section Ref.:  6.3

 

46) One of the effects of Mercury’s very slow spin is

  1. A) extreme variations in its surface temperature.
  2. B) an intensely powerful magnetic field.
  3. C) tectonic activity.
  4. D) wind patterns that are slow, but global in size.
  5. E) large variations in the size of its polar cap.

Answer:  A

Diff: 3

Section Ref.:  6.3

 

47) Mercury’s surface most resembles which of these?

  1. A) the Earth’s deserts
  2. B) the lunar far side
  3. C) the lunar mare
  4. D) Venus’ polar regions
  5. E) Mars’ deserts

Answer:  B

Diff: 2

Section Ref.:  6.4

 

48) The scarps on Mercury were probably caused by

  1. A) tectonic activity.
  2. B) meteorite bombardment.
  3. C) a tidal bulge.
  4. D) volcanism.
  5. E) the crust cooling and shrinking.

Answer:  E

Diff: 2

Section Ref.:  6.4

 

49) What did radar astronomers find in the polar regions of Mercury?

  1. A) rift valleys
  2. B) large mare basins, such as near our Moon’s south pole
  3. C) temperatures cold enough to allow thin sheets of water ice
  4. D) polar caps of dry ice that vary seasonally, much like Mars
  5. E) auroral displays much like Earth’s

Answer:  C

Diff: 2

Section Ref.:  6.3

 

50) Our most detailed maps of Venus come from

  1. A) the Magellan space probe.
  2. B) the Hubble Space Telescope.
  3. C) direct observation from Earth-based optical telescopes.
  4. D) manned landings.
  5. E) Earth-based radio telescopes.

Answer:  A

Diff: 1

Section Ref.:  6.5

 

 

51) The surface of Venus can be observed with

  1. A) the Mt. Wilson 100″ telescope.
  2. B) radar observations.
  3. C) most amateur telescopes.
  4. D) the Hubble Space Telescope.
  5. E) All of these have provided detailed observations about the surface of our sister planet.

Answer:  B

Diff: 2

Section Ref.:  6.5

52) What percentage of the surface of Venus could be characterized as continental-sized highlands?

  1. A) less than 10%
  2. B) about 30%, like the Earth
  3. C) 45%
  4. D) 75%
  5. E) 100%

Answer:  A

Diff: 2

Section Ref.:  6.5

 

53) Which statement is true of Venus’ surface?

  1. A) There are two continent sized uplands.
  2. B) It has remained unchanged for billions of years.
  3. C) Atmospheric pressure is very low.
  4. D) There is an extensive hydrosphere.
  5. E) There are no shield volcanoes.

Answer:  B

Diff: 2

Section Ref.:  6.5

 

54) Like Olympus Mons, volcanoes on Venus

  1. A) form where continental plates collide.
  2. B) are much larger than typical volcanoes on Earth.
  3. C) have been extinct for billions of years.
  4. D) only form at the equator.
  5. E) are shield volcanoes.

Answer:  E

Diff: 3

Section Ref.:  6.5

 

 

55) Valles Marineris is the most striking example of a(n)

  1. A) impact crater.
  2. B) shield volcano.
  3. C) oceanic trench.
  4. D) rift valley.
  5. E) scarp.

Answer:  D

Diff: 1

Section Ref.:  6.6

 

56) The deepest depression found on the surface of Mars is the

  1. A) Mariana Trench.
  2. B) Caloris basin.
  3. C) Valles Marineris rift.
  4. D) Hellas Basin.
  5. E) Mare Crisium.

Answer:  D

Diff: 1

Section Ref.:  6.6

57) We have not yet found meteoroids and meteorites derived from

  1. A) Venus.
  2. B) the Moon.
  3. C) Mars.
  4. D) asteroids.
  5. E) comets.

Answer:  A

Diff: 2

Section Ref.:  6.6

 

58) The name of the NASA mission(s) that landed on Mars in 1976 was

  1. A) Voyager.
  2. B) Magellan.
  3. C) Viking I and II.
  4. D) Venera 14.
  5. E) Galileo.

Answer:  C

Diff: 2

Section Ref.:  6.6

 

 

59) Which of the following characterizes a shield volcano?

  1. A) It sits above a hot spot in the planet’s mantle.
  2. B) It is formed by moving tectonic plates.
  3. C) It can erupt only briefly before being dragged off the hot spot.
  4. D) It cannot get as high as Mt. Everest before the thin crust starts slumping.
  5. E) It cannot grow very large, for it has a very short span of eruption.

Answer:  A

Diff: 2

Section Ref.:  6.5, 6.6

 

60) What is true of Mars?

  1. A) Its magnetic field is stronger than Earth’s
  2. B) Its atmosphere is mostly water vapor.
  3. C) Iron oxide on the surface is responsible for its reddish color.
  4. D) A pool of water was discovered by the Mars Rover.
  5. E) Definite microfossils have been found.

Answer:  C

Diff: 3

Section Ref.:  6.6

 

61) That the Tharsis region on Mars has so few craters

  1. A) proves tectonic activity is taking place.
  2. B) is due to the very low elevation of the region.
  3. C) suggests it is the youngest region on the planet.
  4. D) suggests it is at the center of a particularly strong magnetic field.
  5. E) is due to annual flooding and water erosion.

Answer:  C

Diff: 3

Section Ref.:  6.6

62) The largest difference between Mars’ northern and southern hemispheres is that

  1. A) the southern appears older, with more impact craters.
  2. B) the northern has all the outflows and must have been much hotter.
  3. C) the northern is higher overall, despite some high volcanoes in the south.
  4. D) the southern has a polar cap, but none ever forms in the north.
  5. E) the southern is much darker, with large mare-like basaltic lava flows.

Answer:  A

Diff: 3

Section Ref.:  6.6

 

 

63) The presence of a Mercurian magnetic field surprised the planetary scientists on the Mariner 10 team because

  1. A) Mercury is low in iron.
  2. B) Mercury spins too rapidly to produce a stable dynamo.
  3. C) it’s still too hot for its core to have differentiated.
  4. D) the dynamo theory predicted that Mercury was spinning too slowly for one.
  5. E) Mercury lacks an iron core.

Answer:  D

Diff: 2

Section Ref.:  6.7

 

64) Much of the water on Mars

  1. A) is thought to be in a layer of permafrost just below the surface.
  2. B) lies in shallow pools near the poles.
  3. C) is locked in the seasonal ice cap.
  4. D) is found in deep pools near the equator.
  5. E) is in the form of clouds.

Answer:  A

Diff: 2

Section Ref.:  6.9

 

65) Of all the planets known in antiquity, ________ is the hardest to observe visually.

Answer:  Mercury

Diff: 1

Section Ref.:  6.1

 

66) Compared to the orbits of Venus and Earth, the orbits of both Mercury and Mars have much ________ eccentricity.

Answer:  higher

Diff: 2

Section Ref.:  6.1

 

67) The only two planets which can transit the Sun are ________.

Answer:  Mercury and Venus

Diff: 2

Section Ref.:  6.1

 

68) The Sun’s tidal pull has slowed Mercury’s rotation down to a period ________ that of its year.

Answer:  2/3

Diff: 2

Section Ref.:  6.2

69) The direction of the rotation of Venus is exceptional because it is in a ________ direction.

Answer:  retrograde or clockwise

Diff: 1

Section Ref.:  6.2

 

70) The planet which shows us the widest range of surface temperatures between day and night is ________.

Answer:  Mercury

Diff: 1

Section Ref.:  6.2

 

71) Of all the planets, the axial tilt and rotation period of ________ is most like our own.

Answer:  Mars

Diff: 1

Section Ref.:  6.2

 

72) While featureless in visible light, we can see some detail in Venus’ clouds using ________.

Answer:  ultraviolet light

Diff: 3

Section Ref.:  6.2

 

73) Because of their low surface gravities, the Moon and Mercury lack ________.

Answer:  atmosphere

Diff: 1

Section Ref.:  6.3

 

74) The clouds on Venus are made primarily of ________.

Answer:  sulfuric acid.

Diff: 1

Section Ref.:  6.3

 

75) ________ are great wrinkle marks on Mercury’s crust, due to its core contracting.

Answer:  Scarps

Diff: 2

Section Ref.:  6.4

 

76) The surface of Mercury looks very similar to ________.

Answer:  the lunar far side

Diff: 2

Section Ref.:  6.4

 

77) The most effective wavelengths to see through the clouds of Venus to the surface are ________.

Answer:  radio or radar

Diff: 2

Section Ref.:  6.5

 

 

78) Smooth rolling plains, modest highlands and lowlands, and no water describes the surface of ________.

Answer:  Venus

Diff: 2

Section Ref.:  6.5

79) Unlike our Moon and Mars, all the impact craters found on Venus are ________ in size.

Answer:  large

Diff: 1

Section Ref.:  6.5

 

80) In age, the surface of Venus is much ________ than even the lunar mare.

Answer:  younger

Diff: 2

Section Ref.:  6.5

 

81) As with the lunar mare and Earth’s ocean basins, the chief rock in the low plains of Venus is ________.

Answer:  basalt

Diff: 1

Section Ref.:  6.5

 

82) Mars appears red due to ________ on its surface.

Answer:  rust, or iron oxide

Diff: 1

Section Ref.:  6.6

 

83) Of all the planets, only ________ has surface features easily seen from Earth with ground-based telescopes.

Answer:  Mars

Diff: 1

Section Ref.:  6.6, Disc. 6.1

 

84) The largest volcano in the solar system, ________, is found on Mars.

Answer:  Olympus Mons

Diff: 1

Section Ref.:  6.6

 

85) Directly opposite the Tharsis uplift and volcanoes on Mars lies the deep ________, perhaps suggesting impact cause and volcanic effect.

Answer:  Hellas basin

Diff: 3

Section Ref.:  6.6

 

 

86) Mercury’s core is unusually ________, which may help explain its magnetic field.

Answer:  large

Diff: 1

Section Ref.:  6.7

 

87) The planet ________ has the least variation in temperatures on the surface between day and night.

Answer:  Venus

Diff: 2

Section Ref.:  6.8

88) Carbon dioxide dominates the atmospheres of Venus and Mars, but on Earth most of it lies underground as ________.

Answer:  carbonate (or limestone) rocks

Diff: 2

Section Ref.:  6.8

 

89) The ALH84001,meteorite, discovered in Antarctica, came from ________, and suggests it may once have had life.

Answer:  Mars

Diff: 2

Section Ref.:  6.8

 

90) The greatest rift valley system yet found is ________ on Mars.

Answer:  Valles Marineris

Diff: 2

Section Ref.:  6.7

 

91) While ________ gas is the main atmospheric component of both Mars and Venus, its density means it plays a far larger role in heating Venus.

Answer:  carbon dioxide

Diff: 1

Section Ref.:  6.8

 

92) The great barometric changes accompany the sublimation of carbon dioxide in the Martian spring and summer, creating planet-wide ________.

Answer:  dust storms

Diff: 2

Section Ref.:  6.8

 

93) What is the primary effect the carbon dioxide in Venus’ atmosphere has on the planet?

Answer:  The high concentration of carbon dioxide has caused a runaway greenhouse effect that results in very high surface temperatures.

Diff: 2

Section Ref.:  6.8

 

 

94) Why is Venus’ rotation unusual?

Answer:  Venus is the only terrestrial planet to rotate retrograde (or backwards or clockwise) on its axis.

Diff: 1

Section Ref.:  6.2

 

95) What is unusual about the rotational (spin) and orbital periods of Venus?

Answer:  Venus’ day is actually longer than its year. It takes longer to spin once on its axis than to complete one orbit around the Sun.

Diff: 3

Section Ref.:  6.2, Appendix 3

 

96) If Mars’ atmosphere is mostly carbon dioxide, why isn’t it as hot as Venus?

Answer:  Although it has a carbon dioxide atmosphere, Mars’ atmosphere is very thin, much less dense than Venus’ or even Earth’s.

Diff: 1

Section Ref.:  6.3

97) How does the rotation of Venus’ clouds compare to the rotation of its surface?

Answer:  The clouds rotate much faster than the surface.

Diff: 3

Section Ref.:  6.3

 

98) Describe the relation between Mercury’s spin and orbit.

Answer:  One rotation of Mercury on its axis (its day) is exactly 2/3 of its orbital period (its year).

Diff: 2

Section Ref.:  6.2

 

99) Why is the atmospheric pressure at the surface of Venus so much higher than Earth’s?

Answer:  The atmosphere is much more massive than Earth’s and extends to a much greater height above the surface.

Diff: 1

Section Ref.:  6.3

 

100) Why do our best radar maps of Venus come from the Magellan space probe?

Answer:  Magellan went into orbit around Venus and used radar to penetrate the clouds and map the surface. Visual wavelength telescopes cannot see through the clouds.

Diff: 2

Section Ref.:  6.5

 

101) Why were the Russian Venera spacecraft so important to our understanding of Venus?

Answer:  They were the first spacecraft to soft land on the planet and send images of the surface back to Earth.

Diff: 3

Section Ref.:  6.5

 

102) What are coronae?

Answer:  large, circular volcanic upwellings on the surface of Venus

Diff: 3

Section Ref.:  6.5

 

103) Describe the primary difference between the northern and southern hemispheres on Mars.

Answer:  The northern hemisphere is primarily plains (lowlands) with few craters and extensive lava flows. The southern hemisphere is heavily cratered highlands.

Diff: 2

Section Ref.:  6.6

 

104) Where is most of the water on Mars believed to be?

Answer:  In the polar caps and a layer of permafrost just below the surface.

Diff: 2

Section Ref.:  6.6

 

105) How is the Mars Rover mission different from the Global Surveyor mapping mission?

Answer:  The Mars Rover mission landed two probes, Spirit and Opportunity, on the surface. They traveled over the surface collecting and analyzing samples. Global Surveyor was an orbiting spacecraft.

Diff: 2

Section Ref.:  6.6, 6.7

106) Other than its atmosphere, name two properties of Venus that are unique among the terrestrial planets.

Answer:  Venus rotates clockwise and has not been shown to have a magnetic field.

Diff: 2

Section Ref.:  6.2, 6.7

 

107) In what way is Mercury’s core unusual?

Answer:  Mercury has the largest core relative to the size of the planet.

Diff: 2

Section Ref.:  6.7

 

108) If its density suggests its core is similar to ours, why does Venus lack a magnetic field?

Answer:  Venus’ rotation is too slow to drive the dynamo effect that creates the magnetic field Earth has.

Diff: 3

Section Ref.:  6.7

 

109) What is the significance of large percentage of oxygen in Earth’s atmosphere?

Answer:  According to the way we believe the atmosphere evolved, the oxygen is an indication that life is present.

Diff: 2

Section Ref.:  6.8

 

 

110) Will Mars ever appear to the unaided eye as large as the Moon at closest approach? Explain.

Answer:  No. Mars is small, and even at closest approach it is so distant from Earth that it takes large telescopes with the best conditions to resolve surface features as small as 100 km across. With the unaided eye, Mars appears as a small point of reddish light shining more brightly than the stars.

Diff: 2

Section Ref.:  6.1, 6.6

 

111) While surface conditions differ greatly, name three ways that Venus and Earth are indeed “sister planets.”

Answer:  No other two planets in the solar system are so similar in size, mass, density, and surface gravity.

Diff: 2

Section Ref.:  6.1

 

112) When are Mercury and Venus easiest to observe from Earth? Why? How much of then can we see at that time?

Answer:  At greatest elongations, they rise farthest east and west of the Sun, and can be best seen in evening and morning twilight. But they will appear only half lit.

Diff: 2

Section Ref.:  6.1

113) How and why would the noon Sun appear different to an observer on Mercury compared to one on Earth?

Answer:  Mercury’s rotation axis is almost perpendicular to its orbit. This means the angle of the Sun with the southern (or northern) horizon never changes. On Mercury, an observer at the equator would always see the noon Sun overhead, an observer at the pole would always see it on the horizon. On Earth, the altitude of the Sun changes over the year because of the 23.5 degree axial tilt.

Diff: 3

Section Ref.:  6.2

 

114) Which terrestrial planets lack seasons? Why?

Answer:  Mercury and Venus are both so close to the Sun that it probably tidally locked their equators toward it. Without an axial tilt the angle of the Sun’s rays never changes so there are no seasons.

Diff: 3

Section Ref.:  6.2

 

 

115) On rare occasions, Mercury and Venus can transit the Sun, crossing directly between us and our Sun. If you were watching the event closely, such as on June 5, 2012, you might note a “tear-drop” effect as Venus came on and left the solar disk, very different from the disk of Mercury. Explain.

Answer:  Mercury is airless, but the dense Venusian atmosphere can refract sunlight, creating the bending of light noted in the “tear-drop.”

Diff: 3

Section Ref.:  6.3

 

116) If Venus’ clouds block much of the sunlight before it reaches the surface, why is the planet so hot?

Answer:  The carbon dioxide in the dense atmosphere creates a greenhouse effect. Some sunlight (and its energy) still reaches the surface and is reradiated as heat. Heat (or infrared radiation) is trapped beneath the atmosphere, causing an increase in the temperature at the surface.

Diff: 3

Section Ref.:  6.8

 

117) Contrast the compositions and heights of the clouds of Earth and Venus.

Answer:  Our clouds of water droplets occur in our troposphere, within about 12 km of the surface. On Venus, the much thicker upper-level cloud deck of sulfuric acid droplets lies about 50-70 km above its surface.

Diff: 3

Section Ref.:  5.3, 6.3

 

118) Why do we know much more about the surface of Mars than that of Venus?

Answer:  Venus has a thick cloud cover that prevents us from seeing the surface with visible light. Radar can map the surface, but its longer wavelength means the resolution is worse. Mars’ atmosphere is thin enough that we can see surface detail from Earth. Also, we have landed several spacecraft on Mars, some of which have traveled over the surface. The few spacecraft that made successful soft landings on Venus were very short lived.

Diff: 3

Section Ref.:  6.3, 6.6

119) Mars and Mercury are similar in size, and Mercury is even denser. Why then is it Mars that has more atmosphere?

Answer:  Its location is too close to the Sun; Mercury’s gases boil away in the solar wind. Colder Mars has enough gravity to hang on to more, even though its water is no longer liquid today.

Diff: 2

Section Ref.:  6.4

 

 

120) How are surfaces of Mercury and the Moon similar? Different? Why?

Answer:  Both are airless worlds with many ancient impact craters. On our Moon, the tides of Earth drew out the mare on the Earth side, while Mercury’s lava flows were much less extensive than the mare. But as its core cooled and shrank, Mercury’s crust developed huge scarps, great wrinkles that run for hundreds of miles.

Diff: 3

Section Ref.:  6.7

 

121) On our Moon, Mercury, Earth, and Mars, there are a variety of meteor craters in terms of size. Yet all those found on Venus are over 5 kilometers across. Explain.

Answer:  The atmosphere of Venus is much thicker, so that only the largest asteroids (probably at least a kilometer across) can survive the fiery transit of this dense atmosphere and arrive intact at the surface to create such damage. Only the strong survive.

Diff: 3

Section Ref.:  6.5

 

122) Mars is often called a “midway world,” similar in some respects to Earth, and in others to our Moon. Explain.

Answer:  Like our Moon, much of Mars is ancient cratered terrain, and its density is closer to that of the Moon than Earth. But like us, Mars has seasonal variations, polar caps, clouds, an atmosphere, dust storms, and signs of past liquid water and erosion.

Diff: 3

Section Ref.:  6.6

 

123) Our Moon and Mars both show very different hemispheres. Compare them and explain why this occurred in each case.

Answer:  The far side of our Moon and southern hemisphere of Mars are ancient and heavily cratered. The near side of the Moon has the striking mare, lava flows pulled out by our tides, while the northern hemisphere of Mars sits opposite the Hellas impact basin, and has great volcanoes on the Tharsis bulge and great plains, smoothed by either lava or water.

Diff: 3

Section Ref.:  6.7

 

124) Why was the discovery of a substantial magnetic field around Mercury a surprise? How was it detected?

Answer:  In its close passes by Mercury, Mariner 10 found a field that is much stronger than Mercury’s very slow rotation would have led us to expect with the dynamo theory.

Diff: 2

Section Ref.:  6.7

125) What, other than its existence, is unusual about the magnetic field of Mercury?

Answer:  It is still being generated, through an unknown process, and is significantly offset from the planet’s center.

Diff: 3

Section Ref.:  6.7

 

 

126) Relate Mercury’s scarps to the differentiation process.

Answer:  As Mercury was molten, the dense iron core formed from sinking iron and nickel. But smaller Mercury cooled off much faster than Earth, so its core cooled and started shrinking as it froze solid. This contraction caused the crust above to wrinkle and form the vast scarps that run across Mercury’s crust.

Diff: 2

Section Ref.:  6.4

 

127) The vast flood deposits prove Mars once had much running water. What happened to it?

Answer:  As Martian volcanism died down, the atmosphere became too thin for greenhouse gases to keep the water liquid. Most froze in the polar caps or as tundra underground, and some was also lost into space, like Venus lost its due to exposure to ultraviolet light.

Diff: 2

Section Ref.:  6.8

 

128) Contrast the atmosphere of Venus with its clouds.

Answer:  The atmosphere is almost entirely carbon dioxide, but the clouds are made of droplets of sulfuric acid, the result of water and sulfur dioxide erupting from its volcanoes chemically combining over time.

Diff: 2

Section Ref.:  6.8

 

129) What is the most abundant gas in the atmospheres of Mars and Venus? Explain why it is not as abundant in Earth’s atmosphere.

Answer:  The carbon dioxide so abundant on our neighbors was first dissolved in the Earth’s early water oceans, then deposited beneath them in carbonate rocks such as limestone. Also, photosynthesis took much of the remaining carbon dioxide and water and combined them to make carbohydrates and release oxygen into our unique atmosphere.

Diff: 3

Section Ref.:  6.8

 

130) Why isn’t there water on Venus?

Answer:  High temperatures and the runaway greenhouse effect drove water vapor high up in the atmosphere, where solar ultraviolet radiation split it into hydrogen and oxygen atoms. The light hydrogen boiled off into space, and the oxygen combined with crustal rocks.

Diff: 3

Section Ref.:  6.8

 

131) Water is one of the most common substances in the universe, and vital to us on Earth. What happened to it on Mars?

Answer:  At first, while erupting volcanoes thickened it, Mars’ atmosphere was dense enough to stay warm enough for liquid water to flow over much of Mars’ ancient surface. But as the core of Mars cooled down, volcanism declined, and Mars’ atmosphere lost much of its initial water to space, due to its less surface gravity then our own. Today there is still much water frozen in the polar caps and tundra, and on some occasions it melts fast enough to erupt as small mud flows imaged by the Mars Global Surveyor recently.

Diff: 3

Section Ref.:  6.8

 

Astronomy: A Beginner’s Guide to the Universe, 7e (Chaisson/McMillan)

Chapter 7   The Jovian Planets: Giants of the Solar System

 

1) A gravitational assist, or slingshot, can be used to either speed up or slow down a spacecraft.

Answer:  TRUE

Diff: 1

Section Ref.:  7.1

 

2) All nine planets in the solar system have been visited by spacecraft.

Answer:  FALSE

Diff: 1

Section Ref.:  7.1

 

3) William Herschel was the discoverer of Uranus.

Answer:  TRUE

Diff: 1

Section Ref.:  7.2

 

4) Galileo’s early telescopes revealed the four large moons of Jupiter, the rings of Saturn, and its large moon Titan.

Answer:  FALSE

Diff: 2

Section Ref.:  7.1

 

5) While Voyagers were probes that flew past in a few days, Galileo and Cassini are orbiters, designed to study Jupiter and Saturn over prolonged periods of time.

Answer:  TRUE

Diff: 2

Section Ref.:  7.1

 

6) Most of our detailed knowledge of the jovian planets comes from the Hubble Space Telescope.

Answer:  FALSE

Diff: 2

Section Ref.:  7.1

 

7) The Galileo probe was deliberately steered into Jupiter’s atmosphere, ending its mission.

Answer:  TRUE

Diff: 2

Section Ref.:  7.1

 

8) When Cassini entered orbit around Saturn, it caused the planet’s orbit to change.

Answer:  TRUE

Diff: 3

Section Ref.:  7.1, More Prec. 7.1

 

 

9) Like the discovery of Uranus, the finding of Neptune was accidental.

Answer:  FALSE

Diff: 1

Section Ref.:  7.2

10) Changes in the predicted motion of Uranus led to the search for an eighth planet.

Answer:  TRUE

Diff: 2

Section Ref.:  7.2

 

11) Saturn is less dense than water.

Answer:  TRUE

Diff: 1

Section Ref.:  7.3

 

12) All four jovian planets are made primarily of hydrogen and oxygen.

Answer:  FALSE

Diff: 1

Section Ref.:  7.3

 

13) Differential rotation is when a planet’s equatorial and polar regions rotate at different rates.

Answer:  TRUE

Diff: 1

Section Ref.:  7.3

 

14) All four jovian planets spin faster than any of the terrestrials.

Answer:  TRUE

Diff: 2

Section Ref.:  7.3

 

15) The equators of all four jovian planets rotate more rapidly than the polar regions.

Answer:  FALSE

Diff: 2

Section Ref.:  7.3

 

16) Jupiter’s axial tilt is similar to that of Mercury, while Saturn’s is more like ours.

Answer:  TRUE

Diff: 2

Section Ref.:  7.3

 

17) The rotation of the magnetic fields of the jovian planets is believed to also give us the rotation rate of the planet’s core.

Answer:  TRUE

Diff: 2

Section Ref.:  7.3

 

 

18) There is a clear relationship between the interior and atmospheric rotation rates of the jovian planets.

Answer:  FALSE

Diff: 2

Section Ref.:  7.3

 

19) The axial tilts of Uranus and Neptune are similar.

Answer:  FALSE

Diff: 2

Section Ref.:  7.3

20) Jupiter’s Great Red Spot is similar to a hurricane on Earth except for its size.

Answer:  TRUE

Diff: 1

Section Ref.:  7.4

 

21) Jupiter’s atmosphere looks uniform and calm, with no visible detail.

Answer:  FALSE

Diff: 1

Section Ref.:  7.4

 

22) The zonal flows giving rise to the belts and zones are similar to the jet streams in our own stratosphere.

Answer:  TRUE

Diff: 1

Section Ref.:  7.4

 

23) Although water and ammonia can produce Jupiter’s white clouds, the complex coloration we observe in Jupiter’s atmosphere requires more complex chemistry.

Answer:  TRUE

Diff: 2

Section Ref.:  7.4

 

24) The Galileo probe into Jupiter’s atmosphere found more water than expected.

Answer:  FALSE

Diff: 2

Section Ref.:  7.4

 

25) Helium is more abundant on Saturn than on Jupiter.

Answer:  FALSE

Diff: 2

Section Ref.:  7.5

 

 

26) Although it is almost the same size as Jupiter, Saturn’s gravity is about 2.5 times less, because of Saturn’s lower mass and density.

Answer:  TRUE

Diff: 2

Section Ref.:  7.3, 7.5

 

27) There is less ammonia in the atmospheres of Uranus and Neptune than in Jupiter or Saturn.

Answer:  TRUE

Diff: 2

Section Ref.:  7.5

 

28) Neptune has a larger fraction of methane in its atmosphere than Uranus.

Answer:  TRUE

Diff: 2

Section Ref.:  7.5

 

29) The less internal heat a jovian planet emits, the more it stirs up its clouds.

Answer:  FALSE

Diff: 2

Section Ref.:  7.5

30) The Great Dark Spot of Neptune is probably just as long-lived as the more famed Great Red Spot of Jupiter; both lie at about the same latitudes, and are about the same size, relative to their planet.

Answer:  FALSE

Diff: 2

Section Ref.:  7.5

 

31) Methane absorbs red light readily, so we would expect a planet with a mostly methane atmosphere to appear blue.

Answer:  TRUE

Diff: 3

Section Ref.:  7.5

 

32) All four jovian planets are oblate, with larger polar than equatorial diameters.

Answer:  FALSE

Diff: 1

Section Ref.:  7.6

 

33) We have observed a comet strike Jupiter.

Answer:  TRUE

Diff: 1

Section Ref.:  7.6

 

 

34) Most of Jupiter’s volume is probably in the form of liquid metallic helium.

Answer:  FALSE

Diff: 2

Section Ref.:  7.6

 

35) In keeping with its Greek god, Neptune probably contains a lot of water, in a slushy mantle ocean.

Answer:  TRUE

Diff: 2

Section Ref.:  7.6

 

36) Jupiter’s magnetic field is much stronger than Earth’s, and has a magnetic tail that extends beyond the orbit of Saturn.

Answer:  TRUE

Diff: 2

Section Ref.:  7.6

 

37) Aurorae like ours have been seen above the poles of Jupiter and Uranus.

Answer:  FALSE

Diff: 2

Section Ref.:  7.6

 

38) All four Jovian magnetic fields are good examples of the dynamo theory, with the magnetic fields aligned well with the planets’ rapid rotations.

Answer:  FALSE

Diff: 2

Section Ref.:  7.6

39) Jupiter puts back into space twice the energy it gets from the Sun.

Answer:  TRUE

Diff: 2

Section Ref.:  7.6

 

40) Uranus’ rotation axis is tipped over 98 degrees, so its magnetosphere is tipped over the same amount.

Answer:  FALSE

Diff: 2

Section Ref.:  7.6

 

 

41) Our most detailed knowledge of Uranus and Neptune comes from

  1. A) spacecraft exploration.
  2. B) the Hubble Space telescope.
  3. C) ground-based visual telescopes.
  4. D) ground-based radio telescopes.
  5. E) manned missions.

Answer:  A

Diff: 1

Section Ref.:  7.1

 

42) The spacecraft Cassini went into orbit around

  1. A) Jupiter.
  2. B) Saturn.
  3. C) Uranus.
  4. D) Neptune.
  5. E) Pluto.

Answer:  B

Diff: 1

Section Ref.:  7.1

 

43) The Galileo mission put a spacecraft into orbit around Jupiter. Which statement is true?

  1. A) The spacecraft crashed into the moon Europa.
  2. B) The spacecraft used a gravity assist from both Venus and Earth.
  3. C) A saltwater ocean was discovered on Jupiter.
  4. D) Intense magnetic fields were discovered in the asteroid belt.
  5. E) A probe was released which soft landed on Io.

Answer:  B

Diff: 2

Section Ref.:  7.1

 

44) Which three played a role in the finding of Neptune?

  1. A) Herschel, Hubble, and Einstein
  2. B) Newton, Einstein, and Tombaugh
  3. C) Adams, Leverrier, and Galle
  4. D) Bode, Herschel, and Fraunhofer
  5. E) Shapley, Hubble, and Whipple

Answer:  C

Diff: 2

Section Ref.:  7.2

 

45) Small deviations in a planet’s orbital motion

  1. A) show we don’t fully understand gravitational forces yet.
  2. B) indicate the presence of an extensive atmosphere.
  3. C) indicate the presence of a powerful magnetic field.
  4. D) imply the nearby presence of a massive body.
  5. E) show the planet’s orbit isn’t stable.

Answer:  D

Diff: 2

Section Ref.:  7.2

 

46) Adams and Leverrier both predicted the position of Neptune, based on its effects on

  1. A) the Sun.
  2. B) Jupiter.
  3. C) Saturn.
  4. D) Uranus.
  5. E) Pluto.

Answer:  D

Diff: 2

Section Ref.:  7.2

 

47) Uranus was discovered

  1. A) by Galileo.
  2. B) thousands of years ago.
  3. C) with a radio telescope.
  4. D) after examining perturbations in Neptune’s orbit.
  5. E) less than 250 years ago.

Answer:  E

Diff: 2

Section Ref.:  7.2

 

48) At which planet can the pole remain in darkness for 42 years, then have 42 years of constant daylight?

  1. A) Jupiter
  2. B) Saturn
  3. C) Uranus
  4. D) Neptune
  5. E) Pluto

Answer:  C

Diff: 1

Section Ref.:  7.3

 

 

49) In terms of axial tilt, which of the jovian planets shows us the largest inclination?

  1. A) Jupiter
  2. B) Saturn
  3. C) Uranus
  4. D) Neptune
  5. E) Pluto

Answer:  C

Diff: 1

Section Ref.:  7.3

50) If you could find a bathtub big enough for Saturn, the planet would

  1. A) precipitate more helium.
  2. B) float.
  3. C) explode due to its liquid metallic hydrogen.
  4. D) catch fire, as liquid sodium reacts with water.
  5. E) sink due to its metallic interior.

Answer:  B

Diff: 1

Section Ref.:  7.3

 

51) The planet whose pole was facing the Sun when Voyager 2 approached in 1986 was

  1. A) Jupiter.
  2. B) Saturn.
  3. C) Uranus.
  4. D) Neptune.
  5. E) Mars.

Answer:  C

Diff: 1

Section Ref.:  7.3

 

52) Jupiter and the other jovian planets are noticeably oblate because

  1. A) they all have strong magnetic fields that deform their shape.
  2. B) their powerful gravity acts stronger on the closer poles than the distant equator.
  3. C) they are fluid bodies that are spinning rapidly.
  4. D) they are tidally distorted by the pulls for their satellite systems.
  5. E) All of the above are correct.

Answer:  C

Diff: 2

Section Ref.:  7.3

 

 

53) Cometary impacts with Jupiter

  1. A) are impossible to observe from Earth.
  2. B) have been observed from Earth at least twice.
  3. C) are extremely rare.
  4. D) are spectacular but do not teach us much.
  5. E) would not be catastrophic if they happened on Earth.

Answer:  B

Diff: 2

Section Ref.:  Discovery 7.2

 

54) Which of these is true about the seasons of Uranus?

  1. A) With a tilt of 29 degrees, they are not that different from our solstices and equinoxes.
  2. B) Its strange tilt produces extreme seasonal variations, especially at the poles.
  3. C) At the Uranian equator, the Sun would pass overhead every sixteen hours.
  4. D) At the Uranian pole the Sun sets every 16 hours during the summer and winter.
  5. E) There are no seasons at the poles.

Answer:  B

Diff: 2

Section Ref.:  7.3

55) The reason the jovian planets lost very little of their original atmosphere is due to their

  1. A) rapid rotation.
  2. B) strong magnetic fields.
  3. C) ring systems.
  4. D) large mass.
  5. E) many moons.

Answer:  D

Diff: 2

Section Ref.:  7.3

 

56) Compared to Saturn, Jupiter is about

  1. A) half as massive and denser.
  2. B) three times more massive and denser.
  3. C) 100 times more massive.
  4. D) twice the diameter, but less dense.
  5. E) half as dense, but the same mass since it is larger.

Answer:  B

Diff: 2

Section Ref.:  7.3

 

 

57) Studying the magnetospheres of the jovian planets has allowed us to measure their

  1. A) interior rotation rates.
  2. B) orbital periods.
  3. C) orbital radius.
  4. D) gravity.
  5. E) ring system diameters.

Answer:  A

Diff: 2

Section Ref.:  7.3

 

58) Essentially, the Great Red Spot is

  1. A) Neptune’s largest atmospheric feature.
  2. B) a large cyclonic storm (hurricane).
  3. C) always located within 10 degrees of Jupiter’s north pole.
  4. D) composed primarily of iron oxide.
  5. E) traveling north and south across Jupiter’s face.

Answer:  B

Diff: 1

Section Ref.:  7.4

 

59) Alternating zones of rising and sinking gas in Jupiter’s atmosphere

  1. A) create light and dark bands.
  2. B) cause Jupiter’s magnetic field to ripple.
  3. C) produced the ring system discovered by Voyager.
  4. D) generate magnetic fields.
  5. E) circle the planet from pole to pole.

Answer:  A

Diff: 3

Section Ref.:  7.4

60) The only probe into the atmospheres of any jovian planet was launched by

  1. A) Voyager 2 into Titan’s atmosphere.
  2. B) Pathfinder into Mars’ atmosphere.
  3. C) Cassini into Saturn’s clouds.
  4. D) Galileo into Jupiter’s equatorial zone.
  5. E) Huygens into Saturn’s equatorial belt.

Answer:  D

Diff: 3

Section Ref.:  7.4

 

 

61) The two outer jovian planets appear bluish in color because

  1. A) methane gas in their atmospheres absorbs red light well.
  2. B) ammonia absorbs blue light well.
  3. C) hydrogen and helium are both blue in large concentrations.
  4. D) dust motes in their atmospheres scatter blue well, just as in our own blue sky.
  5. E) from their distance, the Sun would appear hotter and bluer than from Earth.

Answer:  A

Diff: 1

Section Ref.:  7.5

 

62) Which common gas is less abundant in the top of Saturn’s atmosphere, compared to what we observe at Jupiter?

  1. A) hydrogen
  2. B) helium
  3. C) nitrogen
  4. D) methane
  5. E) argon

Answer:  B

Diff: 2

Section Ref.:  7.5

 

63) Why does Saturn radiate even more excess heat than Jupiter?

  1. A) Only Saturn is still radiating heat left over from its formation.
  2. B) Saturn’s thick clouds give it a stronger greenhouse effect.
  3. C) Helium rain falling inward generates heat as it descends.
  4. D) Saturn’s atmosphere contains much methane, which is very flammable.
  5. E) Saturn is more massive than Jupiter, so its gravitational compression is stronger.

Answer:  C

Diff: 2

Section Ref.:  7.6

 

64) Which planet had the Great Dark Spot in 1989, but had lost it by 1995?

  1. A) Jupiter
  2. B) Saturn
  3. C) Uranus
  4. D) Neptune
  5. E) Mars

Answer:  D

Diff: 2

Section Ref.:  7.5

 

65) Of the jovian planets, which generates the least internal heat?

  1. A) Jupiter
  2. B) Saturn
  3. C) Uranus
  4. D) Neptune
  5. E) Pluto

Answer:  C

Diff: 2

Section Ref.:  7.6

 

66) The magnetic field tilts of which two bodies are the most unusual?

  1. A) Mercury and Earth
  2. B) Jupiter and Saturn
  3. C) Uranus and Neptune
  4. D) Saturn and Pluto
  5. E) Mars and Saturn

Answer:  C

Diff: 2

Section Ref.:  7.6

 

67) What is the source of Jupiter’s intense radio waves and magnetism?

  1. A) charged particles trapped in Jupiter’s solid iron core similar to Earth
  2. B) liquid metallic hydrogen swirling in the rapidly spinning mantle
  3. C) the ionized sulfur ejected into a torus around Jupiter by Io
  4. D) the auroral displays in the polar regions, just like with Earth
  5. E) a liquid iron and nickel outer core, just like Earth’s magnetic field

Answer:  B

Diff: 2

Section Ref.:  7.6

 

68) Jupiter gives back into space twice the energy it gets from the distant Sun. Where is this energy coming from, for the most part?

  1. A) the impact energy of comets like SL-9
  2. B) helium rain descending into its mantle and core
  3. C) the slow escape of gravitational energy left from its formation
  4. D) the radioactive decay of U-238 in its iron-rich core, just as with the Earth
  5. E) the combined tidal stress of all four large Galilean moons

Answer:  C

Diff: 2

Section Ref.:  7.6

 

 

69) What is true of Jupiter’s magnetosphere?

  1. A) Although its surface field is greater, since the planet is larger the total field is actually weaker than Earth’s.
  2. B) It does not trap protons and electrons, as Earth’s Van Allen belts do.
  3. C) It has a tail that extends at least to Saturn’s orbit.
  4. D) It is most extensive on the sunward side of the planet.
  5. E) It is only slightly stronger than Saturn’s.

Answer:  C

Diff: 2

Section Ref.:  7.6

70) What is thought to lie at the center of Jupiter?

  1. A) a hot sea of liquid metallic hydrogen
  2. B) a solid core of crystalline helium
  3. C) a massive core of rocky materials with some iron mixed in
  4. D) gaseous hydrogen and helium, for Jupiter is not differentiated like Earth
  5. E) a fusion core like the Sun’s, with hydrogen being turned into helium

Answer:  C

Diff: 2

Section Ref.:  7.6

 

71) Which two jovian planets have magnetic field tilts that are not along their rotation poles?

  1. A) Jupiter and Saturn
  2. B) Jupiter and Uranus
  3. C) Saturn and Neptune
  4. D) Uranus and Neptune
  5. E) All jovian planets have magnetic fields close to their rotational axes.

Answer:  D

Diff: 2

Section Ref.:  7.6

 

72) In brightness, Jupiter is second only to the planet ________ most of the time.

Answer:  Venus

Diff: 1

Section Ref.:  7.1

 

73) In the telescope, ________ shows the most turbulent atmosphere, with changes easily seen even with amateur telescopes.

Answer:  Jupiter

Diff: 1

Section Ref.:  7.1

 

74) The most famous and long lasting storm in the solar system is ________.

Answer:  (Jupiter’s) Great Red Spot

Diff: 1

Section Ref.:  7.1

 

75) Jupiter is largest and brightest in our skies when seen at ________.

Answer:  opposition

Diff: 2

Section Ref.:  7.1

 

76) A “gravitational slingshot” enables a spacecraft to ________.

Answer:  speed up, or slow down, or change direction.

Diff: 2

Section Ref.:  7.1

 

77) Adams and Leverrier predicted the position of ________, which Galle confirmed.

Answer:  Neptune

Diff: 1

Section Ref.:  7.2

78) William Herschel discovered the green disk of ________ as the first telescopic planet.

Answer:  Uranus

Diff: 1

Section Ref.:  7.2

 

79) While Saturn is almost as large as Jupiter, its mass is only about ________ of Jupiter’s.

Answer:  one-third

Diff: 1

Section Ref.:  7.3

 

80) The oblateness of the jovian planets’ disks is caused by their ________.

Answer:  rapid rotations

Diff: 1

Section Ref.:  7.3

 

81) Compared to the terrestrial planets, the jovian planets have ________ average densities.

Answer:  low.

Diff: 1

Section Ref.:  7.3

 

82) Of the planets, ________ is the least dense, and could float on water.

Answer:  Saturn

Diff: 1

Section Ref.:  7.3

 

83) The oblateness of the jovian planets’ disks refers to their ________ equatorial diameters, compared to the polar diameters.

Answer:  larger

Diff: 1

Section Ref.:  7.3

 

 

84) Like Jupiter’s, Saturn’s rotation is fast and differential, with the ________ rotating fastest.

Answer:  equator

Diff: 1

Section Ref.:  7.3

 

85) Unlike Jupiter and Saturn, at Uranus and Neptune the ________ rotates the slowest.

Answer:  equator

Diff: 2

Section Ref.:  7.3

 

86) In general, wind direction ________ between adjacent bands in Jupiter’s atmosphere.

Answer:  alternates

Diff: 2

Section Ref.:  7.4

 

87) Jupiter’s bright zones are cloud streams made of ________ ice crystals.

Answer:  ammonia

Diff: 1

Section Ref.:  7.4

88) Jupiter’s darker ________ are complex in color and origin, with complex organic molecules including carbon, sulfur, and nitrogen.

Answer:  belts

Diff: 1

Section Ref.:  7.4

 

89) The Great ________ Spot of Neptune was striking in 1989, but gone by 1995.

Answer:  Dark

Diff: 1

Section Ref.:  7.5

 

90) Uranus and ________ are very similar in size, mass, and color.

Answer:  Neptune

Diff: 1

Section Ref.:  7.5

 

91) The most abundant molecule in Saturn’s atmosphere is ________.

Answer:  hydrogen.

Diff: 1

Section Ref.:  7.5

 

92) ________ looked very bland in Voyager 2 photos in 1986, but as equinox approached in the 1990s, its disk showed belts, zones, and storms.

Answer:  Uranus

Diff: 1

Section Ref.:  7.5

 

93) The white zones of Jupiter and Saturn are made of ________ ice, apparently dissolved in the deep oceans of Uranus and Neptune.

Answer:  ammonia

Diff: 1

Section Ref.:  7.5

 

94) Because it has a higher percentage of ________, Neptune appears even bluer than Uranus.

Answer:  methane

Diff: 1

Section Ref.:  7.5

 

95) Methane gas absorbs the color ________, accounting for the colors of Uranus and Neptune.

Answer:  red

Diff: 2

Section Ref.:  7.5

 

96) Compared to Jupiter, the element ________ is notably less common in Saturn’s atmosphere, perhaps condensing to fall toward the core as rain.

Answer:  helium

Diff: 2

Section Ref.:  7.5

97) Compared to Jupiter, Saturn’s east-west zonal (band) flow is ________.

Answer:  more stable or faster.

Diff: 2

Section Ref.:  7.5

 

98) While the mantles of Jupiter and Saturn are made of liquid metallic hydrogen, the mantles of Uranus and Neptune are chiefly ________.

Answer:  water (and ice)

Diff: 1

Section Ref.:  7.6

 

99) Jupiter radiates twice as much energy as it receives from solar light; the source of this “excess” energy is ________.

Answer:  gravitational contraction

Diff: 1

Section Ref.:  7.6

 

100) While ________ rotation axis is only tilted 29 degrees, its magnetic fields are just as strange as its twin’s.

Answer:  Neptune’s

Diff: 1

Section Ref.:  7.6

 

 

101) Their magnetic fields should originate in the planets’ ________, but those of Uranus and Neptune don’t even come close.

Answer:  cores

Diff: 1

Section Ref.:  7.6

 

102) Jupiter’s magnetic field is produced in its rapidly spinning mantle of ________.

Answer:  liquid metallic hydrogen

Diff: 2

Section Ref.:  7.6

 

103) How are Jupiter and Saturn similar?

Answer:  Both are about the same size, with oblate disks due to rapid rotation, striped with white zones and brownish belts.

Diff: 1

Section Ref.:  7.1

 

104) Name two space probes to the jovian planets and their destinations.

Answer:  Voyager I to Jupiter and Saturn, Voyager 2 to all four jovians, Galileo to Jupiter, Cassini to Saturn.

Diff: 1

Section Ref.:  7.1

 

105) Contrast the destinations of the probes dispatched by the Galileo and Cassini missions.

Answer:  Galileo‘s probe fell into the atmosphere of Jupiter, soon to be destroyed by heat and pressure. Cassini‘s probe, built by the ESA, was sent into the atmosphere of Saturn’s moon, Titan.

Diff: 1

Section Ref.:  7.1

106) Describe how the motion of Uranus led to the discovery of Neptune.

Answer:  Uranus at first was moving faster than predicted, then after 1822 mysteriously slowed down, as it had passed Neptune and was now pulled back by Neptune’s gravity. Adams and Leverrier used this perturbation to predict the position of Neptune, which Galle used to telescopically locate its blue disk.

Diff: 3

Section Ref.:  7.2

 

107) Contrast the rotation rates of the jovian planets with the terrestrial planets.

Answer:  All four jovian planets have a much faster rotation rate than any of the Terrestrial planets.

Diff: 1

Section Ref.:  7.3

 

 

108) Contrast the differential rotations of the four jovian planets. Explain.

Answer:  At Jupiter and Saturn, the equators rotate the fastest, but at Uranus and Neptune, the higher latitudes rotate faster than the equator. We do not yet understand this.

Diff: 3

Section Ref.:  7.3

 

109) Uranus and Neptune are often called twin worlds. How do their axial tilts differ?

Answer:  At 98 degrees, Uranus is flopped over on its side, and can have its pole pointing directly at the Sun, as it did when Voyager 2 passed it in 1986. Neptune’s tilt is a more normal 29 degrees.

Diff: 3

Section Ref.:  7.3

 

110) What element is notably deficient in Saturn’s atmosphere, and why?

Answer:  Helium seems to be condensing and raining downward toward Saturn’s mantle.

Diff: 2

Section Ref.:  7.5

 

111) What common gas assumes an uncommon state in the mantles of Jupiter and Saturn? Why?

Answer:  Hydrogen. On Earth hydrogen is a gas because of the pressure and temperature in our atmosphere. On Jupiter and Saturn, it can be liquid and have the properties of a metal because of the much higher temperatures and pressures.

Diff: 2

Section Ref.:  7.6

 

112) In what ways are the magnetic fields of Uranus and Neptune unusual?

Answer:  Unlike the magnetic fields of Earth, Jupiter, and Saturn, the fields of Uranus and Neptune are not aligned with the rotational axis of their planet. Additionally, both fields are offset from their planet’s center by a significant amount.

Diff: 3

Section Ref.:  7.6

 

113) Why do Uranus and Neptune appear bluish?

Answer:  Methane absorbs red light, and is common in their atmospheres.

Diff: 3

Section Ref.:  7.6

114) Compare and contrast the Galileo and Cassini missions.

Answer:  Both are orbiters of jovian planets, but the probe for Galileo fell into Jupiter’s atmosphere, while the Huygens probe from Cassini was sent to Saturn’s large moon Titan. Both used a gravitational slingshot via Earth and Venus to reach their destinations, resulting in reduced fuel consumption and possibly a longer than expected useful life. Cassini was able to collect data on Jupiter as it flew past.

Diff: 2

Section Ref.:  7.1

 

 

115) Why was Voyager 2 an extremely efficient and productive probe?

Answer:  Using gravitational assists, Voyager 2 was able to visit all four jovian planets, making many discoveries along the way. In effect, one spacecraft performed the equivalent of four missions.

Diff: 2

Section Ref.:  7.1

 

116) Compare the differential rotation rates of the four jovian planets.

Answer:  Jupiter and Saturn rotate rapidly, in about ten hours, with their equators spinning fastest. Both Uranus and Neptune spin slower (but still faster than Earth), and their equators spin slower than their higher latitudes.

Diff: 2

Section Ref.:  7.3

 

117) Discuss the seasons of Uranus.

Answer:  Flopped over with a 98 degree tilt, Uranus’ pole was pointing toward the Sun at solstice in 1986 when Voyager 2 flew past. With one hemisphere in constant daylight, the atmosphere was very bland. But by equinox in 2008, the whole planet was receiving eight hours of day and night, and the heating patterns were producing more normal jovian belts and zones. At each pole, you would get 42 years of constant Sun, then 42 years of darkness.

Diff: 2

Section Ref.:  7.3

 

118) How might the odd tilt of Uranus have been produced?

Answer:  As with the making of our Moon and Earth’s axial tilt, a large impact is possibly the factor that flipped Uranus over on its side.

Diff: 2

Section Ref.:  7.3

 

119) Contrast the compositions of Jupiter’s belts and zones.

Answer:  The zones are high, cold regions of ammonia ice crystals, white in color. But the lower, warmer belts are brownish from complex chemistry involving hydrogen sulfide, ammonia, and other chemicals.

Diff: 2

Section Ref.:  7.4

120) Discuss the roles that ammonia, hydrogen sulfide, and methane play in the appearances of the jovian planets.

Answer:  White ammonia ice makes up the zones of Jupiter and Saturn, and combines with hydrogen sulfide and other chemicals to make up the brownish belts. But it is not as common at Uranus and Neptune, perhaps instead dissolved in their water mantles. At Uranus and Neptune, methane is the chief coloring agent, absorbing red light strongly, and reflecting the blue light back into space.

Diff: 2

Section Ref.:  7.5

 

 

121) Name two ways the magnetic fields of Uranus and Neptune defy the normal behavior of planetary magnetic fields.

Answer:  Their fields are tilted very far off the rotation axes of both planets; most other planets have fields within 10 degrees of their poles. Neither field goes directly through the core of its planet, while all other fields seem to originate in the cores of their planets.

Diff: 2

Section Ref.:  7.6

 

122) Contrast the Great Red and Great Dark Spots.

Answer:  Both storms are oval, and lie at mid-southern latitudes. But Jupiter’s Great Red Spot has been continuously observed since we had telescopes that could spot it, while the Great Dark Spot was prominent for Voyager 2 in 1989, but had vanished from the disk of Neptune by 1995.

Diff: 3

Section Ref.:  7.6

 

123) Describe the interaction between Jupiter and Comet Shoemaker-Levy 9.

Answer:  When the comet passed close to Jupiter in 1992, gravitational tidal forces tore the nucleus apart, leaving it in fragments. On its approach in 1994, it struck the planet. Vibrations in the interior and atmospheric effects lasted for days. Huge fireballs were observed from Earth. Debris from the comet spread completely around the planet, taking years to settle out.

Diff: 3

Section Ref.:  7.6, Disc. 7.1