ASTRONOMY 121 - Winter 2005 Exam II Answers - VERSION A 1. A shield volcano is b. a volcano produced by repeated eruptions of lava 2. Jupiter and Saturn are noticeably oblate (bulging out at the equator) because: c. They rotate rapidly 3. What is the source of Jupiter's excess energy? d. The slow escape of gravitational energy, which heated the planet's interior during its formation 4. What is thought to lie at the center of Jupiter? b. A massive core of rocky material 5. What would Jupiter have needed to have become a star? b. More mass 6. The first spacecraft to soft-land on Venus was c. Venera 7 7. The axial tilt of Venus is about d. 177 degrees 8. Large volcanoes on Mars result from? d. Its low surface gravity 9. The surface gravity on Venus is about a. 90% of the surface gravity on Earth 10. On Venus, one solar day would be c. 243 Earth da 11. Which of the following is true? d. a storm system in Jupiter's atmosphere is much longer-lived than storms on Earth 12. The belts of Jupiter are best described as follows: a. Regions of downward moving material and low pressure 13. The semi-major axis of Jupiter is about b. 5.2 AU 14. The major moons of Jupiter can be grouped into four sets. Which set has the largest mass? b. next to inner set 15. One set of Jupiter's moons has retrograde orbits. It is the d. outer set 16. What is Io noted for c. It is the densest and most geologically active moon in the Solar System 17. The mass of Jupiter is equivalent to about d. 318 Earth masses 18. The average density of Jupiter is about a. 1300 kg/m3 19. What is thought to be the cause of Io's volcanoes? c. Gravitational forces from both Jupiter and Europa 20. What region(s) of Jupiter and Saturn's interiors generate their magnetic fields? b. The liquid metallic hydrogen 21. What is Europa noted for d. It has a liquid ocean below its cracked icy surface 22. Jupiter's atmosphere is composed mostly of c. hydrogen and helium 23. Which of the following statements describes the magnetic fields of Mercury and Venus? a. Mercury has a small field and Venus has no detectable field 24. What is the main constituent of the atmosphere of Venus? d. Carbon dioxide 25. Which of the following contributes to Venus' surface being so hot? a. It is closer than Earth to the Sun b. Its atmosphere is dense c. Its atmosphere is made almost entirely of carbon dioxide ---> d. all of the above 26. If Venus once had an ocean, where did it go? b. The water broke into hydrogen and oxygen, and the hydrogen escaped to space 27. Why is the Earth's atmosphere much less dense than Venus' a. Carbon dioxide on Earth is absorbed in the oceans and rocks 28. What is thought to have caused the craters on Venus? a. Most are volcanic in origin; some are due to meteoritic impacts 29. Various observations suggest there is on-going volcanic activity on Venus. Which of the following has NOT been observed. b. Active flowing lava fields on Venus 30. The rotation period of Jupiter is about a. 10 hours 31. The lack of a magnetic field on Venus probably stems from the planet’s: c. Slow rotation 32. What result does the greenhouse effect have on the surface environment of Venus? d. It has raised the surface temperature by hundreds of degrees Kelvin 33. How massive is Venus' atmosphere d. Ninety times as massive as Earth's 34. The distance from the Sun to Saturn is about b. 10 AU 35. What is Percival Lowell noted for? c. Interpretation of Mars' canals 36. Venus has a feature named Ishtar Terra. What is this feature? c. A continental-sized plateau 37. What is the name of the space probe that has sent back the most extensive data about the surface topography of Venus? a. Magellan 38. Saturn's outer atmosphere has a noticeable deficiency (relative to Jupiter) in which element? b. helium 39. The Martian satellites are likely b. captured asteroids 40. What did the Viking missions discover? d. Large concentrations of iron 41. The tilted axis of Mars results in? d. seasons 42. When is Mars brightest in the Earth's sky? a. when it is at opposition 43. The third brightest object in the sky b. Venus 44. The best evidence that water once existed in great quantities on Mars a. the runoff and outflow channels 45. What is the best description of the Mariner Valley c. a super-Grand Canyon on Mars 46. The interest in evidence for life on Mars was increased a few years ago by a. a rock from Mars found in Antarctica 47. How is the Roche limit defined? a. The critical distance from a planet, inside of which a moon can be tidally destroyed 48. A 2:1 resonance with Mimas causes a. The Cassini Division 49. Shepherd satellites are defined as a. Moons that confine a narrow ring 50. The Martian atmosphere is b. much thinner than the atmosphere of the Earth 51. Mass differentiated on Mars ____________ Earth b. less extensively than on 52. What evidence suggests to astronomers that Mars has a layer of permafrost just below the surface? b. the appearance that liquids flowed from craters when they were formed 53. The distance of Mars from the Sun is about c. 1.5 AU 54. The orbital period of Mars is d. 687 Earth days 55. The radius of Mars is about a. 0.53 Earth radii 56. The average density of Mars is about c. 3900 kg/m3 57. The rotation period of Mars is about b. 24 hours 58. Which of the following features is not observed on Mars? c. flowing rivers 59. Olympus Mons is c. the largest volcano in the Solar System 60. What is the Tharsis bulge? b. a large region on Mars that rises above the rest of the surface 61. When we see Saturn's rings edge-on, they seem to nearly disappear. We can thus conclude that the rings are b. very thin 62. The largest moon of Saturn is d. Titan 63. Why does Saturn radiate much more energy than it receives from the Sun? c. Helium rain gives off heat as it falls toward Saturn's center 64. What are Saturn's rings? d. Icy particles of a range of sizes moving in orbit around Saturn 65. Deimos is d. an asteroid captured by Mars 66. Titan is an interesting moon because a. Beneath its clouds, Titan may be Earth-like, in some respects b. It has a rich atmosphere that may resemble in some ways that of the early Earth c. It has the densest atmosphere of any moon in the Solar System ---> d. all of the above 67. Saturn has _______ moons. d. at least eighteen 68. The dark band in Saturn's rings was discovered by c. Cassini 69. Saturn's surface magnetic field is b.. roughly comparable to the Earth's 70. The NASA/ESA orbiter which arrived at Saturn in 2004 is named: d. Cassini 71. The atmosphere of Saturn is composed mostly of: b. hydrogen and helium 72. The atmosphere of Titan is composed mostly of: d. nitrogen 73. A critical difference between Jupiter and Saturn is that: d. Jupiter is three times more massive 74. If you could find a bathtub big enough for Saturn, the planet would: b. float 75. The Huyge's probe landed on Satur's largest moon on c. January 14, 2005 76. The rovers Spirit and Opportunity have explored the surface of b. Mars 77. Relative to Jupiter, Saturn has a semi-major axis that is c. about double 78. Saturn’s semi-major axis (in AU) cubed is b. equivalent to the square of it period (in Earth years) 79. Regarding the density of the planets a. Jupiter has a density of about 1300 kg/m3 b. Saturn has a density of about 680 kg/m3 c. Venus has a density of about 5240 kg/m3 ---> d. All of the above 80. The surface temperature of Saturn is about a. 100 K 81. The mass of Venus is d. 82% that of Earth 82. The mass of Mars is a. 11% that of Earth 83. Phobos is b. an asteroid captured by Mars 84. Which of the following played the most important role in the formation of Saturn’s rings? b. Saturn's Roche limit 87. What is the most common molecule in the Martian atmosphere? CO2 or Carbon Dioxide 88-89. Name the two moons of Mars: Phobos Diemos 90-91. What is the name of the largest moon in the Solar System, and about which planet does it revolve? Ganymede Jupiter 92. What is the most abundant element in the atmospheres of Jupiter and Saturn? Hydrogen 93. If Titan has oceans, they are made chiefly of liquid ______________. Methane 94. Saturn radiates more energy than it receives from ______________. The Sun 95. What is the main element in the atmosphere of Titan? Nitrogen