Astronomy Ch. 12
22. Most asteroids are closest in shape to a. a potato. b. a banana. c. a hot dog. d. a stick. e. a baseball.
A
30. What is the relative importance of collisions between comets compared to collisions between meteoroids and asteroids? a. They are not very important. b. They are very important. c. They are somewhat important, especially for short-period comets. d. They are only important for long-period comets.
A
33. Identify the object shown in the figure below. a. an active comet b. a meteor shower c. a meteorite d. an asteroid e. zodiacal dust
A
38. Comet Halley is unique because a. it was the first comet whose return was predicted. b. it is a member of the Jovian family but has a retrograde orbit. c. its period is less than a human lifetime. d. it was successfully visited by a spacecraft. e. it was the brightest comet ever observed by humans.
A
40. The nucleus of the typical comet is approximately _________ in size. a. 10 km b. 1,000 km c. 100 m d. 10 m e. 1 cm
A
5. Pluto is classified as a dwarf planet because a. it has not cleared out other bodies from its orbit. b. it is more than 1,000 times smaller than Earth's moon. c. it has no moons of its own. d. it has a unique chemical composition that is very different from other planets. e. it orbits just outside the Solar System.
A
61. The most common type of meteorites are a. stony meteorites. b. iron meteorites. c. achondrite meteorites. d. stony-iron meteorites. e. carbonaceous chondrite meteorites.
A
62. Which group of meteorites represents the conditions in the earliest stages of the formation of the Solar System? a. chondrites b. achondrites c. icy meteorites d. iron meteorites e. stony-iron meteorites
A
65. Which of the following likely helps replenish the zodiacal dust in the vicinity of Earth the most? a. comets b. asteroids c. the Moon d. volcanoes on Earth e. tornados on Earth
A
68. In 1994, dozens of fragments of Comet Shoemaker-Levy 9 collided with a. Jupiter. b. Earth. c. Neptune. d. the Moon. e. Saturn.
A
69. Consider a meteoroid with a diameter of 10 cm and a mass of 2 kg that hits Earth head-on while traveling at a speed of 25,000 m/s. How many times larger or smaller is the meteoroid's kinetic energy compared to that of a typical train whose mass is 2 × 106 kg and speed is 25 m/s? a. The meteoroid's kinetic energy is equal to that of the train. b. The meteoroid's kinetic energy is 1,000 times less than that of the train. c. The meteoroid's kinetic energy is 1,000 times greater than that of the train. d. The meteoroid's kinetic energy is 106 times greater than that of the train. e. The meteoroid's kinetic energy is 109 times greater than that of the train.
A
8. Currently the surface of the dwarf planet Eris is covered with _________, which makes it have the highest albedo of any object in the Solar System. a. methane ice b. water ice c. nitrogen ice d. sulfur dioxide ice e. carbon dioxide ice
A
10. The dwarf planet Eris has a moon called Dysnomia, which is much smaller in mass than Eris. If Dysnomia has an orbital period of 16 days and orbits Eris at a distance of 40,000 km, then what is the mass of Eris? a. 2 × 1013 kg b. 2 × 1022 kg c. 2 × 1028 kg d. 2 × 1032 kg e. 2 × 1035 kg
B
14. Meteorites are a. remnants of a single object near Pluto that never coalesced to form a planet. b. fragments of planetesimals between Mars and Jupiter. c. comets that formed close enough to the Sun to have lost all their volatiles. d. objects ejected from Saturn's rings.
B
17. Most asteroids are located between the orbits of a. Earth and Mars. b. Mars and Jupiter. c. Jupiter and Saturn. d. Neptune and Pluto. e. the Kuiper Belt and the Oort Cloud.
B
2. What group of solar system objects does Pluto belong to? a. the Trojan asteroids b. the dwarf planets c. the giant objects d. the terrestrial planets
B
20. Which group of asteroids regularly crosses Earth's orbit and thus might possibly collide with our planet? a. the Amors b. the Atens c. the Kuiper Belt objects d. the Trojans e. all of the above
B
25. Carbonaceous chondrite meteorites are fragments of which type of asteroid? a. A-type b. C-type c. M-type d. Q-type e. S-type
B
27. The most straightforward way to determine the mass of an asteroid is if it has a. a rocky composition. b. a moon. c. an orbit that lies between Earth and Mars. d. carbonaceous chondrites. e. a magnetic field.
B
28. In November 2005, the Japanese spacecraft Hayabusa brought back a sample from which type of object for the first time? a. comet b. asteroid c. moon d. terrestrial planet e. gas giant planet
B
31. Which type of comet is the most common? a. short-period comets b. long-period comets c. There are approximately equal numbers of both. d. Astronomers have no way of knowing this.
B
35. Most comets originate a. near Earth and Venus, in the early Solar System. b. far from the planets, many thousands of astronomical units (AU) from the Sun. c. from the region between the orbits of Jupiter and Neptune. d. between the Sun and Mercury. e. between the orbits of Mars and Jupiter.
B
46. Suppose we discover a comet whose orbit was very highly eccentric, retrograde, had a very large tilt with respect to the ecliptic plane, and a period of 2,000 years. Where is the most likely place of origin for this comet? a. the Kuiper Belt b. the Oort Cloud c. the asteroid belt d. the Jovian family e. outside the Solar System
B
49. Which type of meteorite is most commonly found on Earth? a. metallic b. stony c. glassy d. They are all equally common.
B
50. What implication does the composition of cometary nuclei have for the creation of life? a. They hold water, which is needed by all life. b. They hold organic compounds, evidence that the ingredients necessary for the creation of life were present in the early solar nebula. c. Bacteria have been found in cometary nuclei, proving that life on Earth came from comets. d. They hold oxygen, which is needed for all life.
B
52. The Perseid meteor shower will occur a. every month. b. every year. c. every 4 years. d. every 76 years. e. every 132 years.
B
53. The meteoroids in the Leonids meteor shower, which occurs every November, come from a. dust in the star-forming Leo nebula. b. dust melted off Comet Tempel-Tuttle. c. debris from the collision of Comet Shoemaker-Levy 9. d. zodiacal dust. e. dust blown off of Earth's surface.
B
54. The Lyrid meteor shower occurs every year on approximately April 21 because a. the Lyrae constellation is directly overhead at midnight. b. Earth passes through a cloud of debris left behind by Comet Thatcher. c. Earth passes through a cloud of debris left over from the Solar System's formation. d. Earth undergoes a periodic volcanic eruption every April. e. the Sun is located in the Lyrae constellation at noon.
B
56. Identify the phenomenon shown in the figure below. a. an active comet b. a meteor shower c. a meteorite d. an asteroid e. zodiacal dust
B
58. Antarctica is the best hunting ground for meteorites for all of the following reasons except a. the ground is covered with ice. b. more meteorites fall there than on other locations on Earth. c. few native rocks are found on the glaciers. d. meteorites are protected from weathering and contamination there. e. by searching at different depths in the ice you can determine the history of impacts over time.
B
59. Identify the object shown in the figure below. a. a meteor b. a chondrite meteorite c. an achondrite meteorite d. an iron meteorite e. an asteroid
B
6. Which of following is false? a. Pluto has five moons. b. Pluto has a mass that is 10 times less than Earth's mass. c. Pluto's orbit sometimes brings it closer to the Sun than Neptune. d. Pluto was discovered by Clyde Tombaugh in 1930. e. Pluto has a thin atmosphere.
B
66. All of the zodiacal dust in the Solar System combined is roughly equal in mass to a. a meteoroid. b. a comet. c. Jupiter. d. the Moon. e. a terrestrial planet.
B
7. Pluto has a density that is roughly equal to two times that of a. a feather. b. water. c. lead. d. a rock. e. air.
B
70. A recent estimate finds that approximately 800 meteorites with mass greater than 0.1 kg strike the surface of Earth each day. If a house covers an area of roughly 100 m2, then what is the probability that your house will be struck by a meteorite in your 100-year lifetime? Note that the radius of Earth is 6,400 km. a. 1 in 1 × 104 b. 1 in 2 × 105 c. 1 in 4 × 106 d. 1 in 6 × 107 e. 1 in 8 × 108
B
9. Eris, Ceres, and Haumea are examples of a. asteroids. b. dwarf planets. c. meteoroids. d. comets. e. meteor showers.
B
11. How does the mass of Pluto compare to that of Earth? a. It is around 100 times smaller. b. It is around 1000 times smaller. c. It is around 450 times smaller. d. It is around 10 times smaller.
C
15. Why do some short period comets have orbits within the orbit of Jupiter? a. They were created from the asteroid belt between Mars and Jupiter. b. They actually orbit Jupiter rather than the Sun. c. As they traveled to the inner Solar System from the Kuiper Belt, they suffered a gravitational encounter with Jupiter, which trapped them. d. As they traveled to the inner Solar System from the Kuiper Belt, they collided with one another and no longer had enough speed to reach the Kuiper Belt again.
C
16. The Kirkwood gaps are regularly spaced gaps in the asteroid distribution. What causes the gaps to appear? a. The pressure of the solar wind is especially strong at these locations, evacuating asteroids out of them. b. They are regions where gravitational pull from Mars is overcome by gravitational pull from Jupiter. c. They are regions where an object and Jupiter would regularly line up during their orbits, causing the object to repeatedly be tugged by Jupiter's gravity until it leaves that orbit. d. They are regions between Jupiter and Saturn where the combined effect of both planets' gravity prevents objects from orbiting there.
C
21. Asteroids are primarily composed of a. hydrogen and helium. b. ice and dust. c. rock. d. iron. e. methane.
C
23. The darkest asteroids are a. M-type. b. S-type. c. C-type. d. A-type. e. Q-type.
C
24. Iron meteorites are fragments of which type of asteroid? a. A-type b. C-type c. M-type d. Q-type e. S-type
C
26. Until spacecraft flew by asteroids, scientists did not have a good idea of what they looked like. Which of the following missions was the first to fly by an asteroid? a. NEAR Shoemaker b. Rosetta c. Galileo d. Dawn e. Stardust
C
29. Remnants of volcanic activity on the asteroid Vesta indicate that members of the asteroid belt a. were once part of a single protoplanet that was shattered by collisions. b. have all undergone significant chemical evolution since formation. c. occasionally grow large enough to become differentiated and geologically active. d. were once a part of a young Mars. e. used to be volcanic moons orbiting other planets.
C
3. Pluto is composed primarily of a. rock. b. ice. c. a rocky core surrounded by ice. d. metallic hydrogen.
C
37. Approximately how often does a spectacularly active, visible comet appear? a. once a year b. once every 5 years c. once every 10 years d. once every 50 years e. once every 1,000 years
C
4. Pluto has an atmosphere that comes and goes over an orbital period, because a. the atmosphere escapes into space because of the low escape velocity from Pluto. b. the atmosphere is pulled away from the planet by interaction with its moon Charon. c. the atmosphere "freezes out" when Pluto is at its farthest from the Sun. d. chemical reactions between Pluto's atmosphere and gas expelled by its many volcanoes generates carbon dioxide, which is too heavy to stay aloft in the atmosphere.
C
45. Comet nuclei, absent their tails, are very dark because a. they are made of water ice. b. they have iron and nickel mixed with ice. c. they have organic molecules mixed with ice. d. they are covered in rock. e. they are too cold to emit any light.
C
48. What is the main source of meteors? a. short-period comets b. long-period comets c. asteroids d. terrestrial planets
C
57. Meteor showers appear as if they are coming from one particular place in the sky because a. that is the direction in which the comet is coming toward us. b. that is the direction in which the comet is moving away from us. c. that is the direction toward which Earth is traveling. d. that is the direction Earth just passed. e. that is the location in the sky from which the meteors originate.
C
60. Meteorites contain clues to all of the following except a. the age of the Solar System. b. the temperature in the early solar nebula. c. changes in the rate of cratering in the early Solar System. d. the composition of the primitive Solar System. e. the physical processes that controlled the formation of the Solar System.
C
1. Which of the following types of solar system debris were not discovered until the age of tel-escopes? a. comets b. meteoroids c. zodiacal dust d. asteroids e. all of the above
D
12. Where are asteroids found? a. between Mars and Jupiter b. inside Earth's orbit, halfway to the Sun c. in the farthest reaches of the Solar System, beyond Pluto d. throughout the Solar System
D
13. When combined, asteroids have a mass equivalent to a. about 1/10th the mass of Earth's Moon. b. about equal to the mass of Earth's Moon. c. about 1/2 the mass of Earth's Moon. d. about 1/25th the mass of Earth's Moon.
D
32. How do astronomers identify the parent comet of a meteor observed in Earth's atmosphere? a. They use the brightness of the meteor. b. They accurately measure the time of the night when the meteor is seen. c. They measure how long a streak the meteor generates in the atmosphere. d. They use the speed and direction of a cometary meteor's flight to identify its parent comet.
D
41. The nuclei of a comet is mostly a. solid ice. b. solid rock. c. liquid water. d. a porous mix of ice and dust. e. frozen carbon dioxide.
D
42. When a comet comes close to the Sun, its volatile ice sublimates and transforms directly from the solid to _________ phase. a. liquid b. crystalline c. energized d. gas e. ionized
D
43. Why does the dust tail separate from the ion tail? a. The dust has no charge, so it is not affected by the solar wind. b. Dust cannot sublimate as ice can, so it cannot form a tail as easily. c. The dust tail forms on the leading side of the nucleus, whereas the gas tail forms on the opposite side. d. Dust particles are more massive than ions, so their accelerations are less. e. The dust tail has the opposite charge as the ion tail.
D
63. Although most meteorites have ages around 4.5 billion years, a small subset has ages around 1.3 billion years. What caused the substantial difference in age between these two populations of meteorites? a. These meteorites just happened to form later than most meteorites. b. Not all meteorites hit Earth in the early Solar System. We should expect to find younger meteorites as more meteors pass through the atmosphere. c. The younger meteorites were created when a protoplanet collided with Earth, creating the Moon. The leftover fragments became meteorites. d. These meteorites were thrown into space after an impact with Mars and afterward some happened to collide with Earth. e. The younger ones are the result of comets repeatedly passing close to the Sun, melting their surfaces and making them appear younger.
D
67. In the early universe, when the Solar System had yet to be cleared of the debris out of which it formed, which type of object would have been most likely to deposit water onto Earth's surface? a. comets b. asteroids c. a Mars-sized protoplanet d. Both comets and asteroids appear to be sources. e. None, because water is not a major component of any of the objects above.
D
18. Most asteroids are a. very large (>100 km). b. large (30−100 km). c. medium (10−30 km). d. small (1−10 km). e. very small (<1 km).
E
19. The mass of all the known asteroids combined is approximately equal to a. half the mass of Earth. b. three times the mass of Earth. c. twice the mass of Mars. d. the mass of Mars. e. less than one-third the mass of the Moon.
E
34. A comet having an orbit of 50 years would likely have come from the a. Atens family. b. Oort Cloud. c. Trojan family. d. zodiacal zone. e. Kuiper Belt.
E
36. The one orbital characteristic that both short- and long-period comets share is a. mostly prograde orbits. b. orbits with completely random tilts. c. mostly retrograde orbits. d. orbital periods longer than any planet. e. highly eccentric orbits.
E
39. With a semimajor axis of 18 AU, Comet Halley has a period of a. 7 years. b. 16 years. c. 32 years. d. 67 years. e. 76 years.
E
47. Which of the following does not describe comets in the Oort Cloud? a. long period b. pristine condition c. cold temperatures d. randomly directed orbits e. flattened distribution in space
E
51. The minimum size of a meteoroid that is capable of surviving its passage through Earth's atmosphere and hitting the ground is about as big as a. a car. b. a house. c. a basketball. d. a grain of sand. e. your fist.
E
55. A large meteor shower will often occur once a year because a. Earth typically has one large volcanic eruption every year. b. Earth's orbit passes through the Apollo asteroid belt. c. the Sun goes through a yearly solar cycle. d. Jupiter routinely disturbs the orbits of asteroids in the Jovian belt. e. Earth passes through the debris left behind by a specific comet.
E
64. Identify the object shown in the image below. a. an active comet b. a meteor shower c. a meteorite d. an asteroid e. zodiacal dust
E
44. Which of the following comets has not been visited by spacecraft? a. Halley b. Wild 2 c. Tempel 1 d. Hartley 2 e. Shoemaker-Levy 9
E DIF: Easy REF: Section 12.3 MSC: Remembering
