Full Test Bank Chapter 9 Small Bodies of the Solar System

Chapter 9: Small Bodies of the Solar System

LEARNING OBJECTIVES

9.1 Dwarf Planets May Outnumber Planets

9.1a Distinguish the characteristics of a dwarf planet from those of a planet.

9.1b Name the known dwarf planets.

9.2 Moons as Small Worlds

9.2a List the four states of geological activity of a moon.

9.2b Summarize the observations or characteristics that differentiate between moons with current geological activity, possible activity, past activity, and no activity.

9.2c Explain how moons can be geologically active today, whereas comparably sized planets are geologically dead.

9.3 Asteroids Are Pieces of the Past

9.3a Differentiate an asteroid from a dwarf planet.

9.3b Explain why asteroids are an ancient and pristine record of the early Solar System.

9.4 Comets Are Clumps of Ice

9.4a Describe the two homes of comets.

9.4b Describe the four parts of an active comet and how we study them.

9.4c Describe the changes in a comet’s appearance over the course of its orbit.

9.5 Comet and Asteroid Collisions Still Happen Today

9.5a Summarize why it is important to search for and characterize all near-Earth objects.

9.6 Meteorites Are Remnants of the Early Solar System

9.6a Differentiate among meteors, meteorites, and meteoroids.

9.6b Describe how the meteors in a shower all appear to come from the same point on the sky.

9.6c Explain how meteorites provide critical clues to the origin and history of our Solar System.

Working It Out 9.1

Working It Out 9.1a Use kinetic energy and density to find the radius of a meteoroid.

Chapter 9: Small Bodies of the Solar System

MULTIPLE CHOICE

1. Eris and Ceres are examples of

a. asteroids. c. comets.

b. dwarf planets. d. meteor showers.

2. Which of the following is true?

a. Pluto has no moons.

b. Pluto has a mass that is one-tenth of Earth’s mass.

c. Pluto’s orbit sometimes brings it closer to the Sun than Neptune.

d. Pluto has yet to be visited by a space probe.

3. Which dwarf planet is depicted here?

a. Pluto c. Makemake

b. Dysnomia d. Haumea

4. Examine the following image. What does the pale heart-shaped region toward the lower right tell astronomers?

a. The surface is ancient.

b. A large impact must have recently occurred.

c. Tidal forces are at work.

d. The interior must have been hot in the recent past.

5. Which of the following is true about dwarf planets?

a. Only a few are expected to be in our solar system.

b. They have cleared out their orbits.

c. They’re generally round.

d. They all have moons.

6. Which dwarf planet is found in the asteroid belt?

a. Pluto c. Makemake

b. Ceres d. Haumea

7. The following image was taken by the Dawn spacecraft showing bright spots inside a crater. What dwarf planet is this?

a. Pluto c. Eris

b. Makemake d. Ceres

8. The surface of the dwarf planet Eris has very high albedo and is covered with

a. methane ice. c. sulfur dioxide.

b. water ice. d. frozen carbon dioxide.

9. What is the most common geological feature seen on moons?

a. craters c. palimpsests

b. volcanoes d. geysers

10. Which of the following is now geologically inactive?

a. Ganymede c. Enceladus

b. Triton d. Io

11. Which object has turned its mantle inside out numerous times, leading to lighter elements escaping, sulfur compounds composing the crust, and heavier elements making up the core?

a. Mercury c. Pluto

b. Titan d. Io

12. How do particles from Enceladus wind up in Saturn’s E Ring?

a. Volcanoes erupt and expel silicates into space.

b. Water geysers erupt from the surface and expel particles into space.

c. Cosmic rays bombard the surface rock on Enceladus and expel particles into space.

d. A collision with a co-orbiting moon knocked rocky debris into orbit around Saturn.

13. What is unusual about Saturn’s moon Mimas?

a. It has a similar size and orbit as Enceladus but is geologically dead.

b. It’s the only moon with an atmosphere.

c. It has no craters.

d. It’s one of only two moons larger than Mercury.

14. Which of the following moons is thought to have a vast ocean of water beneath its thin frozen surface?

a. Titan c. Io

b. Europa d. Callisto

15. Titan’s thick atmosphere (see the following image) is hypothesized to have been created when ultraviolet photons broke apart methane molecules, ultimately creating the observed smoglike conditions. This process, though, would likely remove all of the atmospheric methane in roughly 50 million years, yet we still see its presence today. How can this be?

a. Cometary impacts periodically bring new methane to Titan.

b. Ethane rains down out of the atmosphere, combines with surface rocks, and creates new methane.

c. Infrared photons give atmospheric molecules enough energy to recombine into methane.

d. Cryovolcanism on Titan must release new methane into the atmosphere.

16. What are the possible geological states of a moon?

a. active today and active in the past

b. possibly active today

c. never active

d. active today; possibly active today; active in the past; never active

17. What might cause a moon to be geologically active, whereas its planet is not?

a. The moon may contain more magnetic material than the planet.

b. The moon’s rotation is tidally locked to the planet.

c. Heating of the moon by its planet’s heat of formation may cause it to be active.

d. The moon orbital distance from the planet and/or other moons may cause tidal stresses that can heat its interior.

18. Which of the following can be used as an indicator of the age of a moon’s surface?

a. surface brightness c. volcanic activity

b. crater density d. all of the above

19. The varied colors found on Io’s surface are due to the presence of various molecules containing

a. sulfur. c. mercury.

b. silicon. d. magnesium.

20. Which moon is a good example of one that has never been active since formation?

a. Ganymede c. Triton

b. Callisto d. Titan

21. Which is the largest moon in the solar system?

a. Earth’s Moon c. Ganymede

b. Callisto d. Titan

22. How can moons be more geologically active than planets?

a. Some moons have magnetic fields that are stronger than planets.

b. Some moons have a faster rotation rate than some planets.

c. The tidal stresses experienced by some moons can heat the interior.

d. Moons that are denser than the planets they orbit attract more colliding objects.

23. Which property of a moon would classify it as irregular?

a. It is tidally locked.

b. Its orbital axis is tilted little compared with the planet’s rotational axis.

c. It revolves around the planet opposite the planet’s spin direction.

d. Its orbit is circular.

24. Which moon gives rise to the particles that make up Saturn’s E Ring?

a. Titan c. Enceladus

b. Triton d. Tethys

25. Where does Titan’s thick atmosphere (see the following image) come from?

a. photodissociation of methane in its atmosphere

b. geologic activity

c. cometary impacts over the age of the Solar System

d. photosynthesis of algae in oceans that lie beneath its icy surface

26. Most asteroids are closest in shape to

a. an Idaho potato. c. a stick.

b. an orange. d. a baseball.

27. The mass of all the known asteroids combined would be as much as

a. half the mass of Earth. c. the mass of Mars.

b. three times the mass of Earth. d. one-third the mass of the Moon.

28. Which of the following does NOT describe comets in the Oort Cloud?

a. long period c. randomly directed orbits

b. pristine condition d. flattened distribution

29. Comet nuclei, like those far from the sun and absent 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.

30. When a comet comes close to the Sun, its volatile ice sublimates and transforms directly from the solid to __________ phase.

a. liquid c. gas

b. crystalline d. ionized

31. Suppose we discover a comet whose orbit was very highly eccentric, was retrograde, had a very large tilt with respect to the ecliptic plane, and had a period of 2,000 years. Where is the most likely place of origin for this comet?

a. the Kuiper Belt c. the giant planet family

b. the Oort Cloud d. outside the Solar System

32. Most comets originate

a. near Earth and Venus in the early Solar System.

b. far from the planets, many thousands of astronomical units from the Sun.

c. from the region between the orbits of Jupiter and Neptune.

d. between the Sun and Mercury.

33. The likely source of comets that mostly have orbits of extreme tilt with respect to the ecliptic is the

a. Kuiper Belt. c. asteroid belt.

b. Oort Cloud. d. rings of Saturn.

34. Why does the dust tail separate from the ion tail?

a. The dust is not ionized, 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 is more massive than ions, so it accelerates less.

35. The nucleus of the typical comet is approximately __________ in size.

a. 10 kilometers (km) c. 10 meters

b. 1,000 km d. 1 cm

36. Which of the following is the BRIGHTEST part of a comet?

a. nucleus c. ion tail

b. coma d. dust tail

37. A comet having an orbit of 50 years would likely have come from the

a. Trojan family c. zodiacal zone

b. Oort Cloud d. Kuiper Belt

38. The one orbital characteristic both short- and long-period comets share is

a. mostly prograde orbits.

b. orbits with completely random tilts.

c. orbital periods longer than that of any planet.

d. highly eccentric orbits.

39. Which spacecraft landed on a comet?

a. Huygens c. Giotto

b. Deep Impact d. Philae

40. Cometary nuclei are most likely

a. solid ice. c. porous.

b. rocky. d. uniform.

41. In 1994, dozens of fragments of Comet Shoemaker-Levy 9 collided with

a. Jupiter. c. the Moon.

b. Earth. d. Saturn.

42. The most common type of meteorite is

a. stony meteorite. c. stony-iron meteorite.

b. iron meteorite. d. carbonaceous chondrite meteorite.

43. The chronological description of an asteroidal fragment that falls to Earth would be

a. meteor, meteorite, meteoroid. c. meteoroid, meteor, meteorite.

b. meteorite, meteoroid, meteor. d. meteor, meteoroid, meteorite.

44. The radiant of a meteor shower is the

a. apparent vanishing point of the parallel paths of meteors.

b. location at which a meteor explodes in the atmosphere.

c. radius of a meteoroid’s orbit around the Sun.

d. radius of a meteoroid’s orbit around the Earth.

45. Meteorites contain clues to which of the following?

a. the age of the Solar System.

b. the temperature in the early solar nebula.

c. the composition of the primitive Solar System.

d. All choices are valid.

46. Where is the best hunting ground for meteorites?

a. The Arctic c. Ocean floors

b. Antarctica d. Any of the major continents

47. 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. c. a grain of sand.

b. a house. d. your fist.

48. The type of meteorites most likely to have originated from the outer layers of differentiated planetesimals come from

a. comets. c. M-type asteroids.

b. C-type asteroids. d. S-type asteroids.

49. Which group of meteoroids is more likely to have compositions indicative of those in the early Solar System?

a. asteroidal meteoroids

b. cometary meteoroids

c. cometary and some asteroidal meteoroids

d. neither group (All meteoroids have undergone significant chemical evolution.)

50. Which group of meteorites represents the conditions in the earliest stages of the formation of the Solar System?

a. chondrites c. iron meteorites

b. achondrites d. stony-iron meteorites

51. The darkest asteroids are

a. M-type. c. C-type.

b. S-type. d. Q-type.

1. Name three properties of the dwarf planets Pluto and Eris that are similar.

2. Explain why many of the 100 known objects in the Kuiper Belt have not been designated as dwarf planets.

3. What are the two basic materials of which the moons in the Solar System are composed? For each type of material, name an example of a moon whose surface is composed primarily of that material.

4. Why is Io, a moon that is smaller and farther from the Sun than our own Moon, still geologically active?

5. Europa is a very interesting moon that NASA is considering visiting with a spacecraft to search for signs of life. What is it about this moon that makes it so interesting, and what surface features give us clues about its interior?

6. If ultraviolet photons destroy methane, why does Titan have so much of it in its atmosphere?

7. Ganymede is one of the largest moons in the Solar System. It shows some terrain that is ancient and heavily cratered, younger terrain with less craters, but no terrain that is free of craters. Why would Ganymede’s geological activity stop?

8. What material has been seen erupting from the surface (see the following image) of the icy moon Enceladus, and why?

9. Two moons are observed to each have a large amount of cratering over their surfaces. However, one of the moons has portions of its surface that are darker than other portions. What might this suggest regarding the state of geologic activity of these moons?

10. Phobos and Deimos, the two moons of Mars, are thought to have a unique origin. What is it?

11. Why is the asteroid Ceres classified as a dwarf planet?

12. Why do long-period comets usually put on a much more visually spectacular display than short-period comets?

13. In the following figure, label each portion of the comet.

14. Why are cometary dust tails curved along the orbit of a comet?

15. Examine the following figure. How is it possible for the tails of a comet to move ahead of the comet itself?

16. Consider three comets that have orbital periods of 10, 100, and 1,000 years. Where would each of these comets likely originate, in the Oort Cloud or the Kuiper Belt? If you wanted to study material that was the best example of pristine Solar System material, which would you study?

17. Examine the following image. Why does a comet usually have two tails, one that is straight and one that is curved? What materials compose each tail, and why do they have different shapes?

18. Describe two modern-day events when comets or asteroids collided with a planet. Cite the planet, give the approximate year when the collision occurred, and describe the major consequences of the collision.

19. A rocky meteoroid explodes over earth with a shock wave energy of 10¹⁵ joules. If it was moving at a velocity of 19 kilometers per second (km/s), determine its mass. What is the radius of this meteoroid if its density is 2,500 kilograms per cubic meter (kg/m³) and it is spherical (volume )?

20. What does the existence of M-type asteroids tell us about their origin?

21. Give the definitions of meteoroid, meteor, and meteorite, and clearly explain how they differ.

22. You find a blackened rock lying on top of the snow. You discover that it is fairly dense and suspect it might be a meteorite. You take it to a lab, and they find that its age is 1.3 billion years. Is this a meteorite? Why, or why not?