Formation of Structure Test Bank Palen Ch.17 - Understanding Our Universe 3e Complete Test Bank by Stacy Palen. DOCX document preview.
Chapter 17: Formation of Structure
LEARNING OBJECTIVES
17.1 Galaxies Form Groups, Clusters, and Larger Structures
17.1a Compare and contrast groups, clusters, superclusters, and walls.
17.1b Describe the observational components of galaxy structures.
17.1c Explain how soap bubbles are and are not an appropriate description of large-scale structure.
17.2 Gravity Forms Large-Scale Structure
17.2a Describe how gravitational instabilities created the seeds of large-scale structure.
17.2b Summarize the observational evidence that dark matter cannot be composed of ordinary matter.
17.2c Relate primordial helium and deuterium abundance to the density of matter in the universe today.
17.2d Compare and contrast the properties and possible constituents of cold and hot dark matter.
17.2e Describe the collapse of cold dark matter into a galaxy halo after recombination.
17.3 The First Stars and Galaxies Form
17.3a Describe the properties of the first generation of galaxies and whether these are based on observations or hypotheses.
17.3b Compare and contrast the processes of star and galaxy formation.
17.4 Galaxies Evolve
17.4a Describe the hierarchical formation scenario in which fragments built up into today’s galaxies.
17.4b Summarize the observational evidence that galaxies formed by hierarchical merging.
17.5 Astronomers Think about the Deep Future
17.5a Describe the expected stages of future evolution of our universe.
Working It Out 17.1
Working It Out 17.1a Determine the mass of a cluster of galaxies.
Chapter 17: Formation of Structure
MULTIPLE CHOICE
1. Which of the following structures is the largest?
a. globular cluster c. galaxy group
b. galaxy cluster d. supercluster
2. Our Milky Way Galaxy is a member of
a. the Local Group. c. Laniakea Supercluster.
b. the Virgo Supercluster. d. All choices are valid.
3. What does the large-scale structure of the universe look most like?
a. a sponge with many large holes
b. a loaf of wheat bread with many tiny holes
c. a plate of flat noodles
d. a jar of marbles
4. Galaxy clusters have been observed to be rich in hot, X-ray–emitting gas. What contributes in keeping the gas in the cluster?
a. dark matter c. the speed of the hot gas
b. the gravitational pull of the galaxies d. All of the choices contribute.
5. The patterns of walls and voids that are observed
a. only occur in the Virgo Cluster. c. support the cosmological principle.
b. are optical illusions. d. are made of dark matter.
6. What is the method used to measure the distances to the farthest galaxies when mapping out large-scale structures?
a. Cepheid variables c. redshifts and Hubble’s law
b. parallax d. RR Lyrae variables
7. What is the name of the region depicted here along with its collection of galaxies?
a. Virgo Cluster c. Local Group
b. Coma Cluster d. Laniakea Supercluster
8. What is the diameter of the region depicted here with this collection of galaxies?
a. 2 megaparsecs (Mpc) c. 100 Mpc
b. 30 Mpc d. 159 Mpc
9. Where is the bulk of the mass concentrated in the region depicted here?
a. space between the galaxies c. collection of dwarf galaxies
b. two main spiral galaxies d. The mass is evenly distributed.
10. What type of galaxy is most numerous in the region depicted here?
a. spirals c. ellipticals
b. barred spirals d. dwarf galaxies
11. What distinguishes galaxy groups from galaxy clusters?
a. their volume c. the total mass of galaxies
b. the number of galaxies d. All choices apply.
12. What process causes the arc of light in the zoomed-in section of the following image?
a. emissions from intergalactic trails of hot gas
b. emissions from jets of active galactic nuclei (AGNs)
c. colliding galaxies
d. gravitational lensing of background galaxies
13. Astronomers use the arcs in the zoomed-in section of the following image to
a. trace the distribution of dark matter in the cluster.
b. determine the distance of the cluster.
c. determine the size of the cluster.
d. determine the age of the cluster.
14. Examine the following redshift survey. What is true about voids?
a. They are some of the largest structures in the universe.
b. They are surrounded by walls.
c. They contain very few observable galaxies.
d. All choices are valid.
15. Examine the following redshift survey. What is true about walls?
a. They contain clusters and superclusters.
b. They are linked by filaments.
c. They surround large areas that look empty.
d. All choices are valid.
16. What process is most responsible for shaping the large-scale structure of the universe?
a. supernovae from the first generation of stars
b. gravity
c. matter/antimatter annihilation
d. magnetic fields
17. If the quantum fluctuations imprinted on the dark matter halos at the time of the formation of the cosmic microwave background radiation were 10 times larger, galaxies would likely be
a. smaller. c. more numerous.
b. larger. d. nonexistent.
18. Our current ideas on galaxy formation suggest that the visible parts of galaxies
a. form first and are incorporated into dark matter halos later.
b. form only in the densest parts of dark matter halos.
c. can tell you the total size of the dark matter halo.
d. can tell you everything about the formation history of that galaxy.
19. Why can’t dark matter halos collapse to be the same size as the visible parts of galaxies? Dark matter
a. can’t dissipate its energy through radiation.
b. is mostly made of mini black holes.
c. has much more angular momentum.
d. annihilates when it begins to get that dense.
20. The earliest isotopes of low-mass nuclei (deuterium, helium, lithium, beryllium, boron) were formed in a process called
a. Big Bang nucleosynthesis. c. nuclear fusion.
b. nuclear fission. d. stellar nucleosynthesis.
21. Axions and photinos are expected to be examples of
a. cold dark matter. c. neutrinos.
b. hot dark matter. d. normal matter.
22. Which of the following are expected to make up a significant amount of hot dark matter?
a. axions c. photinos
b. neutrinos d. photons
23. Which of the following provided the gravity to form galaxy fragments in the early universe?
a. cold dark matter halos c. hot dark matter halos
b. galaxy clusters d. large clouds of gas and dust
24. Which of the following may be dark matter?
a. axions c. photinos
b. neutrinos d. All are valid choices.
25. If neutrinos have mass but do not interact much with normal matter, why can’t they be the dominant form of dark matter in the universe?
a. Structure formation requires some sort of cold dark matter to clump under gravity, and fast-moving neutrinos are not easily bound to matter.
b. Structure formation would have started with small objects merging to form larger objects.
c. Neutrinos would decay over time and disappear, causing galaxies to fall apart.
d. Neutrinos would not gravitationally lens background galaxies.
26. The observed abundances of helium and deuterium in the universe
a. support models of Big Bang nucleosynthesis.
b. disprove the Big Bang model of the universe.
c. do not match predictions.
d. contradict the density of matter observed in the universe.
27. Astronomers measuring the amount of normal matter in the universe found that it matches the amount predicted by Big Bang. What is the importance of this finding?
a. Dark matter cannot be made up primarily of normal matter, such as protons and neutrons.
b. Dark matter is made up primarily of normal matter, such as protons and neutrons.
c. There is no need to require dark matter in our understanding of the large-scale structure of the universe.
d. Dark matter is made up primarily of neutrinos.
28. How much of the total mass of the universe is made up of hot dark matter?
a. 5 percent c. 45 percent
b. 25 percent d. 90 percent
29. Suppose we observe two clusters of galaxies, cluster A and cluster B, which are the same size. We then observe that the outer galaxies of cluster A orbit the cluster’s center with velocities that are twice that of the outer galaxies of cluster B. What can be said of the total mass of cluster A?
a. twice that of cluster B c. half that of cluster B
b. four times that of cluster B d. one-fourth that of cluster B
30. Suppose we observe outer galaxies with orbital velocities of 1 million meters per second (m/s) at a radial distance of 6 Mpc from the cluster’s center. Given that the universal gravitational constant G 
6.673 
10
m3/(kg s2) and 1 pc 3.09 1016 m, what is the total mass of this cluster?
a. 1.0 1045 kilograms (kg) c. 2.8 1045 kg
b. 1.4 1045 kg d. 6.0 1045 kg
31. Stars of the first generation were
a. less massive than today’s average star. c. similar to today’s average star.
b. more massive than today’s average star. d. We have no ability to predict.
32. The first generation of stars most likely formed __________ when the stars died.
a. black holes c. novae
b. neutron stars d. white dwarfs
33. What is one similarity between star formation and galaxy formation? Both processes
a. are dominated by gravity.
b. are still occurring at the same rate as in the first billion years of the universe.
c. only occurred in the early stages of the universe.
d. require dark matter.
34. The fact that we do not observe any stars with chemical compositions matching our predictions for the very first generation of stars implies that
a. our ideas of what the first stars were like are incorrect.
b. our technology is not sensative enough to detect the light of the first stars.
c. the first stars died quickly, which implies a high mass.
d. the first stars died quickly, which implies a low mass.
35. The first galaxies formed
a. because of merging black holes.
b. from merging clouds of gas.
c. out of large spinning clouds of gas and dust, collapsing under their own gravity.
d. within dark matter halos.
36. Structure formation in the universe proceeds hierarchically, meaning that
a. large objects collapse, then fragment to form smaller objects.
b. large objects form at the same times as smaller objects.
c. small objects collapse, then merge to form larger objects.
d. only small objects form and are stable over time.
37. We expect the kinds of galaxies that we see at a redshift of 4 (that is, when the universe was much younger) to be
a. much like what we see today.
b. smaller and much more irregular looking than today.
c. smaller versions of what we see today.
d. far more numerous but with fewer spiral galaxies.
38. Structure formation in our universe
a. proceeds from the top down.
b. proceeds from the bottom and moves up.
c. begins on all spatial scales at the same time.
d. begins after clusters form.
39. Which part of our Milky Way Galaxy has the youngest stars?
a. bulge
b. disk
c. halo
d. We cannot measure the relative ages of these structures.
40. Which part of our Milky Way Galaxy is the oldest?
a. bulge
b. disk
c. halo
d. We cannot measure the relative ages of these structures.
41. What is the evidence that galaxies can merge?
a. Galaxies at higher redshifts are smaller and more irregularly shaped.
b. The Hubble Space Telescope has observations of merging galaxies.
c. Simulations show that mergers produce observed galaxy shapes.
d. all of the above
42. Galaxies in clusters far from our Milky Way Galaxy appear
a. much like what we see in nearby clusters.
b. smaller and much more irregular looking than nearby galaxies.
c. smaller versions of what we see in nearby clusters.
d. far more numerous but with fewer spiral galaxies.
43. We expect the galaxies that we see at a redshift of 4 (that is, when the universe was much younger) will be intrinsically __________ than galaxies today.
a. more irregular and redder c. smaller and bluer
b. larger and redder d. smaller and redder
44. What do astronomers think will be the final state of our universe?
a. a “Big Crunch” in which everything collapses back in on itself
b. an ever-expanding universe filled with nothing but hydrogen and helium gas
c. a universe that stops expanding and is filled with nothing but white dwarfs, neutron stars, and black holes
d. an ever-expanding universe filled with photons and elementary particles
45. We currently live in the universe during its
a. era of stars. c. era of black holes.
b. era of degeneracy. d. era of darkness.
46. Which of the following statements is correct?
a. Stars evolve. c. The universe evolves.
b. Galaxies evolve. d. all of the above
47. During which era will the final black holes decay?
a. Dark Era c. Stelliferous Era
b. Black Hole Era d. Primordial Era
48. Which era corresponds to the final stage of the universe?
a. Dark Era c. Stelliferous Era
b. Degenerate Era d. Primordial Era
49. In order from first to last, the specific eras in the universe’s history are known as the
a. Primordial, Stelliferous, Degenerate, and Dark eras.
b. Stelliferous, Black Hole, and Entropy eras.
c. Primordial, Stelliferous, Black Hole, and Entropy eras.
d. Primordial, Stelliferous, Degenerate, Black Hole, and Dark eras.
50. During which era will the last star form?
a. Dark Era c. Stelliferous Era
b. Degenerate Era d. Primordial Era
1. Describe the large-scale structure of the universe.
2. Rank from smallest to largest: galaxy cluster, galaxy group, galaxy supercluster.
3. What is the name of the region displayed here?
4. What is the diameter of the region displayed here?
5. Describe what is causing the arcs seen in the following image.
6. Describe what can be learned from studying the arcs seen in the following image.
7. Describe what information is needed to determine the mass of a galaxy cluster given the relation
8. Calculate the mass of a galaxy cluster given that a galaxy is orbiting the cluster’s center at 1,000 km/s at a radial distance of 9.3 1022 meters.
9. What is the observational evidence that gravitational instabilities created the seeds of large-scale structure in the universe?
10. What is a photino?
11. What is an axion?
12. Characterize hot dark matter and give an example.
13. Explain why cold dark matter is essential to forming galaxies.
14. How do astronomers explain the role of mergers in the formation of elliptical galaxies?
15. The very first generation of stars has never been observed. Explain what this implies about the properties of these stars.
16. Evaluate some of the difficulties in modeling the evolution of galaxies.
17. Describe how elliptical galaxies form.
18. What is the evidence that galaxies form via hierarchical merging?
19. Put the following eras in the history of the evolution of the universe in their proper order from the earliest to the latest: Black Hole Era, Dark Era, Degenerate Era, Primordial Era, Stelliferous Era.
20. Astronomers currently think that the last stage of the universe will be the Dark Era. Explain what that implies for the future of the universe.