1. LECTURE 23, NOVEMBER 23, 2010 ASTR 101, SECTION 3 INSTRUCTOR, JACK BRANDT jcbrandt@unm.edu 1ASTR 101-3, FALL 2010

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5. a) makes up about 90 percent of the matter in the universe. b) is best detected by the largest optical telescopes. c) makes up about 10 percent of the matter in clusters of galaxies. d) exists but has no observable effects on galaxies. e) is the result of gas and dust. Question 1 Based on galactic rotation curves and motions in clusters of galaxies, dark matter

6. a) makes up about 90 percent of the matter in the universe. b) is best detected by the largest optical telescopes. c) makes up about 10 percent of the matter in clusters of galaxies. d) exists but has no observable effects on galaxies. e) is the result of gas and dust. Question 1 Based on galactic rotation curves and motions in clusters of galaxies, dark matter

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15. a) as it was when the universe was 1 billion years old. b) as it will be 1 billion years from now. c) as it was 1 billion years ago. d) as it is today, but redshifted 10 percent of the speed of light. e) as it was just after the Big Bang. Question 6 A galaxy seen 1 billion light-years away means we see it

16. a) as it was when the universe was 1 billion years old. b) as it will be 1 billion years from now. c) as it was 1 billion years ago. d) as it is today, but redshifted 10 percent of the speed of light. e) as it was just after the Big Bang. Question 6 A galaxy seen 1 billion light-years away means we see it Looking farther away in space means looking back further in time, to when the object (and universe) was younger.

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18. a) are much rarer than collisions between stars. b) can transform elliptical galaxies into spirals. c) trigger Type II supernova explosions in the halo. d) cause gas and dust clouds to collide, leading to rapid star formation. Question 2 Collisions between galaxies

19. a) are much rarer than collisions between stars. b) can transform elliptical galaxies into spirals. c) trigger Type II supernova explosions in the halo. d) cause gas and dust clouds to collide, leading to rapid star formation. Question 2 Collisions between galaxies Galaxies are relatively close compared with their size. In clusters of galaxies, collisions clearly occur.

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21. a) the source of energy is very small. b) energy is coming from matter and antimatter. c) the energy source is rotating rapidly. d) a chain reaction of supernovas occurs. e) there are many separate sources of energy in the core. Question 5 The rapid variation of brightness of quasars indicates

22. a) the source of energy is very small. b) energy is coming from matter and antimatter. c) the energy source is rotating rapidly. d) a chain reaction of supernovas occurs. e) there are many separate sources of energy in the core. Question 5 The rapid variation of brightness of quasars indicates The size of an object cannot be larger than the distance light can travel in the time it takes to change its brightness.

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29. a) a smooth, continuous, and homogeneous arrangement of clusters. b) large voids, with most of the galaxies lying in filaments and sheets. c) a large supercluster at the center of the universe. d) a central void with walls of galaxies at the edge of the universe. Question 7 The large-scale distribution of galaxies in the universe reveals

30. a) a smooth, continuous, and homogeneous arrangement of clusters. b) large voids, with most of the galaxies lying in filaments and sheets. c) a large supercluster at the center of the universe. d) a central void with walls of galaxies at the edge of the universe. Question 7 The large-scale distribution of galaxies in the universe reveals

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