Astronomy A BEGINNER’S GUIDE TO THE UNIVERSE EIGHTH EDITION CHAPTER 16 Galaxies and Dark Matter Clickers © 2017 Pearson Education, Inc Question Based on galactic rotation curves and motions in clusters of galaxies, dark matter 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) © 2017 Pearson Education, Inc is the result of gas and dust Question Based on galactic rotation curves and motions in clusters of galaxies, dark matter 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) © 2017 Pearson Education, Inc is the result of gas and dust Question Collisions between galaxies a) b) c) d) are much rarer than collisions between stars can transform elliptical galaxies into spirals trigger Type II supernova explosions in the halo cause gas and dust clouds to collide, leading to rapid star formation © 2017 Pearson Education, Inc Question Collisions between galaxies a) b) c) d) are much rarer than collisions between stars can transform elliptical galaxies into spirals trigger Type II supernova explosions in the halo cause gas and dust clouds to collide, leading to rapid star formation Explanation: Galaxies are relatively close compared with their size In clusters of galaxies, collisions clearly occur © 2017 Pearson Education, Inc Question When spiral galaxies collide, the greatest impact occurs on their a) b) c) d) e) © 2017 Pearson Education, Inc globular cluster stars giant molecular clouds central bulge stars open clusters disk stars Question When spiral galaxies collide, the greatest impact occurs on their a) b) c) d) e) © 2017 Pearson Education, Inc globular cluster stars giant molecular clouds central bulge stars open clusters disk stars Question Due to the density and collisions among galaxies, _ are rare in the centers of clusters a) b) c) d) e) © 2017 Pearson Education, Inc giant ellipticals irregulars spirals active galaxies radio galaxies Question Due to the density and collisions among galaxies, _ are rare in the centers of clusters a) b) c) d) e) giant ellipticals irregulars spirals active galaxies radio galaxies Explanation: The gas, dust, and disks of spiral galaxies are tidally disrupted, and even destroyed, in the centers of dense clusters, which are often dominated by giant elliptical galaxies © 2017 Pearson Education, Inc Question The rapid variation of brightness of quasars indicates a) b) c) d) e) © 2017 Pearson Education, Inc the source of energy is very small energy is coming from matter and antimatter the energy source is rotating rapidly a chain reaction of supernovas occurs there are many separate sources of energy in the core Question The rapid variation of brightness of quasars indicates a) b) c) d) e) the source of energy is very small energy is coming from matter and antimatter the energy source is rotating rapidly a chain reaction of supernovas occurs there are many separate sources of energy in the core Explanation: The size of an object cannot be larger than the distance light can travel in the time it takes to change its brightness © 2017 Pearson Education, Inc Question A galaxy seen billion light-years away means we see it as it a) b) c) d) e) © 2017 Pearson Education, Inc was when the universe was billion years old will be billion years from now was billion years ago is today, but redshifted 10 percent of the speed of light was just after the Big Bang Question A galaxy seen billion light-years away means we see it as it a) b) c) d) was when the universe was billion years old will be billion years from now was billion years ago is today, but redshifted 10 percent of the speed of light e) was just after the Big Bang Explanation: Looking farther away in space means looking back further in time, to when the object (and universe) was younger © 2017 Pearson Education, Inc Question The large-scale distribution of galaxies in the universe reveals a) a smooth, continuous, and homogeneous arrangement of clusters b) large voids, with most of the galaxies lying in filaments and sheets c) d) a large supercluster at the center of the universe a central void with walls of galaxies at the edge of the universe © 2017 Pearson Education, Inc Question The large-scale distribution of galaxies in the universe reveals 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 © 2017 Pearson Education, Inc Question The lensing of a distant quasar is produced in a foreground galaxy by its a) b) c) d) e) © 2017 Pearson Education, Inc total mass of stars, gas, and dark matter central supermassive black hole globular clusters magnetic fields intergalactic gas Question The lensing of a distant quasar is produced in a foreground galaxy by its a) b) c) d) e) total mass of stars, gas, and dark matter central supermassive black hole globular clusters magnetic fields intergalactic gas Explanation: The twin quasar AC114 has two images of the same object © 2017 Pearson Education, Inc Question The blue arcs in this image are a) b) c) d) emission nebulae nearby blue dwarf galaxies blue supergiant stars a very distant galaxy imaged by a massive galaxy cluster between us and the distant galaxy © 2017 Pearson Education, Inc Question The blue arcs in this image are a) b) c) d) emission nebulae nearby blue dwarf galaxies blue supergiant stars a very distant galaxy imaged by a massive galaxy cluster between us and the distant galaxy Explanation: The nearby galaxy—yellow blobs in the center of this image—is 1.5 billion pc from us The blue arcs are all images of a single, much more distant galaxy © 2017 Pearson Education, Inc ... image are a) b) c) d) emission nebulae nearby blue dwarf galaxies blue supergiant stars a very distant galaxy imaged by a massive galaxy cluster between us and the distant galaxy Explanation: The. .. dwarf galaxies blue supergiant stars a very distant galaxy imaged by a massive galaxy cluster between us and the distant galaxy © 2017 Pearson Education, Inc Question The blue arcs in this image... clusters a) b) c) d) e) giant ellipticals irregulars spirals active galaxies radio galaxies Explanation: The gas, dust, and disks of spiral galaxies are tidally disrupted, and even destroyed, in the