2. 1) makes up about 90% of the universe. 2) is best detected by the largest optical telescopes. 3) makes up about 10% of the matter in clusters of galaxies. 4) exists but has no observable effects on galaxies. 5) is the result of gas and dust. Question 1 Based on galactic rotation curves and motions in clusters of galaxies, dark matter
3. 1) makes up about 90% of the universe. 2) is best detected by the largest optical telescopes. 3) makes up about 10% of the matter in clusters of galaxies. 4) exists but has no observable effects on galaxies. 5) is the result of gas and dust. Question 1 Based on galactic rotation curves and motions in clusters of galaxies, dark matter
4. 1) are much rarer than collisions between stars. 2) can transform elliptical galaxies into spirals. 3) trigger Type II supernova explosions in the halo. 4) cause gas and dust clouds to collide leading to rapid star formation. Question 2 Collisions between galaxies
5. 1) are much rarer than collisions between stars. 2) can transform elliptical galaxies into spirals. 3) trigger Type II supernova explosions in the halo. 4) 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.
6. 1) globular cluster stars. 2) giant molecular clouds. 3) central bulge stars. 4) open clusters. 5) disk stars. Question 3 When spiral galaxies collide, the greatest impact occurs on their
7. 1) globular cluster stars. 2) giant molecular clouds. 3) central bulge stars. 4) open clusters. 5) disk stars. Question 3 When spiral galaxies collide, the greatest impact occurs on their
8. 1) giant ellipticals 2) irregulars 3) spirals 4) active galaxies 5) radio galaxies Question 4 Due to the density and collisions among galaxies, are rare in the centers of clusters.
9. Question 4 Due to the density and collisions among galaxies, are rare in the centers of clusters. 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. 1) giant ellipticals 2) irregulars 3) spirals 4) active galaxies 5) radio galaxies
10. 1) the source of energy is very small. 2) energy is coming from matter and antimatter. 3) the energy source is rotating rapidly. 4) a chain reaction of supernovas occurs. 5) there are many separate sources of energy in the core. Question 5 The rapid variation of brightness of quasars indicates
11. 1) the source of energy is very small. 2) energy is coming from matter and antimatter. 3) the energy source is rotating rapidly. 4) a chain reaction of supernovas occurs. 5) 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.
12. 1) as it was when the universe was one billion years old. 2) as it will be one billion years from now. 3) as it was one billion years ago. 4) as it is today, but redshifted 10% of the speed of light. 5) as it was just after the Big Bang. Question 6 A galaxy seen one billion light years away means we see it
13. 1) as it was when the universe was one billion years old. 2) as it will be one billion years from now. 3) as it was one billion years ago. 4) as it is today, but redshifted 10% of the speed of light. 5) as it was just after the Big Bang. Question 6 A galaxy seen one 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.
14. 1) a smooth, continuous, and homogenous arrangement of clusters. 2) large voids, with most of the galaxies lying in filaments and sheets. 3) a large supercluster at the center of universe. 4) 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
15. 1) a smooth, continuous, and homogenous arrangement of clusters. 2) large voids, with most of the galaxies lying in filaments and sheets. 3) a large supercluster at the center of universe. 4) 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
16. 1) total mass of stars, gas, and dark matter. 2) central supermassive black hole. 3) globular clusters. 4) magnetic fields. 5) intergalactic gas. Question 8 The lensing of a distant quasar is produced in a foreground galaxy by its
17. 1) total mass of stars, gas, and dark matter. 2) central supermassive black hole. 3) globular clusters. 4) magnetic fields. 5) intergalactic gas. Question 8 The lensing of a distant quasar is produced in a foreground galaxy by its The twin quasar AC114 has two images of the same object.
