Test 4 Review Clicker Question

1. Test 4 Review Clicker Question Chs 13,14,15,16,&17

2. Question 13-1 a) matter spiraling into a large black hole. b) the collision of neutron stars in a binary system. c) variations in the magnetic fields of a pulsar. d) repeated nova explosions. e) All of the above are possible. One possible explanation for a gamma-ray burster is

3. Question 13-1 a) matter spiraling into a large black hole. b) the collision of neutron stars in a binary system. c) variations in the magnetic fields of a pulsar. d) repeated nova explosions. e) All of the above are possible. One possible explanation for a gamma-ray burster is Gamma-ray bursts vary in length, and the coalescence of two neutron stars seems to account for short bursts.

4. Question 13-2 a) NASA’s latest X-ray orbiting telescope. b) a millisecond pulsar with three planets. c) the strongest X-ray eclipsing binary system. d) a likely black hole binary star system. e) the first gamma-ray burster spotted in X rays. Cygnus X-1 is

5. Question 13-2 a) NASA’s latest X-ray orbiting telescope. b) a millisecond pulsar with three planets. c) the strongest X-ray eclipsing binary system. d) a likely black hole binary star system. e) the first gamma-ray burster spotted in X rays. Cygnus X-1 is Cygnus X-1 is an X-ray source with one visible star orbited by an unseen companion of at least 10 solar masses, and very rapid changes in the signal indicating a small source.

6. Question 13-3 a) a beam of light. b) a massive object. c) neutrinos. d) antimatter. e) All of the above are correct. The force of gravity can pull on

7. Question 13-3 a) a beam of light. b) a massive object. c) neutrinos. d) antimatter. e) All of the above are correct. The force of gravity can pull on Gravity is described by general relativity as a bending of space, and all particles, including photons, move through warped space along curved paths.

8. Question 13-4 a) Earth’s orbit would not change. b) Earth would be pulled into the black hole. c) X rays would destroy Earth. d) Earth would be torn apart from the tidal force. e) life would be unchanged. If the sun was replaced by a one-solar-mass black hole

9. Question 13-4 a) Earth’s orbit would not change. b) Earth would be pulled into the black hole. c) X rays would destroy Earth. d) Earth would be torn apart from the tidal force. e) life would be unchanged. If the sun was replaced by a one-solar-mass black hole The force of gravity depends only on mass and distance, not the type of matter, or its size.

10. Question 13-5 a) is the point where X rays emerge. b) is the physical surface of the hole. c) defines the outer edge of an accretion disk. d) is measured by the Schwarzschild radius. e) extends for millions of miles into space. The event horizon of a black hole

11. Question 13-5 a) is the point where X rays emerge. b) is the physical surface of the hole. c) defines the outer edge of an accretion disk. d) is measured by the Schwarzschild radius. e) extends for millions of miles into space. The event horizon of a black hole The event horizon is the surface of an imaginary sphere around a collapsed object inside of which nothing, including light, can escape.

12. Question 14-1 a) supernova remnants. b) white dwarf stars in the spiral arms. c) red giant variable stars in globular clusters. d) bright O and B stars in open clusters. e) X-ray sources. The location of the galactic center was identified using

13. Question 14-1 a) supernova remnants. b) white dwarf stars in the spiral arms. c) red giant variable stars in globular clusters. d) bright O and B stars in open clusters. e) X-ray sources. The location of the galactic center was identified using Harlow Shapley used pulsating RR-Lyrae variables as distance indicators to the globular clusters. He then deduced the distance and direction of the Milky Way’s center.

14. Question 14-2 a) about 30 Kpc from the center in the halo. b) 30,000 light-years from the center in a globular cluster. c) at the outer edge of the galactic disk, in the plane. d) about halfway from the center, in the spiral arms. e) in the bulge, near the Orion arm. Our Sun is located in the Milky Way Galaxy

15. Question 14-2 a) about 30 Kpc from the center in the halo. b) 30,000 light-years from the center in a globular cluster. c) at the outer edge of the galactic disk, in the plane. d) about halfway from the center, in the spiral arms. e) in the bulge, near the Orion arm. Our Sun is located in the Milky Way Galaxy The Sun orbits the center of the Galaxy within the disk, taking about 225 million years to complete one orbit.

16. Question 14-3 a) measuring distances with Cepheid variable stars. b) identifying the mass of the Galaxy’s central black hole. c) determining the masses of stars in an eclipsing binary system. d) using spectroscopic parallax to measure distances to stars. The period – luminosity relationship is a crucial component of

17. Question 14-3 a) measuring distances with Cepheid variable stars. b) identifying the mass of the Galaxy’s central black hole. c) determining the masses of stars in an eclipsing binary system. d) using spectroscopic parallax to measure distances to stars. The period – luminosity relationship is a crucial component of Cepheid variable stars with longer periods have higher actual luminosities; short-period Cepheids are dimmer.

18. Question 14 - 4 High-speed motion of gas and stars near the Milky Way Galaxy’s center is explained by a) tidal forces from the Andromeda Galaxy. b) accretion disks around neutron stars. c) gamma-ray bursts. d) gravitation from globular clusters. e) a supermassive black hole.

19. Question 14 - 4 High-speed motion of gas and stars near the Milky Way Galaxy’s center is explained by a) tidal forces from the Andromeda Galaxy. b) accretion disks around neutron stars. c) gamma-ray bursts. d) gravitation from globular clusters. e) a supermassive black hole. Recent observations estimate the black hole to be 4 million solar masses.

20. Question 14 - 5 a) a spiral galaxy. b) a barred spiral galaxy. c) an elliptical galaxy. d) a quasar. e) an irregular galaxy. Detailed measurements of the disk suggest that our Milky Way is

21. Question 14 - 5 a) a spiral galaxy. b) a barred spiral galaxy. c) an elliptical galaxy. d) a quasar. e) an irregular galaxy. Detailed measurements of the disk suggest that our Milky Way is Measurements of stellar motion in and near the bulge imply that it is football shaped, about half as wide as it is long, characteristic of a barred spiral galaxy.

22. Question 14 - 6 a) the Sun’s mass and velocity in orbit around the galactic center b) the rotation of the bulge and disk components c) the Sun’s age and age of globular cluster stars d) the motion of spiral arms and the mass of the central black hole e) the Sun’s orbital period and distance from the center What two observations allow us to estimate the Galaxy’s mass?

23. Question 14 - 6 a) the Sun’s mass and velocity in orbit around the galactic center b) the rotation of the bulge and disk components c) the Sun’s age and age of the globular cluster stars d) the motion of spiral arms and mass of the central black hole e) the Sun’s orbital period and distance from the center What two observations allow us to estimate the Galaxy’s mass? Use the modified form of Kepler’s law to find the mass: Total mass = (orbital size)3 / (orbital period)2

24. Question 14 - 7 a) the spiral arms formed first. b) the globular clusters formed first. c) the disk component started out thin and grew. d) spiral density waves formed first. e) the bar in the bulge formed first. In the formation of our Galaxy

25. Question 14 - 7 a) the spiral arms formed first. b) the globular clusters formed first. c) the disk component started out thin and grew. d) spiral density waves formed first. e) the bar in the bulge formed first. In the formation of our Galaxy Globular clusters contain very old stars, no gas or dust, and orbit around the center randomly.

26. Question 14 - 8 a) the waves penetrate dusty cocoons to reveal star formation. b) it reflects from the Galaxy’s core. c) the waves are not absorbed by galactic black holes. d) it can be used to map out the cool hydrogen in spiral arms. e) radio waves provide a distance measurement like parallax. 21-cm radio radiation is useful in studying our Galaxy because

27. Question 14 - 8 a) the waves penetrate dusty cocoons to reveal star formation. b) it reflects from the Galaxy’s core. c) the waves are not absorbed by galactic black holes. d) it can be used to map out the cool hydrogen in spiral arms. e) radio waves provide a distance measurement like parallax. 21-cm radio radiation is useful in studying our Galaxy because The Doppler shifts of 21-cm radiation from hydrogen in the spiral arms provides astronomers with a tool to map out the Galaxy’s structure.

28. Question 14 - 9 a) OB associations b) open clusters c) giant molecular clouds d) emission nebulae e) Population II red giant stars Which of these is not a typical part of our Galaxy’s spiral arms?

29. Question 14 - 9 a) OB associations b) open clusters c) giant molecular clouds d) emission nebulae e) Population II red giant stars Which of these is not a typical part of our Galaxy’s spiral arms? The spiral arms contain gas, dust, molecular clouds, new clusters, and Population I stars.

30. Question 14 - 10 a) 21-cm maps of the spiral arms b) the rotation curve of the outer edges of the Galaxy c) orbits of open clusters in the disk d) infrared observations of new star- forming regions e) X-ray images of other galaxies What suggests that the mass of our Galaxy extends farther than its visible disk?

31. Question 14 - 10 a) 21-cm maps of the spiral arms b) the rotation curve of the outer edges of the Galaxy c) orbits of open clusters in the disk d) infrared observations of new star- forming regions e) X-ray images of other galaxies What suggests that the mass of our Galaxy extends farther than its visible disk? The outer edges of the Galaxy’s disk rotate much faster than they should. Most of the mass of the Galaxy must be dark matter.

32. Question 15 - 1 a) disk and spiral arms. b) halo. c) central bulge. d) open clusters. e) companion galaxies, the Magellanic Clouds. Based on their shapes and stars, elliptical galaxies are most like the Milky Way’s

33. Question 15 - 1 a) disk and spiral arms. b) halo. c) central bulge. d) open clusters. e) companion galaxies, the Magellanic Clouds. Based on their shapes and stars, elliptical galaxies are most like the Milky Way’s Like the stars and globular clusters in our halo, elliptical galaxies contain little or no gas and dust to make new stars.

34. Question 15 - 2 a) ongoing star formation b) a disk, bulge, and halo c) globular clusters in the halo d) open clusters in the disk e) all of the above What property is shared by spiral galaxies?

35. Question 15 - 2 a) ongoing star formation b) a disk, bulge, and halo c) globular clusters in the halo d) open clusters in the disk e) all of the above What property is shared by spiral galaxies? M-51, a Type Sb spiral

36. Question 15 - 3 a) giant globular clusters in the halo. b) small irregular galaxies that orbit the Milky Way. c) large molecular clouds in the disk of our Galaxy. d) the brightest ionized hydrogen regions in our Galaxy. e) spiral nebulae originally discovered by Herschel. The Magellanic Clouds are

37. Question 15 - 3 a) giant globular clusters in the halo. b) small irregular galaxies that orbit the Milky Way. c) large molecular clouds in the disk of our Galaxy. d) the brightest ionized hydrogen regions in our Galaxy. e) spiral nebulae originally discovered by Herschel. The Magellanic Clouds are

38. Question 15 - 4 a) Most galaxies showed redshifts. b) All galaxies showed blueshifts. c) Galaxies showed about half redshifts and half blueshifts. d) Galaxies showed no line shifts at all. e) Some galaxies showed a redshift that changed into a blueshift at other times. Hubble took spectra of galaxies in the 1930s. What did he find?

39. Question 15 - 4 a) Most galaxies showed redshifts. b) All galaxies showed blueshifts. c) Galaxies showed about half redshifts and half blueshifts. d) Galaxies showed no line shifts at all. e) Some galaxies showed a redshift that changed into a blueshift at other times. Hubble took spectra of galaxies in the 1930s. What did he find? Redshifts of galaxies indicate they are moving away from us.

40. Question 15 - 5 a) more distant galaxies showing greater blueshifts. b) distant quasars appearing proportionally dimmer. c) more distant galaxies showing greater redshifts. d) slowly varying Cepheid variables appearing brighter. e) more distant galaxies appearing younger. Hubble’s law is based on

41. Question 15 - 5 a) more distant galaxies showing greater blueshifts. b) distant quasars appearing proportionally dimmer. c) more distant galaxies showing greater redshifts. d) slowly varying Cepheid variables appearing brighter. e) more distant galaxies appearing younger. Hubble’s law is based on

42. Question 15 - 6 a) the density of galaxies in the universe. b) the luminosity of distant galaxies. c) the reddening of light from dust clouds. d) the speed of a galaxy. e) the rate of expansion of the universe. Hubble’s constant measures

43. Question 15 - 6 a) the density of galaxies in the universe. b) the luminosity of distant galaxies. c) the reddening of light from dust clouds. d) the speed of a galaxy. e) the rate of expansion of the universe. Hubble’s constant measures Hubble’s law relates how fast galaxies are moving away from us at different distances. A larger value for H0 implies a faster expansion rate. Velocity = H0 x Distance

44. Question 15 - 7 a) the size of the universe. b) distances to galaxies. c) the speed of recession of galaxies. d) the density of matter in the universe. e) the temperature of the Big Bang. To calibrate Hubble’s constant, astronomers must determine

45. Question 15 - 7 a) the size of the universe. b) distances to galaxies. c) the speed of recession of galaxies. d) the density of matter in the universe. e) the temperature of the Big Bang. To calibrate Hubble’s constant, astronomers must determine Distances to galaxies are determined using a variety of “standard candles,” including Cepheid variables, supernova explosions, model galaxies, and model clusters.

46. Question 15 - 8 a) the universe is static. b) the universe is collapsing. c) the universe is expanding. d) the Milky Way is the center of the universe. e) There is no accepted interpretation. Hubble’s discovery of galaxy redshifts means

47. Question 15 - 8 a) the universe is static. b) the universe is collapsing. c) the universe is expanding. d) the Milky Way is the center of the universe. e) There is no accepted interpretation. Hubble’s discovery of galaxy redshifts means

48. Question 15 - 9 a) they generate energy partly through H to He fusion like stars. b) they show spectra similar to extremely bright O stars. c) their luminosity varies like eclipsing binary stars. d) in short exposure photographs, their images appear stellar. e) they are dense concentrations of millions of stars. Quasars are “quasi-stellar” because

49. Question 15 - 9 a) they generate energy partly through H to He fusion like stars. b) they show spectra similar to extremely bright O stars. c) their luminosity varies like eclipsing binary stars. d) in short exposure photographs, their images appear stellar. e) they are dense concentrations of millions of stars. Quasars are “quasi-stellar” because Although short-exposure images can appear starlike, many quasars show jets or other signs of intense activity.

50. Question 15 - 10 a) supermassive black holes at their cores. b) dark matter. c) self-sustaining star formation. d) spiral density waves. e) hypernova explosions. Seyfert and radio galaxies could be powered by