1. A pulsar is:
a) An eclipsing binary star.
b) a rapidly rotating white dwarf emitting a beam of light that passes across the Earth.
c) a rapidly rotating neutron star emitting a beam of light that passes across the Earth.
d) a giant star that is pulsating in and out with time.
e) a planet that is periodically eclipsing a star.

2. A Type II supernova occurs when:
a) a massive star at the end of its life explodes as a supernova.
b) two neutron stars merge to form a black hole.
c) a low mass star nears the end of its life, and sheds its outer layers.
d) gas from a companion star accretes onto a white dwarf, and the total mass is greater than 1.4 solar masses.
e) a main sequence O star excites surrounding interstellar gas.

3. What object was nicknamed "L.G.M." by astronomers?
a) Betelgeuse.
b) Sagittarius A*.
c) SN 1987A.
d) The first white dwarf discovered.
e) The first neutron star discovered.

4. A pulsar is:
a) a brand new star, very recently formed.
b) a giant star in its pulsating stage, before it sheds its outer layers and becomes a planetary nebula.
c) a massive star that explodes after its core becomes iron.
d) a flare-up of nuclear reactions on the surface of a white dwarf, caused by accretion of gas from a companion.
e) regular pulses of light from a neutron star.

5. A pulsar:
a) does not spin on its axis.
b) is spinning at a very slow rate (once every 1000 years).
c) spins on its axis 1-10 times per year.
d) spins on its axis 1-1000 times per second.
e) spins on its axis 100 billion times per second.

6. A pulsar:
a. is mainly made of hydrogen (75 percent by mass).
b. is mainly carbon, with a bit of helium and oxygen.
c. has a core of iron, surrounded by layers with increasingly lighter atoms.
d. is a dense ball of neutrons.
e. is a black hole, surrounded by an accretion disk.

7. The first neutron star discovered was nicknamed:
a) the N.S.
b) SN 1987A.
c) L.G.M.
d) M.L.G.
e) Bell's star.

8. Which of the following statements are correct?
a) All pulsars are neutron stars.
b) All neutron stars are seen as pulsars from Earth.
c) All pulsars are white dwarfs.
d) All pulsars are white dwarfs in mass transfer binary systems.
e) All pulsars are rapidly-spinning protostars.

9. What causes the very regular radio `blips' from a pulsar?
a) the star is pulsating in size.
b) as the pulsar spins, a beam of light regularly sweeps across the Earth.
c) a companion is dumping gas onto the pulsar, causing bursts of nuclear fusion.
d) a companion is periodically eclipsing the pulsar.
e) an extraterrestrial civilization.

10. Synchrotron radiation is produced by:
a) a hot solid object, like the filament in a light bulb.
b) electrons in atoms jumping from lower energy levels to higher energy levels.
c) electrons in atoms jumping from higher energy levels to lower energy levels.
d) nuclear fusion only.
e) accelerated charged particles.

11. The four types of stars listed below have very different densities. The correct order, from lowest to highest density, is:
a) M3III, G2V, white dwarf, neutron star.
b) G2V, M3III, white dwarf, neutron star.
c) M3III, G2V, neutron star, white dwarf.
d) white dwarf, M3III, G2V, neutron star.
e) neutron star, white dwarf, M3III, G2.

12. What is a neutron star?
a) an object with a mass of about 1 solar mass and a diameter about the same as that of the Earth.
b) an object with a mass between 1.4 and 3 solar masses and a diameter of about 20 km.
c) a ball of gas that has never had on-going nuclear reactions.
d) a ball of carbon and/or helium and/or oxygen and/or neon held up against gravity by electron degeneracy pressure.
e) an object so dense that nothing, not even light, can escape its gravitational field.

13. A pulsar is:
a) An eclipsing binary star.
b) a white dwarf.
c) a neutron star.
d) a giant star that is pulsating in and out with time.
e) a planet that is periodically eclipsing a star.

14. What type of star may eventually evolve into a neutron star?
a) a brown dwarf.
b) an O9V star.
c) a G2V star.
d) a white dwarf.
e) a K3V star.

15. What is the upper limit to the mass of a neutron star?
a) 0.08 solar masses.
b) 1 solar mass.
c) 1.4 solar masses.
d) 3 solar masses.
e) there is no known upper limit.

16. The four objects listed below have very different densities. The correct order, from lowest to highest density, is:
a) The Sun, Sirius B, the pulsar in the center of the Crab Nebula, Betelgeuse.
b) Betelgeuse, the Sun, Sirius B, the pulsar in the center of the Crab Nebula.
c) Sirius B, Betelgeuse, the Sun, the pulsar in the center of the Crab Nebula.
d) the pulsar in the center of the Crab Nebula, Sirius B, the Sun, Betelgeuse.
e) Betelgeuse, the Sun, the pulsar in the center of the Crab Nebula, Sirius B.

17. Which of the following is closest in diameter to a neutron star?
a) the orbit of the Earth around the Sun.
b) the Sun.
c) the Earth.
d) Johnson City.
e) the head of a pin.

18. In which of the following does electron degeneracy pressure hold the core up against gravity?
a) a white dwarf star.
b) a high mass main sequence star.
c) a neutron star.
d) a one solar mass main sequence star.
e) a horizontal branch star.

19. When a charged particle is accelerated, it produces light. This kind of light is called:
a) Heat radiation.
b) Thermal radiation.
c) Synchrotron radiation.
d) Magnetic radiation.
e) RR radiation.

20. The uranium on Earth was probably produced:
a) in the core of the Sun.
b) in the core of a red giant.
c) in a white dwarf.
d) in a planetary nebula.
e) in a supernova explosion.

21. The most common elements in the Universe are:
a) hydrogen and helium.
b) carbon and oxygen.
c) iron and silicon.
d) carbon and iron.
e) carbon, nitrogen, and oxygen.

22. MV stars are:
a. the hottest known stars.
b. brown dwarfs.
c. very short-lived stars.
d. inert balls of carbon.
e. fusing hydrogen to helium in their cores.

23. The following H-R diagram shows the evolutionary track of a massive star. At the marked position along the track, what is occuring?
a) core hydrogen burning.
b) shell hydrogen burning.
c) core helium burning.
d) shell hydrogen and helium burning.
e) no nuclear reactions.

24. The following events occur in a massive star (mass greater than about 8 solar masses) during its lifetime.

1. carbon fusion in the core.
2. carbon fusion in a shell surrounding a shrinking inert oxygen core.
3. hydrogen fusion in the core.
4. explosion as a supernova.
5. silicon burning in the core.
6. radioactive decay of ⁵⁶Ni in the core.

25. An alpha capture reaction is:
a) When an ion combines with an electron.
b) When an electron and a proton combine to form a neutron and a neutrino.
c) When a helium nucleus fuses with a heavier nucleus (such as an oxygen nucleus).
d) During a supernova, when a neutron fuses with an atom.
e) When four hydrogen nuclei fuse to form a helium nucleus.

26. Which of the following chemical elements is more abundant in the Universe?
a) Sulfur.
b) Nitrogen.
c) Uranium.
d) Iron.
e) Carbon.

27. Note the H-R diagram to the right. A star that lies at the marked position has:
a) hydrogen fusion in its core.
b) helium fusion in its core.
c) no nuclear reactions in its core, but shell hydrogen fusion.
d) a radius that is shrinking with time.
e) no nuclear reactions.

28. Looking at a periodic table, determine what is produced when an alpha capture process happens to ²⁴Mg?
a) ²⁶Mg
b) ²⁶Si
c) ²⁸Al
d) ²⁸Si
e) ²⁸S

29. Which of the following chemical elements is more abundant in the Universe?
a) Uranium.
b) Silicon.
c) Iron.
d) Helium.
e) Carbon.

30. White dwarfs are made up of mainly:
a) neutrons.
b) hydrogen.
c) helium, carbon, and/or oxygen.
d) silicon, magnesium, and nickel.
e) iron.

31. The iron in our blood was probably originally produced:
a) in a main sequence star.
b) in one solar mass stars, just after they leave the main sequence.
c) in a one solar mass star, while it is on the asymptotic giant branch.
d) during the formation of a planetary nebula.
e) in a massive star, just before it explodes as a supernova.

32. An alpha particle is:
a) an ionized hydrogen atom.
b) a ²H nucleus.
c) a ⁴He nucleus.
d) a carbon-12 nucleus.
e) an ⁵⁶Fe nucleus.

33. A white dwarf has:
a) a mass of more than 3 solar masses and a diameter about the same as that of the Earth.
b) a mass between 1.4 and 3 solar masses and a diameter of about 20 km.
c) a mass between 1.4 and 3 solar masses, and a diameter about the same as that of the Earth.
d) a mass less than 1.4 solar masses, and a diameter about the same as that of the Earth.
e) a mass less than 1.4 masses, and a diameter of about 20 km.

34. Which of the following is closest in diameter to a white dwarf?
a) the orbit of the Earth around the Sun.
b) the Sun.
c) the Earth.
d) Johnson City.
e) the head of a pin.

35. In which of the following does electron degeneracy pressure hold the core up against gravity?
a) a red giant star, just before the triple-alpha process starts in the core.
b) a high mass main sequence star.
c) a brown dwarf.
d) a one solar mass main sequence star.
e) a horizontal branch star.

36. The plutonium on Earth was probably produced:
a) in the core of the Sun.
b) in the core of a red giant.
c) in a white dwarf.
d) in a planetary nebula.
e) in a supernova explosion.

37. Asymptotic giant branch stars:
a) have hydrogen fusion in their cores.
b) have helium fusion in their cores.
c) are unstable stars soon to become planetary nebulae.
d) have cores made up solely of neutrons, packed closely together.
e) probably have black holes in their centers.

38. What is the CNO cycle?
a) the process by which helium is fused into carbon, nitrogen, and oxygen.
b) the process by which carbon is fused into nitrogen and oxygen.
c) a type of hydrogen fusion which uses carbon, nitrogen, and oxygen atoms as catalysts.
d) the period of a massive stars's life, when carbon, oxygen, and nitrogen are fusing in shells around the core.
e) the period of a low-mass stars's life after all the carbon, oxygen, and nitrogen have been converted into heavier chemical elements.

39. Which of the following statements about supernovae is correct?
a) our Sun will eventually become a supernova.
b) most stars eventually explode as supernova.
c) one or two supernova are seen in the Milky Way per year.
d) about 100 Milky Way supernovae are seen per year.
e) supernovae occur approximately once every couple of hundred years in the Milky Way.

40. The following H-R diagram shows the evolutionary track of a massive star. When the star reaches the marked position along the track, what nuclear reaction begins for the first time?
a) core hydrogen burning.
b) shell hydrogen burning.
c) core helium burning.
d) core oxygen fusion.
e) core carbon fusion.

41. What is another name for a helium-4 nucleus?
a) a positron.
b) a deuterium nucleus.
c) a beta particle.
d) an alpha particle.
e) a gamma particle.

42. When a one solar mass star has evolved to become an asymptotic giant branch star, which is moving up and to the right on the H-R diagram, what is its internal structure like?
a) An inert neutron core, surrounded by multiple layers of shell burning, with increasingly light chemical elements from silicon to hydrogen.
b) Core helium burning, surrounded by a shell of hydrogen burning.
c) An inert carbon core, surrounded by a shell of helium burning and a shell of hydrogen burning.
d) Hydrogen fusion in the core, surrounded by a shell of helium burning.
e) An iron core, surrounded by multiple layers of shell burning, with increasingly light chemical elements from silicon to hydrogen.

43. The diagram to the right shows the evolutionary path of a star. The star leaves the main sequence, moves up and to the right, then moves back to the left. At the point marked `here', when the star is moving back to the left on the H-R diagram, what is occuring in the core of the star?
a) hydrogen fusion.
b) helium fusion.
c) carbon fusion.
d) no fusion; the core is shrinking.
e) no fusion; the core is held up against gravity by electron degeneracy pressure.

44. Which of the following chemical elements is more abundant in the Universe?
a) Sulfur.
b) Silicon.
c) Uranium.
d) Magnesium.
e) Oxygen.

45. A planetary nebula is:
a) An interstellar gas cloud in the process of creating a star and solar system.
b) The expanding outer layers of a dying star that are ionized by the hot core of the star.
c) A gas cloud created by the explosion of a massive star.
d) A dense molecular cloud.
e) A ionized gas cloud surrounding a main sequence O star.

46. Which of the following elements are ONLY produced during supernova explosions?
a) carbon.
b) oxygen.
c) magnesium.
d) uranium.
e) nitrogen.

47. Looking at a periodic table, determine what is produced when an alpha capture process happens to ²⁰Ne?
a) ²⁰Mg
b) ²⁴Si
c) ²⁴Mg
d) ²⁸Si
e) ²⁸S

48. What is the ultimate fate of an isolated white dwarf, that does not interact closely with another object?
a) It becomes a brown dwarf.
b) It becomes a black dwarf.
c) It remains the same temperature and size indefinitely.
d) It slowly expands and becomes less dense, until it finally dissipates into the interstellar medium.
e) It continues to contract, until finally it becomes a ball of neutrons.

49. When a one solar mass star first leaves the main sequence, and starts moving through the subgiant (IV) portion of the H-R diagram, what is occuring inside the star?
a) helium fusion in the core, hydrogen fusion in a shell surrounding the core.
b) hydrogen fusion in the core, helium fusion in a shell surrounding the core.
c) no fusion in the core, hydrogen fusion in a shell surrounding the core.
d) no fusion in the core, helium fusion in a shell surrounding the core.
e) carbon fusion in the core, helium fusion in a shell surrounding the core.

50. Which of the following types of stars have main sequence lifetimes longer than the current age of the Universe?
a) 09V.
b) M5V.
c) A1V.
d) G2V.
e) B1V.

51. A star cluster is observed to have a full main sequence, from M stars to O stars. Approximately how old is this cluster?
a) Less than a few million years old.
b) 100 million years old.
c) 1 billion years old.
d) 10 billion years old.
e) 1 trillion years old.

52. Inspect the H-R diagram to the right. Stars that lie at position X:
a) have main sequence lifetimes of about trillion years.
b) have main sequence lifetimes of 10 billion years.
c) have main sequence lifetimes of 1 billion years.
d) have main sequence lifetimes of 1 million years.
e) live forever.

53. Which of the following statements is true about the lifetimes of main sequence stars?
a) Lower luminosity main sequence stars live longer than higher luminosity main sequence stars.
b) Main sequence A stars live longer than main sequence K stars.
c) Hot main sequence stars live longer than cool main sequence stars.
d) The greater the mass of a star, the longer its main sequence lifetime.
e) All main sequence A stars ever formed are still main sequence A stars.

54. What is the relationship between the mass and the luminosity of a main sequence star, approximately?
a) the luminosity is inversely proportional to the mass.
b) the luminosity is inversely proportional to the mass squared.
c) the luminosity is proportional to the mass.
d) the luminosity is proportional to the mass to the fourth power.
e) the luminosity does not depend upon mass; all main sequence stars have the same mass.

55. A star cluster is observed to have a main sequence that extends up to G stars, with no more luminous main sequence stars seen. Approximately how old is this cluster?
a) A few million years old.
b) 100 million years old.
c) 1 billion years old.
d) 10 billion years old.
e) 1 trillion years old.

56. Interstellar dust:
a) Absorbs UV and optical light.
b) Emits infrared light.
c) Scatters UV and optical light.
d) Makes background stars appear redder than they really are.
e) All of the above.

57. In what wavelength regime is the peak of the thermal spectrum of interstellar dust grains?
a) Infrared.
b) Optical.
c) X-ray.
d) Ultraviolet.
e) Gamma Rays.

58. Which of the following statements is true about the lifetimes of main sequence stars?
a) Lower luminosity main sequence stars live longer than higher luminosity main sequence stars.
b) Main sequence A stars live longer than main sequence K stars.
c) Hot main sequence stars live longer than cool main sequence stars.
d) The greater the mass of a star, the longer its main sequence lifetime.
e) All main sequence A stars ever formed are still main sequence A stars.

59. The age of a star cluster is equal to:
a) The main sequence lifetime of the lowest mass star in the cluster.
b) The main sequence lifetime of the star at the top of the observed main sequence in the H-R diagram of the star cluster.
c) All star clusters in the Milky Way formed about 10 billion years ago.
d) All star clusters in the Milky Way formed about 1 million years ago.
e) All star clusters in the Milky Way are 13.7 billion years old.

60. The angular momentum of a spinning object is proportional to its:
a) mass X radius.
b) mass X spin velocity.
c) mass X spin velocity X radius.
d) mass X spin velocity X radius².
e) mass X spin velocity² X radius.

61. The best-known example of a ring galaxy is the Cartwheel galaxy. This was likely formed by:
a) the merger of two spiral galaxies of equal mass.
b) an elliptical galaxy evolving into a spiral galaxy.
c) the head-on collision between a small galaxy and a disk galaxy.
d) a central black hole eating away at the center of the galaxy, producing a ring.
e) two equal-mass spiral galaxies interacting, producing tidal tails that resemble a ring.

62. A galaxy with a large bulge relative to the disk and tightly wrapped spiral arms is most likely a/an:
a) Sc galaxy.
b) E0 galaxy.
c) S0 galaxy.
d) Sd galaxy.
e) Sa galaxy.

63. Who was the first person to classify spiral and elliptical galaxies into sub-types according to their appearance?
a) Henrietta Leavitt.
b) Harlow Shapley.
c) Edwin Hubble.
d) William Herschel.
e) Robert Trumpler.

64. The long tails seen in visible light photographs of the Antennae galaxies were produced from:
a) tidal forces during the collision of two spiral galaxies.
b) tidal forces during the collision of two elliptical galaxies.
c) jets of charged particles from a massive black hole.
d) the head-on collision of a dwarf elliptical galaxy and a disk galaxy.
e) the galaxy probably originally formed in that shape, for unknown reasons.

65. When a small galaxy passes through the center of the disk of a large spiral galaxy, traveling in a direction perpendicular to the plane of the disk:
a) a ring galaxy is formed.
b) many of the stars in the two galaxies collide, causing numerous supernova.
c) all of the stars from the small galaxy fall into the central black hole of the larger galaxy.
d) an elliptical galaxy is formed.
e) the small galaxy hits the large galaxy, and bounces back in the direction it came from.

66. The Hubble Tuning Fork diagram is:
a) a plot of velocity vs. distance.
b) a diagram showing the different types of galaxies, in order from ellipticals to irregulars.
c) a map of the Local Group.
d) a plot of velocity vs. Right Ascension.
e) a `slice of the Universe' plot.

67. Rotation curves of galaxies are plots of:
a) Orbital period vs. Hubble type.
b) Number of stars vs. distance from center.
c) Circular orbital velocity vs. distance from center.
d) Hubble type vs. roundness of shape.
e) Hubble type vs. circular orbital velocity.

68. The massive black hole in the center of our galaxy is called:
a) Cygnus X-1.
b) The Schwarzchild object.
c) L.G.M.
d) RR Lyrae.
e) Sagittarius A*.

69. Collisions between galaxies:
a) cause large numbers of stars to collide, and therefore explode.
b) turn ellipticals into spirals.
c) may trigger the formation of many new stars.
d) almost never occur.
e) may occur, but there is no evidence for them.

70. An Sb galaxy is:
a) a giant elliptical galaxy with huge megaparsec-long jets shooting out of the center.
b) a galaxy similar to the Milky Way.
c) a spiral galaxy with an extremely luminous nucleus.
d) a spiral galaxy with a pulsar in the center.
e) a pair of galaxies connected by a stellar bridge, with long stellar tails extending out into space.

71. Evidence for dark matter in the Universe includes:
a) lots of gamma rays coming from random directions in the sky.
b) the fast orbital velocities of the planets around the Sun.
c) the fast orbital velocities of gas and stars in the outer part of the Milky Way.
d) there is no observational evidence for dark matter; it is just a theoretical idea.
e) the existence of pulsars.

72. The ring-like structure of the Cartwheel galaxy was probably formed by:
a) a massive black hole in the center of the galaxy devoured the stars in the inner part of the galaxy, leaving only an outer ring remaining.
b) a smaller galaxy passed through the center, creating a ring.
c) it probably collided with another galaxy more massive than itself.
d) the stars in the inner regions exploded as supernovae, leaving a large hole in the center.
e) scientists have no idea why this galaxy has a ring-like structure.

73. The instability strip is:
a) a spiral wave pattern in a galaxy.
b) the boundary around a black hole: the point of no return.
c) the part of the H-R diagram where Cepheid variables and RR Lyrae stars lie.
d) in a binary pair, the position where the gravitational pull of the two stars is equal.
e) the upper mass limit to a white dwarf.

74. In the Milky Way, almost all interstellar gas clouds are found:
a) Only in the halo.
b) In the bulge, disk, and halo.
c) Only in the disk.
d) Only in the bulge.
e) Only in the spiral arms.

75. What observations did Harlow Shapley make that indicated that the Sun was not the center of the Milky Way?
a) observations of the angular sizes of open clusters.
b) observations of variable stars in nearby galaxies.
c) observations of variable stars in globular clusters.
d) observations of interstellar dust clouds.
e) he counted up the number of individual stars in many directions in the sky.

76. What produces the 21 cm radio line used to map the rotation curve of the Milky Way?
a) atomic hydrogen.
b) ionized hydrogen.
c) molecular hydrogen.
d) carbon monoxide.
e) interstellar dust.

77. Compared with the Sun, most stars in the halo of the Milky Way are:
a) younger, redder, and have less heavy chemical elements.
b) younger, bluer, and have more heavy chemical elements.
c) older, redder, and have less heavy chemical elements.
d) older, bluer, and have more heavy chemical elements.
e) older, redder, and have more heavy chemical elements.

78. What is the evidence for dark matter in the Milky Way Galaxy?
a) There is much more infrared radiation coming from the Milky Way than can be accounted for by the known normal stars and interstellar clouds.
b) There is much more visible light coming from the Milky Way than can be accounted for by the known normal stars and interstellar clouds.
c) There is much more radio waves coming from the Milky Way than can be accounted for by the known normal stars and interstellar clouds.
d) The circular velocities of gas and stars in the outer part of the Milky Way are higher than can be accounted for by the known stars and interstellar clouds.
e) The circular velocities of gas and stars in the outer part of the Milky Way are less than can be accounted for by the known stars and interstellar clouds.

79. The mass of the Milky Way Galaxy is about:
a) 2 X 10⁸ solar masses
b) 2 X 10⁶ solar masses
c) 6 X 10¹¹ solar masses
d) 6000 solar masses
e) 2 X 10⁴ solar masses

80. Which of the following are generally only found in the disk and spiral arms of the Milky Way?
a) O and B stars.
b) globular clusters.
c) 0.3 solar mass main sequence stars.
d) white dwarf stars.
e) KV and MV stars.

81. Cepheid variable stars are:
a) are used to determine the distances to other galaxies.
b) are less luminous than RR Lyrae stars.
c) are main sequence O stars.
d) vary with periods of about 1-10 seconds.
e) all of the above.

82. Approximately how long does it take the Sun to orbit the Milky Way?
a) 4.6 billion years.
b) 225 million years.
c) 1 million years.
d) 1000 years.
e) 10 years.

83. In the Milky Way, globular clusters are found:
a) In the bulge, halo, and disk.
b) Only in the disk.
c) Only in the halo.
d) Only in the spiral arms.
e) Only in dense molecular clouds.

84. The Sun's location in the Milky Way is:
a) near the center.
b) in the halo.
c) in the disk, about two-thirds of the way out from the center.
d) in the bulge.
e) in a globular cluster.

85. If all the stars in the bulge of the Milky Way were replaced by a black hole with the same mass, then:
a) The Sun would be drawn into this black hole.
b) The velocity at which the Sun orbits the Galactic Center would decrease.
c) The velocity at which the Sun orbits the Galactic Center would increase.
d) The velocity at which the Sun orbits the Galactic Center would stay the same.
e) The Sun would fly off in a straight line into intergalactic space.

86. In the Milky Way, HII regions are found:
a) Only in the halo.
b) In the bulge, disk, and halo.
c) Only in the disk.
d) Only in the bulge.
e) In the bulge and disk, but not in the halo.

87. What astronomical accomplishment is Henrietta Leavitt best remembered for?
a) She mapped the distribution of globular clusters in the Milky Way using RR Lyrae stars, and showed that the Sun was NOT in the center of the Milky Way.
b) She estimated the distance to the Andromeda galaxy using Cepheid variable stars, and found it was OUTSIDE the Milky Way.
c) She discovered the period-luminosity relationship for Cepheid variable stars.
d) She was the first person to look at the Milky Way with a telescope, and showed that it is made up of many stars.
e) She discovered the four biggest moons of Jupiter.

88. Approximately how many times has the Sun orbited the Milky Way?
a) a billion times.
b) a million times.
c) 20 times.
d) 1 time.
e) it has never orbited the Milky Way; during the entire life of the Sun, it has only moved a tiny fraction of the full circumference of the Milky Way.

89. An RR Lyrae star is:
a) An eclipsing binary star.
b) A white dwarf in a mass-transfer binary system.
c) A neutron star in a mass-transfer binary system.
d) A variable star which can be used for distance determination.
e) A post-AGB star.

90. Jupiter has a mass about 300 times the mass of the Earth. If Jupiter turned into a black hole with the same mass, but nothing else changed,
a) its moon Europa would be pulled into the black hole.
b) its moon would orbit around Jupiter at a distance equal to the Schwarzchild radius of the black hole.
c) Europa would continue in its same orbit.
d) the entire solar system would be pulled into this black hole.
e) the Schwarzchild radius of this black hole would be about 3000 km.

91. The "point of no return" around a black hole, inside which one cannot escape from, is called the:
a) The Chandrasekhar limit.
b) The Lagrange point.
c) The gravitational lens.
d) The event horizon.
e) The Pauli Exclusion limit.

92. Imagine you are in a rocketship, about 10 Schwarzchild radii away from a black hole. Which of the following would you NEVER observe?
a) X-ray radiation coming out from within the Schwarzchild radius of the black hole.
b) A shift in the apparent position of nearby stars, due to the gravitational effect of the black hole.
c) Very strong tidal forces from the black hole.
d) A shift in the wavelength of light from stars in the direction opposite that of the black hole.
e) Your clocks will run slower than clocks back home on Earth.

93. Which of the following has the smallest radius?
a) a 1 solar mass white dwarf.
b) a 2 solar mass neutron star.
c) a 1 solar mass black hole.
d) a 100 solar mass black hole.
e) a million solar mass black hole.

94. The Schwarzchild radius of a black hole is:
a) The radius of the singularity.
b) The distance between the black hole and its associated white hole.
c) The radius of the event horizon.
d) The distance from the black hole where the gravitational field from the black hole is zero.
e) The distance from the black hole at which you would be pulled apart by tidal forces.

95. Harlow Shapley:
a) Provided the first conclusive evidence that `spiral nebulae' are outside the Milky Way.
b) Identified the emission lines from pulsars.
c) Discovered the Period-Luminosity relation for Cepheid variables.
d) Measured the distances to globular clusters, and concluded the Sun was NOT in the center of the Milky Way.
e) Made a 3-dimensional map of the Milky Way by counted stars and estimating brightnesses, and concluded that the Sun WAS in the center of the Milky Way.

96. Henrietta Leavitt:
a) Provided the first conclusive evidence that `spiral nebulae' are outside the Milky Way.
b) Identified the emission lines from pulsars.
c) Discovered the Period-Luminosity relation for Cepheid variables.
d) Measured the distances to globular clusters, and concluded the Sun was NOT in the center of the Milky Way.
e) Made a 3-dimensional map of the Milky Way by counted stars and estimating brightnesses, and concluded that the Sun WAS in the center of the Milky Way.

97. The diameter of the disk of the Milky Way is approximately:
a) 300 A.U.
b) 10 light years.
c) 100 thousand light years.
d) a billion light years.
e) a billion billion light years.

98. Where in the Milky Way are Type II supernovae usually located?
a) only in the disk.
b) only in the halo.
c) only at the very center.
d) only in the bulge.
e) in the disk, halo, and bulge.

99. From the orbital velocity of the Sun around the Milky Way, 220 km/s, and the distance from the Sun to the center of the Galaxy, using the relationship V² = GM/R, one can calculate a mass. This is the mass of:
a) the Sun.
b) Sgr A*.
c) the entire Milky Way.
d) the part of the Milky Way that is outside of the Sun's orbit.
e) the part of the Milky Way galaxy that is inside of the Sun's orbit.

100. Synchrotron radiation is produced by:
a) a hot solid object, like the filament in a light bulb.
b) electrons in atoms jumping from lower energy levels to higher energy levels.
c) electrons in atoms jumping from higher energy levels to lower energy levels.
d) nuclear fusion only.
e) accelerated charged particles.

101. Who discovered the period-luminosity relationship for Cepheid variable stars?
a) Harlow Shapley.
b) Edwin Hubble.
c) Adriaan van Maanen.
d) William Herschel.
e) Henrietta Leavitt.

102. Who first measured the distances to globular clusters, and concluded that the Sun was NOT in the center of the Milky Way?
a) Harlow Shapley.
b) Edwin Hubble.
c) Adriaan van Manaan.
d) William Herschel.
e) Henrietta Leavitt.

103. Which of the following objects are NOT generally found in the bulge of the Milky Way, but only in the disk?
a) planetary nebulae.
b) open clusters.
c) white dwarfs.
d) Supernovae Type I.
e) globular clusters.

104. Sagittarius A* is:
a) the brightest supernovae seen in the last 300 years.
b) a small irregular galaxy in orbit around the Milky Way.
c) a 10 solar mass black hole in a mass-transfer binary system with a giant star.
d) a 2 million solar mass black hole in the center of the Milky Way.
e) the first pulsar ever discovered.

105. A black hole is:
a) the end stage of stellar evolution for an isolated 1 solar mass star.
b) produced during a nova.
c) produced by an explosion of a white dwarf in a mass transfer system.
d) a really massive object (greater than 10⁶ solar masses).
e) an object with an escape velocity greater than the speed of light.

106. When a charged particle is accelerated, it produces light. This kind of light is called:
a) Heat radiation.
b) Thermal radiation.
c) Synchrotron radiation.
d) Magnetic radiation.
e) RR radiation.

107. What provided the first evidence of the existence of large quantities of dark matter in the Universe?
a) The light curves of galaxies.
b) The rotation curves of galaxies.
c) Mapping the distribution of globular clusters in the Milky Way.
d) The discovery of the period-luminosity relationship for Cepheids.
e) The discovery of pulsars.

108. An RR Lyrae star is:
a) a white dwarf star undergoing mass transfer from a companion.
b) a neutron star undergoing mass transfer from a companion.
c) a star that lies above the main sequence on an HR diagram, in the instability strip.
d) a white dwarf that has cooled to become very dim.
e) a neutron star with a beam of light that regularly sweeps across the Earth.

109. The radius of the event horizon of a black hole is called the:
a) Shapley radius.
b) Synchrotron radius.
c) Pauli radius.
d) Schwarzchild radius.
e) Wormhole radius.

110. What phenomenon was observed during the 1919 total solar eclipse?
a) The positions of stars behind the Sun appeared shifted.
b) The velocity of the light from stars near the Sun appeared faster than normal.
c) The velocity of the light from stars near the Sun appeared slower than normal.
d) Light from the Sun was observed to be gravitationally blueshifted.
e) All of the above.

111. How far is the Sun from the center of the Milky Way?
a) 8 light years.
b) 8 parsecs.
c) 8 kiloparsecs.
d) 8 A.U.
e) the Sun is at the center of the Milky Way.

112. Who made the first map of the Milky Way by using his telescope to count the stars towards many directions in the sky?
a) Harlow Shapley.
b) Edwin Hubble.
c) Adriaan van Maanen.
d) William Herschel.
e) Henrietta Leavitt.

113. On the H-R diagram, Cepheids variables lie:
a) below and to the left of the main sequence.
b) below and to the right of the main sequence.
c) on the far right above the main sequence, in the MIII star region.
d) on the main sequence, in the upper left of the diagram.
e) above the main sequence in the instability strip.

114. Most of the following objects are mainly found in the plane of the disk of the Milky Way, but usually not in the bulge or the halo. Which is the exception, being commonly found in the bulge and halo as well as the disk?
a) HII regions.
b) Molecular clouds.
c) Open clusters.
d) Globular clusters.
e) O and B stars.

115. The first person to find evidence that the Sun is not in the center of the Milky Way was:
a) Henrietta Leavitt.
b) Harlow Shapley.
c) Edwin Hubble.
d) William Herschel.
e) Robert Trumpler.

Answers: 1c, 2a, 3e, 4e, 5d, 6d, 7c, 8a, 9b, 10e, 11a, 12b, 13c, 14b, 15d, 16b, 17d, 18a, 19c, 20e, 21a, 22e, 23d, 24c, 25c, 26e, 27c, 28d, 29d, 30c, 31e, 32c, 33d, 34c, 35a, 36e, 37c, 38c, 39e, 40c, 41d, 42c, 43b, 44e, 45b, 46d, 47c, 48b, 49c, 50b, 51a, 52b, 53a, 54d, 55d, 56e, 57a, 58a, 59b, 60c, 61c, 62e, 63c, 64a, 65a, 66b, 67c, 68e, 69c, 70b, 71c, 72b, 73c, 74c, 75c, 76a, 77c, 78d, 79c, 80a, 81a, 82b, 83a, 84c, 85d, 86c, 87c, 88c, 89c, 90c, 91d, 92a, 93c, 94c, 95d, 96c, 97c, 98a, 99e, 100e, 101e, 102a, 103b, 104d, 105e, 106c, 107b, 108c, 109d, 110a, 111c, 112d, 113e, 114d, 115b.