REVIEW FOR FINAL EXAM

Chapter 14: The Milky Way

1. Binary star systems

A. Are extremely rare

B. Are co-orbiting stars bound to each other by gravity

C. Contain a spectroscopic binary and an eclipsing binary

D. All of the above

2. A cloud of gas or dust in interstellar space or surrounding a star is called a

A. Nebula

B. Halo

C. Globular cluster

D. Astrometric binary

3. The material between stars is

A. A nebula

B. Dark matter

C. The interstellar medium

D. A vacuum

4. The most important line in radio astronomy is the 21-cm emission line of

A. Hydrogen

B. Helium

C. Oxygen

D. Water

5. Gas and dust between an observer and a star being observed causes _______ in the spectrum of the star.

A. A redshift

B. A blueshift

C. Absorption lines

D. Emission lines

6. The interaction of starlight with the interstellar medium may cause

A. Excitation or even ionization of the gas

B. A general dimming of starlight at all wavelengths, called interstellar extinction

C. Distant stars to look redder than they really are, called interstellar reddening

D. All of the above

7. The space between stars is

A. Inhomogeneous

B. Homogeneous

C. A vacuum

D. At a temperature of absolute 0

8. Which of the following is the largest structure?

A. Open cluster

B. Globular cluster

C. Galaxy

D. Stellar associations

9. Open clusters contain young stars and are found in the

A. Galactic disk

B. Galactic halo

C. Galactic bulge

D. Magellanic cloud

Chapter 15: Galaxies

10. Most of the mass of the Milky Way galaxy is located

A. In the central bulge

B. In a supermassive black hole

C. In the spiral arms

D. Beyond the visible edge of the disk

11. Mass that makes its presence felt by gravitational forces but that does not emit light or radiation at any wavelength is

A. neutrino

B. dark matter

C. photon

D. black hole

12. Evidence for supermassive black holes at the center of galaxies is

A. Direct observation of the black holes

B. The speed of stellar orbits around the center of galaxies

C. Decrease in luminosity at the center of galaxies

D. There is no evidence for supermassive black holes

13. The sun is located in the _______ of the Milky Way.

A. Bulge

B. Disk

C. Halo

D. Bar

14. In the ladder of distance indicators used by astronomers, which of the following techniques is used on the most nearby objects?

A. Parallax

B. Radar

C. Supernovae

D. RR Lyrae variables

15. Cepheid variables and RR Lyrae are good distance indicators because

A. They have very large radial velocities

B. They maintain a constant apparent brightness regardless of their distance

C. They have well-established period-luminosity relationships

D. Cepheid variables and RR Lyrae are not good distance indicators

16. Galaxies are classified as

A. Spiral

B. Elliptical

C. Irregular

D. All of the Above

E. A and B only

17. True/False: Elliptical galaxies may be classified as either barred or unbarred.

18. The Local Group is made up of nearby

A. Stars

B. Stars with planets

C. Galaxies

D. Globular clusters

19. The Magellanic Cloud is

A. Made up of small galaxies moving in orbits around the Milky Way

B. A nearby globular cluster

C. The star forming region of the Milky Way

D. The spherical swarm of comets that extends out to many thousands of AU from the solar system

20. The light travel time of a galaxy which is 3 megaparsec (Mpc) away is about

A. 3 years

B. 3000 years

C. 3 million years

D. 9 million years

21. Of the following, the one that is the least likely consequence of the collision of two galaxies is

1. Bursts of star formation within the galaxies.
2. Collisions of many stars within the galaxies.
3. Distortion of the appearances of the galaxies.
4. A merger of the galaxies.

22. Which of the following statements about galaxies is TRUE?

1. The diameter and luminosity of a galaxy determines its type.
2. The largest galaxies known are those of the elliptical type.
3. Most spiral galaxies are much larger than the Milky Way Galaxy.
4. It is easy to find the size of a galaxy if we know its mass.

Chapter 16: The Expanding Universe

23. If observations revealed that all galaxies showed blueshifts, with a size of blueshift that increased in proportion to the distance, this universe would be

A. Static

B. Expanding

C. Contracting

D. Cannot be determined from this information

24. Which of the following is true of the universe?

A. The expansion has no center

B. The space between galaxies is itself expanding

C. The rate of expansion increases with increasing distance

D. All of the above are true

25. By comparing the radial velocity for galaxies with his distance estimates for them, ________ was the first person to conclusively show that our universe is expanding.

A. Kepler

B. Doppler

C. Einstein

D. Hubble

26. The Hubble relation

A. Expresses how recession velocity increases with distance from the observer

B. Is NOT a law of nature

C. Can be expressed as v = H₀d

D. All of the above

27. Which of the following is NOT true of the Hubble constant?

A. It is the slope of the plot of the Hubble relation, the ratio of velocity to distance

B. It is denoted by the symbol H₀

C. It is known to an exact number

D. It indicates the size and age of the universe

28. The best estimate of the Hubble constant is

A. 700 m/s/Mpc

B. 10 km/s/Mpc

C. 70 km/s/Mpc

D. 500 Km/s/Mpc

29. Gravitational lensing of the most distant objects is usually caused by

A. Galaxies

B. Globular clusters

C. The sun

D. Earth

30. Gravitational lensing

A. Was NOT predicted by general relativity

B. May result in a galaxy’s image being stretched into a perfect ring, called an Einstein ring

C. May result in a complete obstruction of the light of a distant object by a more close object

D. All of the above

31. Quasars

A. Are believed to be distant galaxies in which the light from an active nucleus completely swamps the light from its surroundings

B. Are believed to be powered by super-massive black holes.

C. Both A and B

D. Neither A or B

32. The shortest time scale for the fluctuation in brightness of AGN (Active Galactic Nuclei) is

A. Minutes

B. Days

C. Years

D. There is no fluctuation in brightness

33. Which of the following is not considered a type of AGN?

A. Quasars

B. Cepheids

C. Seyferts

D. Blazars

34. The fact that quasars typically have very great redshifts leads directly to the conclusion that

1. Quasars must be quite small in order to travel so rapidly.
2. Are moving at speeds that exceed the speed of light.
3. Were amongst the earliest objects to form in the universe.
4. Emit more red radiation than blue radiation, suggesting they are cooling off as they move rapidly in space.

Chapter 17: Cosmology

35. Arno Penzias and Robert Wilson, two engineers at Bell Telephone Laboratory won the Nobel Prize for accidentally detecting the first evidence of radiation left over from the big bang. This radiation, which is easily detected by radio telescope anywhere on earth, is at a temperature of approximately

A. 0 K

B. 2.7 K

C. 273 K

D. 1000 K

36. True/False: The temperature of the microwave background is perfectly uniform.

37. The __________ is defined as all matter and energy in existence anywhere, observable or not

A. Galaxy

B. Universe

C. Solar System

D. Milky Way

38. A light beam which is shined parallel to the surface of the earth will be deflected __________ by gravity.

A. up

B. down

C. left

D. right

39. Einstein's most well known equation states

A. F = ma

B. l*T = constant

C. g = (G*m₁*m₂) / r²

D. E = mc²

40. Which of the following is NOT a type of space?

A. flat space

B. spherical space

C. conical space

D. hyperbolic space

41. Which of the following is NOT considered to be evidence of the big bang

A. The abundance of the lightest elements can be explained by fusion in the universe when it was young, dense, and hot (cosmic nucleosynthesis).

B. Space is filled with the radiation from the early hot phase, now diluted and reduced in energy to the level of microwaves (cosmic microwave background).

C. Galaxies are taking part in a universal expansion, as indicated by the linear relationship between distance and redshift (the Hubble relation)

D. All of these ARE considered to be evidence of the big bang.

42. In this type of universe, the universe reaches a maximum size and then collapses

A. Flat

B. Closed

C. Open

D. Empty

43. If the ultimate fate of a hypothetical universe is infinite expansion, the density of this universe must be

A. Less than the critical density

B. More than the critical density

C. Equal to the critical density

D. 70 km/s/Mpc

44. The universe becomes homogeneous on a scale of _______ and higher.

A. 1 AU

B. 1 light-year

C. 10 Mpc

D. 300 Mpc

45. Based on current observations, dark matter makes up about what percent of the total mass of the universe?

A. 1 %

B. 10 %

C. 50 %

D. 90 %

46. Who called the cosmological constant the "greatest mistake of his career"?

A. Einstein

B. Newton

C. Galileo

D. Hubble

47. True/False: There are regions of the universe whose light has yet to reach Earth.

48. These diagrams are often use to depict relativistic events

A. HR diagrams

B. Space-time diagrams

C. Vinn diagram

D. Einstein diagram

49. The heaviest element produced in the fusion reactions during the initial few minutes of the big bang was

A. Helium

B. Lithium

C. Oxygen

D. Lead

50. The weakest of the four fundamental forces of nature is

A. Strong nuclear force

B. Electromagnetism

C. Weak nuclear force

D. Gravity

51. The future of an expanding universe is dependent upon our knowing the

A. Rate of the expansion and the amount of matter in the universe.

B. Present "size" of the universe (i.e., how "far away" is the Big Bang from us).

C. Exact direction in the sky from which the universe first began expanding.

D. Age of the universe (i.e., how long ago the Big Bang occurred).

52. The age of the universe is inherently difficult to determine because it

A. Requires that astronomers know the exact location that the Big Bang occurred.

B. Determine the exact number of galaxies in the universe.

C. Accurately measure the amount of helium that is produced during the proton-proton chain.

D. Detect distance indicators in the most distant galaxies.

53. What would be the implication if Dr. McGaugh discovered that neutrinos have mass, and that the mass of the universe is at least 10 times more massive than we previously thought?

A. He would be declared insane and incompetent, since it is well known that neutrinos cannot have mass.

B. The universe will expand forever.

C. We may live in an oscillating universe.

D. The universe must be infinite in size.

54. The search for dark matter is fueled by the drive to discover

A. The source of energy for quasars.

B. What causes galaxy to rotate.

C. How long the Sun is expected to live.

D. Whether the universe is open or closed.

55. At the heart of the problem in determining an accurate value for the Hubble constant is

A. The inability of astronomers to detect dark matter.

B. The failure to solve the horizon problem.

C. Determining accurate redshifts of the distant galaxies.

D. Determining accurate distances to distant galaxies.

ANSWERS

1. B

2. A

3. C

4. A

5. C

6. D

7. A

8. C

9. A

10. D

11. B

12. B

13. B

14. B

15. C

16. D

17. F

18. C

19. A

20. D

21. B

22. B

23. C

24. D

25. D

26. D

27. C

28. C

29. A

30. B

31. C

32. B

33. B

34. C

35. B

36. F

37. B

38. B

39. D

40. C

41. D

42. B

43. A

44. D

45. D

46. A

47. T

48. B

49. B

50. D

51. A

52. D

53. C

54. D

55. D