1. 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.

2. In the Milky Way, 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.

3. 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.

4. 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.

5. 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.

6. 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.

7. How did Robert Trumpler prove that there is interstellar dust in the Milky Way?
a) He mapped the distribution of globular clusters in the Milky Way using RR Lyrae stars. These distances were closer than expected, implying interstellar dust absorption.
b) He estimated the distance to the Andromeda galaxy using Cepheid variable stars, and found it was closer than expected, implying interstellar dust absorption.
c) He discovered the period-luminosity relationship for Cepheid variable stars. This showed that these stars are closer than expected, implying interstellar dust absorption.
d) He calculated the distances to open clusters using both brightness and angular size measurements, and found larger distances from the brightness measurements, implying interstellar dust.
e) He counted the number of stars in many position in the sky, and showed that the Sun was in the center of this distribution, indicating large amounts of interstellar dust.

8. The present estimate for the mass of the Milky Way Galaxy is:
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

9. Which of the following are 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.

10. 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.

11. Approximately how long does it take the Sun to orbit the Milky Way?
a) 4.6 billion years.
b) 240 million years.
c) 1 million years.
d) 1000 years.
e) 10 years.

12. How did Edwin Hubble prove that the `spiral nebulae' are galaxies like the Milky Way?
a) By observing the proper motion of the stars in the spiral arms.
b) From stellar parallax measurements.
c) By observing the light curves of Cepheid variable stars in the galaxies.
d) By measuring X-ray emission from the black holes in the centers of the galaxies.
e) By comparing photographs of the galaxies taken at different times, and observing the rotation of the galaxies.

13. 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.

14. 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.

15. 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.

16. The closest rich cluster of galaxies, the Virgo Cluster,
a) only contains spiral galaxies: no ellipticals.
b) has in its center the Milky Way Galaxy.
c) is very similar to the Local Group in terms of numbers and types of galaxies.
d) contains several quasars.
e) has giant elliptical galaxies near its center.

17. 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.

18. The Large Magellanic Cloud is:
a) in the Great Wall.
b) an irregular galaxy orbiting the Milky Way.
c) the host galaxy of a quasar.
d) a molecular cloud in the Orion Nebula.
e) a giant elliptical galaxy, in the center of the Local Group.

19. Which of the following is a typical characteristic of an elliptical galaxy?
a) contains many main sequence O and B stars.
b) contains large quantities of interstellar matter.
c) has bulge and a flattened disk.
d) has spiral arms in its disk.
e) is a flattened sphere of mostly older stars.

20. On the astronomical distance ladder, what is the second-to-last step from the top, the step before Hubble's Law?
a) Cepheid variables.
b) Spectroscopic parallax.
c) Standard candles.
d) Stellar parallax.
e) the Galactic Center.

21. 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.

22. The Zone of Avoidance is:
a) a very large `wall' of galaxies at a distance of 100 Mpc.
b) very large `bubbles' seen in 3-dimensional maps of the Universe, in which very few galaxies are seen.
c) the galaxy supercluster that we live in.
d) the plane of the Milky Way.
e) the plane of the solar system.

23. Which of the following have NOT provided astronomers with evidence for dark matter in the Universe?
a) measurements of rotation curves of spiral galaxies.
b) measurements of the temperature of hot gas in galaxy clusters.
c) measurements of average velocities and ranges in velocities of galaxies in clusters.
d) measurements of the rotation curves of planets orbiting the Sun.
e) measurements of average velocities and ranges in velocities of stars in elliptical galaxies.

Answers: 1c, 2c, 3c, 4a, 5c, 6d, 7d, 8c, 9a, 10a, 11b, 12c, 13a, 14c, 15d, 16e, 17a, 18b, 19e, 20c, 21b, 22d, 23d.