Test 3, Form A

1. The object shown in Slide~1 is

a) a globular star cluster.
b) an open star cluster.
c) a cluster of galaxies.
d) an irregular galaxy.
e) an elliptical galaxy.

2. The galaxy shown in Slide~2 has a Hubble type of

a) Sc
b) Irr
c) Sa
d) SBc
e) E0

3. The object shown in Slide~3 is an example of

a) a barred spiral galaxy.
b) a star-forming region.
c) an Sa spiral galaxy.
d) two galaxies colliding.
e) a globular star cluster.

4. Slide~4 shows a cluster of galaxies. The thin arc that the arrow is pointing to is

a) an elliptical galaxy.
b) a tidally distorted galaxy.
c) a background galaxy that has been gravitationally lensed.
d) an edge-on spiral galaxy.
e) foreground interstellar matter in the Milky Way.

5. Slide~5 shows a picture of the microwave background made by the COBE satellite. The picture shows that one side of the sky is hotter than the other. This is because

a) the Earth is moving through space.
b) the universe is expanding.
c) the Big Bang was not perfectly homogeneous.
d) we live in a spiral galaxy.
e) there is cold dust in the plane of the Milky Way Galaxy.

6. Our Sun

a) is located within a spiral arm of our Galaxy.
b) is located in our Galaxy's disk, but between its spiral arms.
c) is located near the center of our Galaxy.
d) is located in the halo of our Galaxy.
e) is located within an open cluster.

7. The stars in the halo of our Galaxy

a) are rich in metals.
b) orbit in random directions.
c) are usually obscured by dust.
d) are called A stars.
e) are usually in open clusters.

8. The cosmological principle states that

a) the universe must appear similar, no matter where you are in it.
b) the universe must be expanding.
c) the universe must appear similar, no matter when you live in it.
d) the Earth must be at the center of the universe.
e) the universe must be finite.

9. When galaxies collide

a) only a few stars will collide; the rest will form a spiral pattern.
b) the stars inside them collide and go supernova.
c) the galaxies will pass through each other and never feel the other's presence.
d) elliptical galaxies may be formed.
e) Nothing -- galaxies rarely, if ever, collide with each other.

10. Which has the shortest lifetime?

a) an F main sequence star
b) a G main sequence star
c) a B main sequence star
d) a K main sequence star
e) a white dwarf

11. RR Lyrae stars and Cepheid variables

a) are main sequence stars.
b) are pulsars.
c) cannot be observed in other galaxies.
d) have the same absolute magnitude.
e) have temperatures and luminosities that place them in the instability strip.

12. Which of the following is least interesting to a cosmologist who is studying the origins and fate of the universe.

a) the abundance of metals in B-main sequence stars.
b) the age of globular clusters.
c) the value of the Hubble Constant.
d) the acceleration of the universe.
e) the average density (or total mass) of the universe.

13. A galaxy-size, spherical gas cloud that is rotating very slowly

a) will dissipate itself into space.
b) will form an elliptical galaxy.
c) can never form stars.
d) will not collapse until it collides with something.
e) will wind up collapsing into a flat disk.

14. According to the Hubble Law,

a) Olber's paradox is wrong.
b) the universe must be closed.
c) the greater the distance to a galaxy, the larger its Doppler redshift.
d) the stars in our Galaxy are moving away from us.
e) the universe must expand forever.

15. Which is not evidence for the existence of dark matter?

a) the movement of galaxies in clusters.
b) the rotation of spiral galaxies.
c) the gravitational deflection of background light by galaxy clusters.
d) the amount of star formation which occurs within a spiral galaxy.
e) all of the above presents evidence for dark matter.

16. The coldest clouds of interstellar material

a) are usually found around O main sequence stars.
b) are transparent to optical light.
c) are usually found far above the Galactic plane.
d) are called H~II regions.
e) contain organic molecules.

17. Most of the supernovae that occur in our Galaxy are

a) in the Galaxy's bulge, where the density of stars is greatest.
b) in the spiral arms, since they contain youngest stars.
c) far in the Galaxy halo, where no other stars are around.
d) between the spiral arms, where the stellar populations are mixed.
e) in globular clusters, since they contain the oldest stars.

18. We believe most of the helium in the universe

a) was created in globular cluster red giant stars.
b) was created during the collisions of galaxies.
c) was created in the Big Bang.
d) was created during the explosions of supernovae.
e) was created inside of main-sequence stars.

19. Two galaxies clusters the same distance from Earth, have the same number of galaxies. However in cluster (a), the galaxies orbit (in random directions) with an average velocity of 500 kilometers per second. In cluster (b), the galaxies' average speed is 2000 kilometers per second. Based on this, we can say

a) cluster (a) is older than cluster (b).
b) cluster (a) is moving away from us faster than cluster (b).
c) cluster (a) is less massive than cluster (b).
d) cluster (a) is younger than cluster (b).
e) cluster (a) has a larger fraction of spiral galaxies than cluster (b).

20. A G main sequence star, an M main-sequence star, an RR Lyrae, star, a white dwarf, and a Cepheid variable star all have the same apparent magnitude. Which is furthest away?

a) the RR Lyrae star
b) the M main-sequence star
c) the white dwarf
d) the Cepheid variable
e) the G main-sequence star

21. The distance to the center of our Galaxy was first calculated by

a) measuring the velocities of clouds of atomic hydrogen.
b) measuring the distances to open clusters.
c) measuring the distances to Cepheid variables.
d) comparing our Galaxy with other galaxies.
e) measuring the distances to globular clusters.

22. A standard candle is

a) any object whose Doppler shift is known.
b) any object whose distance is known.
c) any object whose apparent magnitude is known.
d) any object whose absolute magnitude is known.
e) any object which changes its brightness.

23. In a spiral galaxy

a) there are many high-mass stars between the spiral arms.
b) there are many low-mass stars between the spiral arms.
c) there are many globular clusters between the spiral arms.
d) there are no stars between the spiral arms.
e) there are many H~II regions between the spiral arms.

24. Astronomers have difficulty studying the structure of the Milky Way Galaxy. The reason for this is that

a) the plane of our Galaxy is filled with dust, which obscures our view.
b) most of the Milky Way's stars are too far away to study with telescopes.
c) the nearby stars obstruct our view of more distant stars.
d) most of the Milky Way's stars are moving away from us, due to the Hubble law.
e) most of the stars in our Galaxy are too red to see.

25. A long time ago, the universe

a) had more microwave photons than it does today.
b) was less dense than it is today.
c) was cooler than it is today.
d) had more elliptical galaxies than it does today.
e) had more interacting/colliding galaxies than it does today.

26. To understand how the universe will expand in the future, we need to know the Hubble Constant,

a) the total amount of dark matter and the total amount of dark energy.
b) the total amount of dark matter and the total amount of heavy elements.
c) the temperature of the microwave background and the brightness of the microwave background.
d) the total amount of heavy elements and the total amount of dark energy.
e) the total amount of dark matter and the temperature of the microwave background.

27. Cepheid variables stars cannot be used to measure the Hubble Constant. This is because

a) they are obscured by dust.
b) they are not bright enough to be seen at such large distances.
c) they do not exist in other galaxies.
d) they have too large a Doppler shift to be seen.
e) they are poor standard candles.

28. Which does not exist in a spiral galaxy?

a) Red giant stars.
b) Cepheid variable stars.
c) RR Lyrae stars.
d) Globular clusters.
e) All these objects exist in spiral galaxies.

29. According to what we (think we) know about the accerlation of the universe, the more the universe expands

a) the more galaxy collisions will occur.
b) the more matter that will be formed.
c) the faster it will expand.
d) the greater the energy of the microwave photons.
e) the greater the influence of gravity.

30. Olber's paradox states that

a) the Earth must be at the center of the universe.
b) the Hubble law is due to the Big Bang.
c) the universe must appear similar, no matter when you live in it.
d) if the universe were infinite, the night sky would be bright.
e) the universe cannot have a center.

31. The Big Bang theory does not explain

a) why the universe appears to have a temperature of 3 degrees above absolute zero.
b) why there are no stars older than about 14 billion years.
c) why one out of every 10 atoms in the universe is helium.
d) how metals are created.
e) why galaxies are moving away from each other.

32. In which type of object would you expect to find the most H~I gas?

a) a globular cluster.
b) an S0 galaxy
c) an SBa galaxy
d) an Sc galaxy
e) an elliptical galaxy

33. If the universe is closed, then

a) the universe was expanding more slowly in the past.
b) it will expand forever.
c) galaxy clusters could not exist.
d) it is infinite.
e) someday all the galaxies will appear blue-shifted.

34. The oldest stars in the Milky Way galaxy

a) are all red giants.
b) are all located in spiral arms.
c) have almost no metals in them.
d) are all in open clusters.
e) are all white dwarf stars.

35. Most of the galaxies in the Local Group

a) have no interstellar matter.
b) are large spiral galaxies.
c) are small dwarf galaxies.
d) do not have any Population~II stars.
e) are giant elliptical galaxies.

36. You would expect normal elliptical galaxies

a) to be moving towards us.
b) to contain almost no RR Lyr stars.
c) to appear red.
d) to be orbiting the Milky Way.
e) to appear blue.

37. By observing Cepheid variables in the Magellanic Clouds, Henriertta Leavitt found

a) the brighter the Cepheid, the longer it took to pulsate.
b) the brighter the Cepheid, the more likely it was a Population II star.
c) the brighter the Cepheid, the larger its Doppler redshift.
d) the brighter the Cepheid, the faster it was rotating.
e) all Cepheids were the same brightness.

38. Small galaxies that orbit close to the Milky Way

a) are standard candles.
b) cause star formation to occur in the Galaxy's halo.
c) are called spiral galaxies.
d) can get ripped apart by tidal forces.
e) do not have dark matter.

39. Globular clusters

a) have more B main sequence stars than open clusters.
b) are Population I objects.
c) are more massive than open clusters.
d) are found in the disk of our Galaxy.
e) contain fewer RR Lyrae stars than open clusters.

40. Outside our Local Group of nearby galaxies, RR Lyrae stars are useless as distance indicators. This is because

a) they do not exist in other galaxies.
b) they have too large a Doppler shift to be seen.
c) they are obscured by dust.
d) they are poor standard candles.
e) they are not bright enough to be seen at such large distances.

41. Most of the mass of the Milky Way galaxy

a) is presently in star clusters.
b) is presently in the interstellar medium.
c) is presently in stars.
d) is presently in the spiral arms.
e) is in some form that we know nothing about.

42. At the center of an H~II region is probably

a) a Cepheid variable star.
b) a globular cluster.
c) an elliptical galaxy.
d) several O and B main sequence stars.
e) a spiral galaxy.

43. In general, the faster a spiral galaxy rotates

a) the more massive (and luminous) it is.
b) the younger it is.
c) the further away it is.
d) the smaller its bulge.
e) the more irregular it is in shape.

44. Cold atomic hydrogen gas in space can be viewed

a) via its optical absorption of stellar light.
b) via its optical emission lines.
c) via its 21 cm emission line radiation.
d) via its x-ray emission.
e) via its blackbody microwave radiation.

45. The small fluctuations we observe in the microwave background

a) were damped out over time.
b) demonstrate that the universe is closed.
c) are evidence against the Big Bang theory.
d) are the result of star formation that occurred billions of years ago.
e) are the precursors of today's large galaxy clusters.

46. The stars of an open cluster

a) have a range of ages and metallicites.
b) are young and metal-rich.
c) are young and metal-poor.
d) are old and metal-poor.
e) are old and metal-rich.

47. Which is likely to be the diagram of a globular cluster? -- A

48. Which cluster is the youngest? -- B

49. Which cluster is the most distant? -- D

50. Which is least likely to be found in an elliptical galaxy? -- B