Test 3, Form B

1. The object shown in Slide~1 is

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

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

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

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

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

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

a) a tidally distorted galaxy.
b) an edge-on spiral galaxy.
c) a background galaxy that has been gravitationally lensed.
d) an elliptical 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) we live in a spiral galaxy.
b) the universe is expanding.
c) there is cold dust in the plane of the Milky Way Galaxy.
d) the Big Bang was not perfectly homogeneous.
e) the Earth is moving through space.

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

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

7. Most of the mass of the Milky Way galaxy

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

8. Our Sun

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

9. The stars in the halo of our Galaxy

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

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

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

11. The stars of an open cluster

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

12. Small galaxies that orbit close to the Milky Way

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

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

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

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

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

15. Which has the shortest lifetime?

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

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

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

17. A long time ago, the universe

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

18. The coldest clouds of interstellar material

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

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

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

20. Which does not exist in a spiral galaxy?

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

21. In general, the faster a spiral galaxy rotates

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

22. According to the Hubble Law,

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

23. RR Lyrae stars and Cepheid variables

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

24. You would expect normal elliptical galaxies

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

25. The oldest stars in the Milky Way galaxy

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

26. Globular clusters

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

27. Olber's paradox states that

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

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

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

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

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

30. 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 acceleration of the universe.
d) the average density (or total mass) of the universe.
e) the value of the Hubble Constant.

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

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

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

33. We believe most of the helium in the universe

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

34. The small fluctuations we observe in the microwave background

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

35. The Big Bang theory does not explain

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

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

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

37. A standard candle is

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

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

39. Cold atomic hydrogen gas in space can be viewed

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

40. In a spiral galaxy

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

41. When galaxies collide

a) elliptical galaxies may be formed.
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) only a few stars will collide; the rest will form a spiral pattern.
e) Nothing -- galaxies rarely, if ever, collide with each other.

42. Most of the galaxies in the Local Group

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

43. If the universe is closed, then

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

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

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

45. 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 G main-sequence star
c) the white dwarf
d) the M main-sequence star
e) the Cepheid variable

46. The cosmological principle states that

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

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

48. Which cluster is the youngest? -- C

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

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