Multiple-Choice Questions
1) Rotation curves for spiral galaxies show
A) they are slowing down.
B) rotation speed drops off further from the nucleus.
C) most have dark halos.
D) most of the mass lies in the nucleus.
E) no relation to mass.
Page Ref: 16.1
2) How massive are the largest known galaxies?
A) a few million solar masses
B) a hundred million solar masses
C) a few billion solar masses
D) a trillion solar masses
E) hundreds of trillions of solar masses
Page Ref: 16.1
3) As we look at larger and larger scales in the universe, we find
A) smaller and smaller masses.
B) almost exclusively visible matter.
C) a larger and larger percentage of the matter is visible.
D) a larger and larger percentage of the matter is dark.
E) an equal amount of visible and dark matter.
Page Ref: 16.1
4) Mapping the intracluster gas is best done with
A) the Arecibo radio dish.
B) the HST with hydrogen alpha light.
C) the Chandra X-ray Observatory in space.
D) the Keck telescope in the infrared.
E) the COBE satellite in microwaves.
Page Ref: 16.1
5) The type of radio galaxy that reveals its motion through the intergalactic medium is called a
A) quasar.
B) dual lobe.
C) bi-polar jet.
D) head-tail.
E) Seyfert.
Page Ref: 16.1
6) Based on galactic rotation curves and cluster dynamics, we think dark matter
A) is a minor component of the entire mass of the universe.
B) is best detected from the x-rays it produces in the intergalactic medium.
C) will have no effect on the fate of the universe.
D) comprises over 90% of the entire mass of the universe.
E) will doom the universe to collapse, overcoming the red shifts we now observe.
Page Ref: 16.1
7) You observe a radio galaxy whose lobes are swept back as if forming a tail. You conclude
A) this is evidence for intergalactic matter.
B) the galaxy is about to evolve into a spiral.
C) the galaxy is isolated, not part of a cluster.
D) the galaxy is moving towards Earth.
E) there must be another galaxy nearby.
Page Ref: 16.1
8) Collisions between galaxies is thought to
A) have stopped about 5 billion years ago.
B) be commonplace.
C) have never occurred.
D) be extremely rare.
E) have only occurred between 10 and 15 billion years ago.
Page Ref: 16.2
9) Collisions between galaxies
A) are much rarer than collisions between stars.
B) can turn elliptical galaxies into spirals.
C) cause large numbers of stars to collide and explode.
D) cause the gas and dust clouds to collide, leading to rapid star formation.
E) are the best explanation for gamma-ray burst events.
Page Ref: 16.2
10) What is true of spiral galaxies?
A) They are much less common at larger redshifts.
B) They are relatively rare in regions of high galaxy density.
C) They are only found in the center of rich galaxy clusters.
D) They have never been seen to have large redshifts.
E) They evolve from giant ellipticals.
Page Ref: 16.3
11) Astronomer's believe that a spiral galaxy may form
A) from a collision between a small and large galaxy.
B) due to a quasar shutting down.
C) from the sudden contraction of an elliptical galaxy.
D) from the collision of two giant elliptical galaxies.
E) from the explosion of a dwarf irregular galaxy.
Page Ref: 16.3
12) Which of these is the next evolutionary track for the Large Magellanic Cloud?
A) Contraction into a spiral.
B) Expansion into a giant elliptical.
C) It will become a satellite galaxy of Andromeda.
D) It will be free of our Local Group.
E) Collision with the Milky Way.
Page Ref: 16.3
13) The pregalactic blobs had masses similar to
A) the earth.
B) the Sun.
C) globular clusters.
D) the Large Magellanic Cloud.
E) the Milky Way.
Page Ref: 16.3
14) According to the HST data, very distant (and early) galaxies tend to be
A) larger and bluer that modern galaxies.
B) nothing but quasars.
C) smaller, bluer, and more irregular than modern ones.
D) redder, due to the recession of the universe.
E) very well formed into clusters of nothing but spirals.
Page Ref: 16.3
15) What is true of galaxies at the larger redshifts compared to ones nearby?
A) They appear smaller and more irregular.
B) They appear larger and more regular.
C) They are redder.
D) They are almost all ellipticals.
E) They are mostly giants.
Page Ref: 16.3
16) The Height of the quasar epoch was
A) 5 billion years ago.
B) when there was still sufficient mass to fuel the supermassive black holes at their center.
C) before the formation of galaxies.
D) less than 1 billion years ago.
E) before mass had a chance to accumulate at the nucleus.
Page Ref: 16.4
17) In its most energetic phase, a quasar can probably only last
A) a few days.
B) a few years.
C) a few thousand years.
D) a few million years.
E) a few billion years.
Page Ref: 16.4
18) A galaxy that was once a quasar is likely to
A) have burned all its fuel by now and be dark.
B) now be a dwarf irregular.
C) have a black hole at its nucleus.
D) still be a quasar.
E) be less than 5 billion years old.
Page Ref: 16.4
19) If the merger theory is correct, the brightest active galactic nuclei should
A) be in the smallest elliptical galaxies.
B) contain the youngest stars.
C) contain the least mass.
D) contain supermassive black holes.
E) form small irregular galaxies.
Page Ref: 16.4
20) The quasars with the largest presently known redshifts are close to
A) .96.
B) 3.
C) 6.
D) 10.
E) 65.
Page Ref: 16.4
21) Gravitational lensing of distant, faint irregular galaxies may be the key to
A) mapping the dark matter.
B) quasar energy production.
C) understanding galactic rotation curves.
D) understanding active galactic nuclei.
E) determining galactic redshifts.
Page Ref: 16.5
22) Red shift surveys give us
A) an idea of how turbulent the intergalactic gas is.
B) a 3-D layout of galaxies in space.
C) the total mass of the universe.
D) a more accurate census of the Local Group.
E) a better value of the speed of light.
Page Ref: 16.5
23) That some quasars show absorption spectra with a smaller redshift than their emission spectra indicates
A) we still don't understand redshifts.
B) they are much closer than previously thought.
C) there is cooler gas between us and the quasar.
D) their black holes are still contracting.
E) their black holes are still expanding.