Deck 17: Hubbles Law and Dark Matter: the Large-Scale Structure of the Cosmos

Question 1

Galaxies contain less mass as dark matter than as visible stars.

Answer 1

False

Question 2

The Andromeda galaxy will eventually collide with the Milky Way.

Answer 2

True

Question 3

In the larger clusters, colliding galaxies tend to pass through one another.

Answer 3

True

Question 4

The masses of most spiral galaxies, like ours, are a few billion solar masses.

Question 5

Because of the great masses and speeds involved, Newton's laws are useless in measuring the mass of a galaxy.

Question 6

Mapping the intracluster gas is largely done with red light from the ionized emission lines of hot hydrogen.

Question 7

Both spiral and elliptical galaxies seem to have dark halos of similar proportions relative to their visible matter.

Question 8

The total mass of a galaxy tends to be only slightly larger than the visible mass.

Question 9

As with stars, binary galaxy pairs are useful in finding their total mass.

Question 10

Collisions between galaxies have little effect on the individual stars.

Question 11

Head- tail radio galaxies reveal their motion through the intergalactic gas with a tail- like structure.

Question 12

For nearby galaxies, determining the rotation curve allows us to calculate the mass.

Question 13

Galactic collisions mostly involve interactions between gas and dust clouds rather than individual stars.

Question 14

Most of the matter in the universe is dark matter.

Question 15

There are large amounts of superhot intergalactic matter.

Question 16

When galaxies collide, the large- scale galactic structure is affected, but most of the individual stars are not.

Question 17

The stability of clusters of galaxies suggests that there is between 10 and 100 times as much dark matter as visible in the galaxies.

Question 18

The percentage of dark matter in galactic clusters is less than the percentage in individual galaxies.

Question 19

Galactic collisions are believed to be commonplace.

Question 20

The largest known galaxies contain about 10 billion solar masses.

Question 21

The rapid decline in quasars 10 billion years ago signifies a rapid decline in galactic mergers.

Question 22

No binary black hole has ever been detected.

Question 23

Virgo A (M87) is probably a dead quasar, but our Milky Way is not.

Question 24

Hubble reveals the most distant (first) galaxies were bluer than those of today.

Question 25

The brightest active galaxies are giant ellipticals.

Question 26

Astronomers have discovered two black holes in the process of merging.

Question 27

The "Great Wall" is the structure in the Large Magellanic Cloud near where Supernova 1987A occurred.

Question 28

The pregalactic blobs started with masses comparable to big globular clusters.

Question 29

Quasars may come from mergers of black holes in early galaxies.

Question 30

It is currently believed that superclusters lie on the surfaces of "bubbles" in space.

Question 31

Our theories of galaxy formation are just as well developed and tested as are our theories of star and planet formation.

Question 32

Most galaxies are isolated in space.

Question 33

There is presently no evidence for large- scale structure bigger than about 200 Mpc.

Question 34

The Milky Way is at the center of our Local Supercluster.

Question 35

Galactic evolution is due to collisions between galaxies.

Question 36

Like supernovae, quasars must end with a violent explosion.

Question 37

The more its central black hole was fed, the more likely the galaxy was to show up as a quasar.

Question 38

Supermassive galaxies are found at the core of rich galaxy clusters.

Question 39

Mergers between equally massive galaxies usually produce elliptical galaxies.

Question 40

In its early stages, the Milky Way was probably a quasar.

Question 41

Rotation curves for spiral galaxies show

A) most have dark halos.
B) most of the mass lies in the nucleus.
C) they are slowing down.
D) rotation speed drops off further from the nucleus.
E) no relation to mass.

Question 42

Beyond the scale of superclusters, galaxies are randomly distributed throughout the universe.

Question 43

As we look at larger and larger scales in the universe, we find

A) smaller and smaller masses.
B) a larger and larger percentage of the matter is visible.
C) almost exclusively visible matter.
D) a larger and larger percentage of the matter is dark.
E) an equal amount of visible and dark matter.

Question 44

Collisions between galaxies

A) cause large numbers of stars to collide and explode.
B) are the best explanation for gamma- ray burst events.
C) cause the gas and dust clouds to collide, leading to rapid star formation.
D) are much rarer than collisions between stars.
E) can turn elliptical galaxies into spirals.

Question 45

Redshift surveys are designed to find which galaxies are oldest and youngest.

Question 46

The pregalactic blobs had masses similar to

A) the Earth.
B) the Milky Way.
C) the Sun.
D) dwarf galaxies.
E) open clusters of stars.

Question 47

Collisions between galaxies are thought to

A) be commonplace.
B) have only occurred between 10 and 15 billion years ago.
C) have stopped about 5 billion years ago.
D) be extremely rare.
E) have never occurred.

Question 48

The Great Wall is a huge sheet of galaxies that stretches for over 100 Mpc.

Question 49

Which of these is the next evolutionary track for the Large Magellanic Cloud?

A) collision with the Milky Way
B) It will become a satellite galaxy of Andromeda.
C) expansion into a giant elliptical
D) contraction into a spiral
E) It will be free of our Local Group.

Question 50

Based on galactic rotation curves and cluster dynamics, we think dark matter

A) comprises over 90% of the entire mass of the universe.
B) is best detected from the X- rays it produces in the intergalactic medium.
C) is a minor component of the entire mass of the universe.
D) will doom the universe to collapse, overcoming the redshifts we now observe.
E) will have no effect on the fate of the universe.

Question 51

The type of radio galaxy that reveals its motion through the intergalactic medium is called a

A) dual lobe.
B) head- tail.
C) quasar.
D) Seyfert.
E) bipolar jet.

Question 52

A radio galaxy whose lobes are swept back as if forming a tail probably indicates

A) the galaxy is isolated, not part of a cluster.
B) evidence for intergalactic matter.
C) the galaxy is moving towards Earth.
D) the galaxy is about to evolve into a spiral.
E) there must be another galaxy nearby.

Question 53

When we see a doubling of the image of single quasar, the body creating the gravity lens is just a brown dwarf close to us.

Question 54

What is true of spiral galaxies?

A) They evolve from giant ellipticals.
B) They are much less common at larger redshifts.
C) They are relatively rare in regions of high galaxy density.
D) They have never been seen to have large redshifts.
E) They are only found in the center of rich galaxy clusters.

Question 55

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

Question 56

The greater the mass of the foreground cluster of galaxies, the more warped the images of the distant galaxies are when they undergo gravitational lensing.

Question 57

Quasars were used to determine the size of the Local Supercluster.

Question 58

Astronomers believe that a spiral galaxy may form

A) from a collision between a small and a large galaxy.
B) from the collision of two giant elliptical galaxies.
C) due to a quasar shutting down.
D) from the sudden contraction of an elliptical galaxy.
E) from the explosion of a dwarf irregular galaxy.

Question 59

The absorption lines we find in quasar redshifts that arise from intervening gas clouds show even larger redshifts than the quasar spectra, due to dust absorption.

Question 60

Mapping the intracluster gas is best done with

A) the Arecibo radio dish.
B) the COBE satellite in microwaves.
C) the HST with hydrogen alpha light.
D) the Chandra X- ray Observatory in space.
E) the Keck telescope in the infrared.

Question 61

The largest presently known redshifts of quasars are close to

A) 0.96.
B) 3.
C) 7.
D) 10.
E) 65.

Question 62

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.

Question 63

According to the HST data, very distant (and early) galaxies tend to be

A) larger and bluer that modern galaxies.
B) very well formed into clusters of nothing but spirals.
C) nothing but quasars.
D) redder, due to the recession of the universe.
E) smaller, bluer, and more irregular than modern ones.

Question 64

The galaxies that reveal their motion through the intergalactic medium are called
.

Question 65

Clusters appear to have dark matter than their individual galaxies.

Question 66

The primary factor for galactic evolution is .

Question 67

From studies of the rotations of galaxies and dynamics of clusters, we now think that about
of the mass of the universe is composed of dark matter.

Question 68

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) be less than 5 billion years old.
E) still be a quasar.

Question 69

There is no obvious evidence for large- scale structure greater than about

A) 200 kpc.
B) 600 kpc.
C) 200 Mpc.
D) 600 Mpc.
E) 2000 Mpc.

Question 70

What is true of galaxies at the larger redshifts compared to ones nearby?

A) They appear smaller and more irregular.
B) They are mostly giants.
C) They are redder.
D) They are almost all ellipticals.
E) They appear larger and more regular.

Question 71

Some quasars show absorption spectra with a smaller redshift than their emission spectra. This indicates that

A) they are much closer than previously thought.
B) we still don't understand redshifts.
C) there is cooler gas between us and the quasar.
D) their black holes are still contracting.
E) their black holes are still expanding.

Question 72

If the merger theory is correct, the brightest active galactic nuclei should

A) contain the youngest stars.
B) contain the least mass.
C) contain supermassive black holes.
D) form small irregular galaxies.
E) be in the smallest elliptical galaxies.

Question 73

Gravitational lensing of distant, faint irregular galaxies may be the key to

A) determining galactic redshifts.
B) quasar energy production.
C) mapping dark matter.
D) understanding active galactic nuclei.
E) understanding galactic rotation curves.

Question 74

Redshift surveys give us

A) an idea of how turbulent the intergalactic gas is.
B) a better value of the speed of light.
C) a more accurate census of the Local Group.
D) the total mass of the universe.
E) a 3- D layout of galaxies in space.

Question 75

The height of the quasar epoch was

A) before mass had a chance to accumulate at the nucleus.
B) less than 1 billion years ago.
C) 5 billion years ago.
D) before the formation of galaxies.
E) when there was still sufficient mass to fuel the supermassive black holes at their center.

Question 76

images of galactic clusters reveal large amounts of hot, intracluster gas.

A) Infrared
B) Ultraviolet
C) Radio
D) X- ray
E) Gamma ray

Question 77

The greatest redshifts yet observed for quasars is about

A) 0.1.
B) 0.7.
C) 1.4.
D) 7.0.
E) 14.0.

Question 78

In size and mass, irregular galaxies tend to be than spirals.

Question 79

According to our HST deep surveys, which of the below are NOT less common now than in the early universe?

A) active galaxies
B) elliptical galaxies
C) quasars
D) spiral galaxies
E) irregular galaxies

Question 80

Using binary galaxies to find their masses assumes that, like double stars, their orbits obey laws of Planetary Motion.

A) Einstein's
B) Galileo's
C) Kepler's
D) Schwarzchild's
E) Newton's