Deck 25: Galaxies and Dark Matter: The Large-Scale Structure of the Cosmos

Question 1

Collisions between galaxies have little effect on the individual stars.

Answer 1

True

Question 2

Most large spirals and ellipticals are comparable to the Milky Way in mass.

Answer 2

True

Question 3

Galaxies in clusters are much more likely to become "active" than ones alone in space.

Answer 3

True

Question 4

While quasars may have now vanished,the large black holes they formed are still around,just not being fed as well any more.

Question 5

On average,the stars in elliptical galaxies are older than the stars in spiral galaxies.

Question 6

Vast majority of the known volume of the universe lies in the voids.

Question 7

Dark matter does not affect galaxy collisions.

Question 8

When observing a very distant quasar,we are actually seeing the universe the way it was when it was much younger than it is today.

Question 9

Galaxies contain at most one supermassive black hole.

Question 10

The younger the universe was,the more abundant quasars were,according to our deep surveys.

Question 11

Giant irregulars are the most massive of all known galaxies.

Question 12

Spiral galaxies are much more common in the centers of rich clusters than in the universe as a whole.

Question 13

A large cluster's mass can be over a thousand times that of our Galaxy.

Question 14

The last quasar probably died out a billion years ago,for none lie within a billion light years of us.

Question 15

It is now believed the majority of mass for most galaxies lies in their dark halos.

Question 16

On average,elliptical galaxies are much older than large spiral galaxies.

Question 17

The Lyman-alpha "forest" are absorption lines in a quasar spectrum created by all of the gases along the billions of light years its energy has traversed.

Question 18

For nearby spirals,their rotation curves help measure both light and dark matter.

Question 19

While yet unseen,some gravitational evidence suggests the existence of dark galaxies.

Question 20

Distant galaxies tend to be much bluer than those nearby.

Question 21

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.

Question 22

The distance between adjacent galaxies in a typical cluster is about ________ times the size of a typical galaxy.

A) two or three
B) five or less
C) ten to twenty
D) a hundred
E) a thousand

Question 23

Which of these is NOT considered a fine example of galactic collisions?

A) the Cartwheel Galaxy
B) the Antennae Galaxies
C) the Whirlpool Galaxy
D) M-31 in Andromeda
E) M-87 in Virgo

Question 24

A radio galaxy whose lobes are swept back as if forming a tail.This probably indicates that:

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.

Question 25

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 26

When spiral galaxies do collide,the impact is greatest on their:

A) individual stars.
B) galactic nuclei.
C) giant molecular clouds.
D) open clusters.
E) globular clusters.

Question 27

The largest voids may span 300 million light years across.

Question 28

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 redshifts we now observe.

Question 29

Compared to the Milky Way,how many stars are contained in the most massive galaxies?

A) two to three times as many
B) tens of times as many
C) hundreds of times as many
D) thousands of times as many
E) millions of times as many

Question 30

The type of galaxy where we can track its motion through the intergalactic medium is a:

A) blazar.
B) quasar.
C) pulsar.
D) Head-Tail Radio Galaxy.
E) Seyfert galaxy.

Question 31

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.

Question 32

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.

Question 33

According to their rotation curves,most spiral galaxies:

A) rotate as a solid body.
B) rotate counterclockwise.
C) have decreasing rotational speeds with increasing distance.
D) contain dark matter.
E) contain dark energy.

Question 34

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.

Question 35

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.

Question 36

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.

Question 37

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.

Question 38

Gravity lensing lets us map the distribution of both visible and dark matter.

Question 39

Collisions between galaxies are 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.

Question 40

Due to the galaxy density and collisions,________ are rare in the centers of clusters.

A) irregulars
B) quasars
C) spirals
D) black holes
E) blazars

Question 41

Star streams that are seen around the Milky Way Galaxy are probably the result of:

A) stars ejected from the Galaxy by gravitational encounters with the central black hole.
B) tidal interactions with satellite galaxies.
C) a collision with a large galaxy in the distant past.
D) stars being pulled from the Andromeda Galaxy.
E) spiral density waves.

Question 42

________ galaxies may bridge the gap between spiral galaxies and quasars.

A) Hickson
B) Arp
C) Core-halo
D) Seyfert
E) Hubble

Question 43

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 44

A red supergiant is observed in a globular cluster in another galaxy (located 150,000 light years away).It is predicted,based on its mass and age of the star that it will supernova in about 10,000 years.When will this supernova be visible on Earth?

A) 10,000 years from now
B) 10,000 years ago
C) 150,000 years from now
D) 150,000 years ago
E) 160,000 years from now

Question 45

Why are supermassive galaxies often found at the cores of rich galaxy clusters?

A) Most of the matter forming the cluster fell into the center to form one large galaxy.
B) They are the result of many galactic mergers; one galaxy growing at the expense of others.
C) Such a large galaxy attracted smaller galaxies around it to form a cluster.
D) Large galaxies, passing a cluster, get captured into the center.
E) Many globular clusters swarmed together to form it.

Question 46

A merger between a small elliptical galaxy and a large spiral galaxy will most likely result in:

A) a large elliptical.
B) a large spiral.
C) a small elliptical and a large elliptical.
D) a small elliptical and a large spiral.
E) a small spiral and a large elliptical.

Question 47

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.

Question 48

Active galaxies are having their central engines temporarily fed by what occurrence?

A) a sudden surge in star formation in the nucleus
B) a series of supernovae all occurring in the dense nuclear bulge
C) a close interaction with a neighboring galaxy
D) attack by a swarm of globular clusters
E) the merger of a binary black hole system

Question 49

Redshift 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.

Question 50

Why is it thought that quasars probably spend only a fairly short time in their highly luminous phase?

A) because there aren't many quasars around today
B) because there aren't any quasars closer than about a redshift of 1
C) because all quasars are at about the same epoch, narrowly defined in time
D) because a black hole could not power a highly luminous quasar for more than a few million years
E) because quasars are known to be the consumers of massive galaxies

Question 51

Astronomers think most galaxy interactions took place at redshifts of greater than 1 because:

A) stars were bigger.
B) galaxies were bigger.
C) galaxies were smaller.
D) clusters were more diffuse.
E) clusters were more compact.

Question 52

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.

Question 53

A merger between two large galaxies of comparable size will most likely produce:

A) two small elliptical galaxies.
B) a large elliptical galaxy.
C) a small elliptical galaxy and a small spiral galaxy.
D) a large spiral galaxy.
E) a small elliptical galaxy and a large spiral galaxy.

Question 54

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.

Question 55

An interaction between a large and a small elliptical galaxy that results in a large spiral and a small elliptical galaxy takes:

A) several thousand years.
B) several hundred thousand years.
C) several million years.
D) several hundred million years.
E) several billion years.

Question 56

Some quasars show absorption spectra with a smaller redshift than their emission spectra; this indicates that:

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.

Question 57

What evidence has Chandra found to contradict the hypothesis that black holes merge during galaxy collisions?

A) a double black hole in a single galaxy
B) a black hole without a host galaxy
C) a hypermassive black hole
D) a triple black hole system
E) a dwarf galaxy containing a black hole

Question 58

A billion solar mass black hole has a radius of only:

A) one solar diameter.
B) 20 A.U.
C) 400 A.U.
D) 3 parsecs.
E) 20 parsecs.

Question 59

The further away a galaxy is:

A) the older it is.
B) the further ahead in the future it will exist.
C) the longer ago it existed.
D) the larger it appears.
E) the more massive it is.

Question 60

The peak of the quasar epoch was:

A) when there was still enough dark matter to fuel the supermassive black holes in their bar.
B) when there was still sufficient mass to fuel the supermassive black holes at their center.
C) before the formation of galaxies.
D) before the star formation epoch.
E) before mass had a chance to accumulate at the nucleus.

Question 61

All of the following are clusters of galaxies EXCEPT:

A) Andromeda.
B) Perseus.
C) Coma.
D) Virgo.
E) Hydra.

Question 62

Gas that has never been cycled through a galaxy or a star is said to be ________.

Question 63

Careful observations of nearby normal and active galaxies reveal that the ass of the central black hole is well correlated with the mass of the galactic bulge.The ratio of bulge mass to black hole mass is roughly:

A) 1 to 2000.
B) 1 to 200.
C) 1 to 20.
D) 20 to 1.
E) 200 to 1.

Question 64

The ________ phenomenon is an extremely energetic event which apparently occurs in the nuclei of massive galaxies during an early stage of their evolution.

Question 65

When two galaxies move very closely to each other,their ________ may dramatically rearrange their visible structures.

Question 66

The quasars with the largest presently known redshifts are close to:

A) 0.96.
B) 3.
C) 6.
D) 10.
E) 65.

Question 67

The energy radiated from a typical quasar requires that its black hole accrete about:

A) 1 solar mass per 100 years.
B) 1 solar mass per 10,000 years.
C) 1 Jupiter mass per year.
D) 10 solar masses per year.
E) 1,000 solar masses per year.

Question 68

Infall of ________ may explain the higher than expected star formation rates in galaxies.

Question 69

Giant elliptical galaxies may be the result of ________ in the centers of rich clusters.

Question 70

Voids contain about what percentage of the universe's mass?

A) 0
B) 5-10
C) 40-50
D) 100
E) cannot be determined

Question 71

What is the Great Wall?

A) It is a ridge on the Moon near the crater Birt.
B) It is the distance beyond which astronomers cannot view any more galaxies or even quasars.
C) It is a large sheet of galaxies measuring 70 Mpc by 200 Mpc.
D) It is the time before the universe started expanding, about which we can never know anything.
E) It is an enormous intergalactic cloud of dust and gas that hides more distant galaxies.

Question 72

A supernova that occurs 10,000 years from now in a galaxy 50,000 light years away:

A) will be observed on Earth 10,000 years from now.
B) was observed on Earth 40,000 years ago.
C) will be observed on Earth 40,000 years from now.
D) was observed on Earth 50,000 years ago.
E) will be observed on Earth 50,0000 years from now.

Question 73

Data on binary galaxies is analyzed to determine their average masses under the assumption that they,like binary stars,have ________ orbits.

Question 74

The Sloan Digital Sky Survey uses:

A) a single space-based telescope.
B) a single Earth-based telescope.
C) an array of Earth-based telescopes.
D) several widely distributed Earth-based telescopes.
E) several space-based telescopes.

Question 75

A red supergiant is observed in a globular cluster in another galaxy (located 150,000 light years away).It is predicted,based on its mass and age of the star that it will supernova in about 10,000 years.Is this star still there?

A) No, it died in a supernova 10,000 years ago.
B) No, it died in a supernova 140,000 years ago.
C) No, it died in a supernova 150,000 years ago.
D) Yes, it will die in a supernova in 10,000 years.
E) Yes, it will die in a supernova 160,000 years from now.

Question 76

The lensing of a distant quasar is produced by ________ of a foreground galaxy.

A) all the normal matter and dark matter
B) only the mass of the black hole in the nucleus
C) an individual star
D) a pulsar's intense magnetic field
E) a relativistic jet

Question 77

From studies of the masses of individual galaxies and the masses of clusters of galaxies,it is now apparent that up to ________ of the universe is composed of dark matter.

Question 78

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.

Question 79

A galaxy is at a distance of one billion light years.Which of the following is true?

A) We see the galaxy the way it will be in one billion years.
B) We see the galaxy the way it was one billion years ago.
C) We see the galaxy the way it was when the universe was one billion years old.
D) We see what our galaxy will be like in one billion years.
E) We have no knowledge of anything at that distance.

Question 80

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.