Question 1

Which statement below correctly describes the relationship between expansion rate and age for the universe?

Accepted Answer

A)   The faster the rate of expansion, the younger the age of the universe.
B)   The faster the rate of expansion, the older the age of the universe.
C)   Age is independent of the expansion rate.D) All of the above
E) B) and C)

Question 2

Which of the following types of protogalactic clouds is most likely to form an elliptical galaxy?

Accepted Answer

A)   a very low-density cloud with very little angular momentum
B)   a dense cloud with very little angular momentum
C)   a low-density cloud with quite a bit of angular momentum
D)   a dense cloud with quite a bit of angular momentum
E)   a very massive cloud with any density and a lot of angular momentumF) A) and E)
G) B) and E)

Question 3

Which galaxy, as observed, has aged the most since it was born?

Accepted Answer

A)   A very distant galaxy
B)   A nearby galaxy
C)   The distance of a galaxy doesn't matter.D) A) and B)
E) All of the above

Question 4

What is the major difference between an elliptical galaxy and a spiral galaxy?

Accepted Answer

A)   A spiral galaxy contains mostly younger stars.
B)   A spiral galaxy has a spherical halo.
C)   An elliptical galaxy lacks a disk component.
D)   Elliptical galaxies are not as big as spiral galaxies.
E)   There are no dwarf spiral galaxies, but there are dwarf ellipticals.F) C) and E)
G) C) and D)

Question 5

What evidence tells us that quasars are the centers of distant galaxies?

Accepted Answer

A)   Images and spectra show quasars to be embedded at the centers of distant galaxies.
B)   All quasars have large redshifts.
C)   Quasars are extremely luminous.
D)   Rapid variations in quasar luminosity tell us that they must be quite small in size.E) C) and D)
F) B) and C)

Question 6

The observed relationship between the masses of central black holes and the bulge masses of galaxies implies that:

Accepted Answer

A)   Galaxy formation and supermassive black hole formation must be related somehow.
B)   The black hole will eventually suck in the rest of the galaxy.
C)   The biggest galaxies have the most luminous quasars.
D)   Quasars were more common 10 billion years ago than they are today.E) None of the above
F) B) and C)

Question 7

What is a quasar?

Accepted Answer

A)   a star-like object that actually represents a bright patch of gas in the Milky Way
B)   a very large galaxy thought to be formed by the merger of several smaller galaxies, resulting in a quick burst of star formation
C)   The name given to the largest objects in the Kuiper Belt
D)   the extremely bright center of a distant galaxy, thought to be powered by a supermassive black hole
E)   another name for very bright stars of spectral type OF) None of the above
G) C) and D)

Question 8

Hubble's "constant" is constant in

Accepted Answer

A)   time.
B)   space.
C)   space and time.
D)   our Galaxy, but it is different in others.E) B) and D)
F) A) and B)

Question 9

How does the age of the universe depend on the value of Hubble's constant, and why?

Accepted Answer

A larger value for the Hubble's constant...

Question 10

Why is a dense cloud more likely to produce an elliptical galaxy than a spiral galaxy?

Accepted Answer

A)   The higher density of gas has a stronger force of gravity, and therefore the cloud collapses more quickly.
B)   The force of gravity can pull the material into a more spherical shape.
C)   The more frequent collisions between particles randomize the particle orbits.
D)   The thickness of the dense cloud prevents a disk from forming.
E)   The higher gas density forms stars more efficiently, so all the gas is converted into stars before a disk can form.F) B) and C)
G) C) and E)

Question 11

The distinguishing feature of a starburst galaxy is ________.

Accepted Answer

A)   a rate of star formation that may be 100 or more times greater than that in the Milky Way
B)   the presence of an unusually large number of binary star systems containing X-ray bursters
C)   a very large luminosity compared to the total luminosity of the Milky Way
D)   strong radio emission from "lobes" of material well outside the visible boundaries of the galaxyE) A) and B)
F) A) and C)

Question 12

According to the theory that active galactic nuclei are powered by supermassive black holes, the energy released as light comes from ________.

Accepted Answer

A)   gravitational potential energy released by matter that is falling toward the black hole
B)   nuclear fusion in the accretion disk surrounding the black hole
C)   matter-antimatter annihilation occurring just outside the event horizon of the black hole
D)   jets emerging from the accretion diskE) A) and B)
F) All of the above

Question 13

What is the most accurate way to determine the distance to a nearby galaxy?

Accepted Answer

A)   radar ranging
B)   stellar parallax
C)   main sequence fitting
D)   Cepheid variables
E)   Hubble's lawF) A) and B)
G) None of the above

Question 14

Which of the following types of galaxies appear reddest in color?

Accepted Answer

A)   spirals
B)   ellipticals
C)   lenticulars
D)   irregularsE) None of the above
F) C) and D)

Question 15

Telescopes designed to study the earliest stages in galactic lives should be optimized for observations in ________.

Accepted Answer

A)   infrared light
B)   visible light
C)   radio waves
D)   X-raysE) B) and D)
F) B) and C)

Question 16

Given that white dwarf supernovae are such good standard candles, why don't we use them to measure the distance to all galaxies?

Accepted Answer

A)   They are rare events, so we have observed them in only a tiny fraction of all galaxies.
B)   We cannot see them beyond a distance of about 100 million light-years.
C)   They can occur only in spiral galaxies, not elliptical galaxies.
D)   We would, but we don't have enough telescopes.E) None of the above
F) A) and D)

Question 17

Scale the Milky Way down to the size of a compact disc. Which of the following best describes the size, shape, and distance of the Andromeda Galaxy on the same scale?

Accepted Answer

A)   a compact disk a few meters away
B)   a grapefruit a few meters away
C)   a compact disk about the length of a football field away
D)   a pecan nut about 1 centimeter away
E)   a grapefruit about 1 kilometer awayF) C) and D)
G) B) and E)

Question 18

A quasar's spectrum is hugely redshifted. What does this large redshift tells us about the quasar?

Accepted Answer

A)   The composition of the quasar
B)   The distance to the quasar
C)   The size of the quasar's central, supermassive black hole
D)   The type of host galaxy in which the quasar residesE) A) and B)
F) C) and D)

Question 19

What does Hubble's law tell us?

Accepted Answer

A)   The more distant a galaxy, the faster it is moving away from us.
B)   The faster a spiral galaxy's rotation speed, the more luminous it is.
C)   The longer the period of a Cepheid variable, the greater its luminosity.
D)   For every force, there is an equal and opposite reaction force.E) B) and C)
F) A) and D)

Question 20

The most basic difference between elliptical galaxies and spiral galaxies is that ________.

Accepted Answer

A)   elliptical galaxies lack anything resembling the disk of a spiral galaxy
B)   elliptical galaxies lack anything resembling the halo of a spiral galaxy
C)   elliptical galaxies have a spheroidal component (of stars distributed spherically about the galactic center) , and spiral galaxies do not
D)   elliptical galaxies are very old and spiral galaxies are very youngE) A) and B)
F) None of the above

Exam 15: Galaxies and the Foundation of Modern Cosmology

Why is a dense cloud more likely to produce an elliptical galaxy than a spiral galaxy?

Correct AnswerverifiedShow Answer

Telescopes designed to study the earliest stages in galactic lives should be optimized for observations in ________.

Correct AnswerverifiedShow Answer

Which galaxy, as observed, has aged the most since it was born?

Correct AnswerverifiedShow Answer

Scale the Milky Way down to the size of a compact disc. Which of the following best describes the size, shape, and distance of the Andromeda Galaxy on the same scale?

Correct AnswerverifiedShow Answer

The most basic difference between elliptical galaxies and spiral galaxies is that ________.

Correct AnswerverifiedShow Answer

What is the major difference between an elliptical galaxy and a spiral galaxy?

Correct AnswerverifiedShow Answer

A quasar's spectrum is hugely redshifted. What does this large redshift tells us about the quasar?

Correct AnswerverifiedShow Answer

What does Hubble's law tell us?

Correct AnswerverifiedShow Answer

According to the theory that active galactic nuclei are powered by supermassive black holes, the energy released as light comes from ________.

Correct AnswerverifiedShow Answer

The observed relationship between the masses of central black holes and the bulge masses of galaxies implies that:

Correct AnswerverifiedShow Answer

Given that white dwarf supernovae are such good standard candles, why don't we use them to measure the distance to all galaxies?

Correct AnswerverifiedShow Answer

What evidence tells us that quasars are the centers of distant galaxies?

Correct AnswerverifiedShow Answer

The distinguishing feature of a starburst galaxy is ________.

Correct AnswerverifiedShow Answer

How does the age of the universe depend on the value of Hubble's constant, and why?

Correct AnswerverifiedA larger value for the Hubble's constant...View AnswerShow Answer

Which statement below correctly describes the relationship between expansion rate and age for the universe?

Correct AnswerverifiedShow Answer

Which of the following types of protogalactic clouds is most likely to form an elliptical galaxy?

Correct AnswerverifiedShow Answer

Hubble's "constant" is constant in

Correct AnswerverifiedShow Answer

Which of the following types of galaxies appear reddest in color?

Correct AnswerverifiedShow Answer

What is the most accurate way to determine the distance to a nearby galaxy?

Correct AnswerverifiedShow Answer

What is a quasar?

Correct AnswerverifiedShow Answer

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A larger value for the Hubble's constant...
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