Question 1

The one component of the material of the Milky Way Galaxy that prevents us from seeing and photographing the galactic center at optical wavelengths is:

Accepted Answer

A)  very cold hydrogen gas. 
B)  interstellar dust. 
C)  the glare of light from nearby stars. 
D)  hot hydrogen gas. 
A)  very cold hydrogen gas. 
B)  interstellar dust. 
C)  the glare of light from nearby stars. 
D)  hot hydrogen gas.

Question 2

The extreme redshifts of quasar spectra are caused by:

Accepted Answer

A)  very high recession speeds of the sources away from the Milky Way Galaxy. 
B)  absorption of all but the red parts of the quasar spectrum by intergalactic matter. 
C)  Zeeman effects from the very intense magnetic fields in the vicinity of the source. 
D)  high gravitational fields at the surfaces of the quasars (gravitational redshift). 
A)  very high recession speeds of the sources away from the Milky Way Galaxy. 
B)  absorption of all but the red parts of the quasar spectrum by intergalactic matter. 
C)  Zeeman effects from the very intense magnetic fields in the vicinity of the source. 
D)  high gravitational fields at the surfaces of the quasars (gravitational redshift).

Question 3

Recent evidence suggests that galaxies formed:

Accepted Answer

A)  from the collapse of immense clouds of gas and dust. 
B)  from the mergers of hundreds of smaller objects. 
C)  when primordial clouds of dark matter dispersed and broke apart. 
D)  as direct, immediate products of the Big Bang. 
A)  from the collapse of immense clouds of gas and dust. 
B)  from the mergers of hundreds of smaller objects. 
C)  when primordial clouds of dark matter dispersed and broke apart. 
D)  as direct, immediate products of the Big Bang.

Question 4

The stars in the Milky Way Galaxy:

Accepted Answer

A)  obey Hubble's law of recession. 
B)  are all receding from the galactic center. 
C)  move generally around the galactic center. 
D)  number between 8 and 10 million. 
A)  obey Hubble's law of recession. 
B)  are all receding from the galactic center. 
C)  move generally around the galactic center. 
D)  number between 8 and 10 million.

Question 5

When we look out into the plane of the Milky Way Galaxy,how far can we see?

Accepted Answer

A)  infinitely far 
B)  about 100,000 ly 
C)  less than 1000 ly 
D)  about 10,000 ly 
A)  infinitely far 
B)  about 100,000 ly 
C)  less than 1000 ly 
D)  about 10,000 ly

Question 6

How many stars per cubic parsec are there in the spiral arms of a spiral galaxy compared with the regions between the spiral arms?

Accepted Answer

A)  There are more than 100 times as many stars in the spiral arms as there are in the regions between the arms. 
B)  There are about twice as many stars in the spiral arms than in the regions between the arms. 
C)  There are a lot of stars in the spiral arms and none at all in the regions between the arms. 
D)  There are about 5% more stars in the spiral arms than in the regions between the arms. 
A)  There are more than 100 times as many stars in the spiral arms as there are in the regions between the arms. 
B)  There are about twice as many stars in the spiral arms than in the regions between the arms. 
C)  There are a lot of stars in the spiral arms and none at all in the regions between the arms. 
D)  There are about 5% more stars in the spiral arms than in the regions between the arms.

Question 7

How far away from us is the Andromeda Galaxy compared with the diameter of the Milky Way Galaxy?

Accepted Answer

A)  The Andromeda Galaxy is about three Milky Way diameters away. 
B)  The Andromeda Galaxy is about 20 Milky Way diameters away. 
C)  The Andromeda Galaxy is between 100 and 120 Milky Way diameters away. 
D)  The Andromeda Galaxy is several million Milky Way diameters away. 
A)  The Andromeda Galaxy is about three Milky Way diameters away. 
B)  The Andromeda Galaxy is about 20 Milky Way diameters away. 
C)  The Andromeda Galaxy is between 100 and 120 Milky Way diameters away. 
D)  The Andromeda Galaxy is several million Milky Way diameters away.

Question 8

Distances to a nearby galaxy can be determined MOST accurately by:

Accepted Answer

A)  using pulsating stars as beacons. 
B)  measuring the chemical compositions of the brightest stars. 
C)  measuring the shifts of spectral lines from the Milky Way Galaxy. 
D)  measuring the total amount of energy received from the Milky Way Galaxy. 
A)  using pulsating stars as beacons. 
B)  measuring the chemical compositions of the brightest stars. 
C)  measuring the shifts of spectral lines from the Milky Way Galaxy. 
D)  measuring the total amount of energy received from the Milky Way Galaxy.

Question 9

The major surprise about Cygnus A,one of the first three sources of strong radio emission detected by Grote Reber in the late 1930s,when examined with large optical telescopes,was that it:

Accepted Answer

A)  had no corresponding optical counterpart at all. 
B)  was at the center of the Milky Way Galaxy. 
C)  was a very distant object that was relatively faint at optical wavelengths yet extremely luminous at radio wavelengths. 
D)  was a very bright supernova remnant. 
A)  had no corresponding optical counterpart at all. 
B)  was at the center of the Milky Way Galaxy. 
C)  was a very distant object that was relatively faint at optical wavelengths yet extremely luminous at radio wavelengths. 
D)  was a very bright supernova remnant.

Question 10

How do we obtain an estimate of the amount of mass that is inside the Sun's orbital path in the Milky Way Galaxy?

Accepted Answer

A)  by counting stars, assuming an average stellar mass, and calculating the total mass 
B)  by observing the bending of light from distant galaxies as the light passes near the center of the Milky Way 
C)  by observing the movement of the Galaxy toward neighboring galaxies because of mutual gravitational attraction 
D)  by applying Kepler's law to the motion of the Sun and other nearby stars 
A)  by counting stars, assuming an average stellar mass, and calculating the total mass 
B)  by observing the bending of light from distant galaxies as the light passes near the center of the Milky Way 
C)  by observing the movement of the Galaxy toward neighboring galaxies because of mutual gravitational attraction 
D)  by applying Kepler's law to the motion of the Sun and other nearby stars

Question 11

The Tully-Fisher relation can be used to determine the distance to:

Accepted Answer

A)  spiral galaxies only. 
B)  elliptical galaxies only. 
C)  irregular galaxies only. 
D)  either spirals or ellipticals. 
A)  spiral galaxies only. 
B)  elliptical galaxies only. 
C)  irregular galaxies only. 
D)  either spirals or ellipticals.

Question 12

The typical timescale for variability of a blazar (a parameter related to true physical size of these objects)is:

Accepted Answer

A)  about 1 week. 
B)  less than 1 day. 
C)  a few seconds. 
D)  about 1 year. 
A)  about 1 week. 
B)  less than 1 day. 
C)  a few seconds. 
D)  about 1 year.

Question 13

Why is the Coma cluster of galaxies a favorite among astronomers?

Accepted Answer

A)  The Coma cluster is the cluster in which the Milky Way Galaxy is situated. 
B)  The Coma cluster contains two quasars. 
C)  The Coma cluster is the rich, regular cluster nearest Earth. 
D)  The Coma cluster is the rich, irregular cluster nearest Earth. 
A)  The Coma cluster is the cluster in which the Milky Way Galaxy is situated. 
B)  The Coma cluster contains two quasars. 
C)  The Coma cluster is the rich, regular cluster nearest Earth. 
D)  The Coma cluster is the rich, irregular cluster nearest Earth.

Question 14

The twentieth century opened with a major unresolved question among astronomers.This was the subject of the famous Shapley-Curtis debate.What was this question?

Accepted Answer

A)  How old is the Milky Way Galaxy? 
B)  What is the nature of dark matter? 
C)  Is general relativity true? 
D)  Is the Milky Way Galaxy the whole universe, or only one of many galaxies? 
A)  How old is the Milky Way Galaxy? 
B)  What is the nature of dark matter? 
C)  Is general relativity true? 
D)  Is the Milky Way Galaxy the whole universe, or only one of many galaxies?

Question 15

Which concept concerning the diffuse objects observed by Herschel was proposed by Kant in the 1700s and was strongly supported by observations made in 1845 by the Earl of Rosse with his world-class telescope in Ireland?

Accepted Answer

A)  Many of the diffuse objects in Earth's sky are moving rapidly away from the Milky Way Galaxy. 
B)  Many of the nebulae in the sky are separate entities beyond the Milky Way Galaxy. 
C)  The diffuse objects observed by Herschel and known as planetary nebulae were in fact planets orbiting other stars in the Milky Way Galaxy. 
D)  All the diffuse nebulae seen in the sky are gas clouds in the Milky Way Galaxy. 
A)  Many of the diffuse objects in Earth's sky are moving rapidly away from the Milky Way Galaxy. 
B)  Many of the nebulae in the sky are separate entities beyond the Milky Way Galaxy. 
C)  The diffuse objects observed by Herschel and known as planetary nebulae were in fact planets orbiting other stars in the Milky Way Galaxy. 
D)  All the diffuse nebulae seen in the sky are gas clouds in the Milky Way Galaxy.

Question 16

Suppose the X-ray signal from a quasar fluctuates with a period of three hours.What is the MAXIMUM size of the source?

Accepted Answer

A)  150,000 km, about the diameter of Jupiter 
B)  10.8 AU, about the diameter of Jupiter's orbit 
C)  4.5 ly, about the distance between the Sun and the nearest star 
D)  10,800 ly, one-tenth the size of the Milky Way Galaxy 
A)  150,000 km, about the diameter of Jupiter 
B)  10.8 AU, about the diameter of Jupiter's orbit 
C)  4.5 ly, about the distance between the Sun and the nearest star 
D)  10,800 ly, one-tenth the size of the Milky Way Galaxy

Question 17

In the unified model of active galaxies,the main difference among quasars,BL Lacertae objects,and radio galaxies appears to be that:

Accepted Answer

A)  we see the accretion disk around the central black hole from a different angle in each case-face-on for BL Lacertae, edge-on for radio galaxies, and in between for quasars. 
B)  the rate at which matter is falling into the central black hole is different in each case-largest in quasars, less in BL Lacertae objects, and least in radio galaxies. 
C)  the mass of the central black hole is different in each case-largest in quasars, less in BL Lacertae, and least in radio galaxies. 
D)  the galaxy type with which they are associated is different in each case-spiral for BL Lacertae, elliptical for quasars, and irregular for radio galaxies. 
A)  we see the accretion disk around the central black hole from a different angle in each case-face-on for BL Lacertae, edge-on for radio galaxies, and in between for quasars. 
B)  the rate at which matter is falling into the central black hole is different in each case-largest in quasars, less in BL Lacertae objects, and least in radio galaxies. 
C)  the mass of the central black hole is different in each case-largest in quasars, less in BL Lacertae, and least in radio galaxies. 
D)  the galaxy type with which they are associated is different in each case-spiral for BL Lacertae, elliptical for quasars, and irregular for radio galaxies.

Question 18

What has microlensing told us about the role of brown dwarfs in the Milky Way Galaxy?

Accepted Answer

A)  Brown dwarfs cannot be a major component of the dark matter in the Galaxy. 
B)  Brown dwarfs are a major component of the matter that is falling into the supermassive black hole in the galactic center. 
C)  Brown dwarfs are one of the most important components of the Galaxy's dark matter. 
D)  Microlensing has told us almost nothing yet about brown dwarfs-microlensing is too difficult to observe. 
A)  Brown dwarfs cannot be a major component of the dark matter in the Galaxy. 
B)  Brown dwarfs are a major component of the matter that is falling into the supermassive black hole in the galactic center. 
C)  Brown dwarfs are one of the most important components of the Galaxy's dark matter. 
D)  Microlensing has told us almost nothing yet about brown dwarfs-microlensing is too difficult to observe.

Question 19

How are galaxies spread throughout the universe?

Accepted Answer

A)  Galaxies are densest near the Milky Way Galaxy and become less and less numerous the farther we look out into the universe. 
B)  Galaxies are grouped in clusters that are spread more or less evenly throughout the universe. 
C)  Galaxies are spread more or less evenly throughout the universe. 
D)  Clusters of galaxies exist that are themselves often clustered into superclusters. Clusters and superclusters appear to be distributed on surfaces surrounding empty regions of space. 
A)  Galaxies are densest near the Milky Way Galaxy and become less and less numerous the farther we look out into the universe. 
B)  Galaxies are grouped in clusters that are spread more or less evenly throughout the universe. 
C)  Galaxies are spread more or less evenly throughout the universe. 
D)  Clusters of galaxies exist that are themselves often clustered into superclusters. Clusters and superclusters appear to be distributed on surfaces surrounding empty regions of space.

Question 20

In the self-propagating star formation theory:

Accepted Answer

A)  spiral arms are formed and sustained primarily by the actions of solar-mass stars because there are so many more of them than there are high-mass stars. 
B)  spiral arms are poorly defined because they are formed and sustained primarily by the actions of short-lived massive stars. 
C)  the passage of dust clouds through the spiral arms triggers star formation. 
D)  spiral structure results with thin, well-defined arms. 
A)  spiral arms are formed and sustained primarily by the actions of solar-mass stars because there are so many more of them than there are high-mass stars. 
B)  spiral arms are poorly defined because they are formed and sustained primarily by the actions of short-lived massive stars. 
C)  the passage of dust clouds through the spiral arms triggers star formation. 
D)  spiral structure results with thin, well-defined arms.

The one component of the material of the Milky Way Galaxy that prevents us from seeing and photographing the galactic center at optical wavelengths is:

The extreme redshifts of quasar spectra are caused by:

Recent evidence suggests that galaxies formed:

The stars in the Milky Way Galaxy:

When we look out into the plane of the Milky Way Galaxy,how far can we see?

How many stars per cubic parsec are there in the spiral arms of a spiral galaxy compared with the regions between the spiral arms?

How far away from us is the Andromeda Galaxy compared with the diameter of the Milky Way Galaxy?

Distances to a nearby galaxy can be determined MOST accurately by:

The major surprise about Cygnus A,one of the first three sources of strong radio emission detected by Grote Reber in the late 1930s,when examined with large optical telescopes,was that it:

How do we obtain an estimate of the amount of mass that is inside the Sun's orbital path in the Milky Way Galaxy?

The Tully-Fisher relation can be used to determine the distance to:

The typical timescale for variability of a blazar (a parameter related to true physical size of these objects)is:

Why is the Coma cluster of galaxies a favorite among astronomers?

The twentieth century opened with a major unresolved question among astronomers.This was the subject of the famous Shapley-Curtis debate.What was this question?

Which concept concerning the diffuse objects observed by Herschel was proposed by Kant in the 1700s and was strongly supported by observations made in 1845 by the Earl of Rosse with his world-class telescope in Ireland?

Suppose the X-ray signal from a quasar fluctuates with a period of three hours.What is the MAXIMUM size of the source?

In the unified model of active galaxies,the main difference among quasars,BL Lacertae objects,and radio galaxies appears to be that:

What has microlensing told us about the role of brown dwarfs in the Milky Way Galaxy?

How are galaxies spread throughout the universe?

In the self-propagating star formation theory:

Discovering the Night Sky

Gravitation and the Waltz of the Planets

Light and Telescopes

Formation of the Solar System and Other Planetary Systems

Exoplanets

The Terrestrial Planets and Their Moons

The Outer Planets and Their Moons

Vagabonds of the Solar System

The Sun: Our Extraordinary Ordinary Star

Characterizing Stars

The Lives of the Stars From Birth Through Middle Age

The Deaths and Remnants of Stars

Cosmology

Astrobiology

Filters

Exam 13: The Galaxies

The one component of the material of the Milky Way Galaxy that prevents us from seeing and photographing the galactic center at optical wavelengths is:

The extreme redshifts of quasar spectra are caused by:

Recent evidence suggests that galaxies formed:

The stars in the Milky Way Galaxy:

When we look out into the plane of the Milky Way Galaxy,how far can we see?

How many stars per cubic parsec are there in the spiral arms of a spiral galaxy compared with the regions between the spiral arms?

How far away from us is the Andromeda Galaxy compared with the diameter of the Milky Way Galaxy?

Distances to a nearby galaxy can be determined MOST accurately by:

The major surprise about Cygnus A,one of the first three sources of strong radio emission detected by Grote Reber in the late 1930s,when examined with large optical telescopes,was that it:

How do we obtain an estimate of the amount of mass that is inside the Sun's orbital path in the Milky Way Galaxy?

The Tully-Fisher relation can be used to determine the distance to:

The typical timescale for variability of a blazar (a parameter related to true physical size of these objects)is:

Why is the Coma cluster of galaxies a favorite among astronomers?

The twentieth century opened with a major unresolved question among astronomers.This was the subject of the famous Shapley-Curtis debate.What was this question?

Which concept concerning the diffuse objects observed by Herschel was proposed by Kant in the 1700s and was strongly supported by observations made in 1845 by the Earl of Rosse with his world-class telescope in Ireland?

Suppose the X-ray signal from a quasar fluctuates with a period of three hours.What is the MAXIMUM size of the source?

In the unified model of active galaxies,the main difference among quasars,BL Lacertae objects,and radio galaxies appears to be that:

What has microlensing told us about the role of brown dwarfs in the Milky Way Galaxy?

How are galaxies spread throughout the universe?

In the self-propagating star formation theory:

Discovering the Night Sky

Gravitation and the Waltz of the Planets

Light and Telescopes

Formation of the Solar System and Other Planetary Systems

Exoplanets

The Terrestrial Planets and Their Moons

The Outer Planets and Their Moons

Vagabonds of the Solar System

The Sun: Our Extraordinary Ordinary Star

Characterizing Stars

The Lives of the Stars From Birth Through Middle Age

The Deaths and Remnants of Stars

Cosmology

Astrobiology

Filters