Question 1

What evidence do we have that large galaxies cannibalize small galaxies?

Accepted Answer

The answer of What evidence do we have that large...

Question 2

If a quasar has a redshift of 0.98, then it is receding from Earth at 98 percent the speed of light.

Accepted Answer

A) True 
 B)False

Question 3

The total mass of galaxies in a cluster of galaxies divided by the number of galaxies in the cluster can be used to determine a typical galaxy's ____

Accepted Answer

A)  luminosity. 
B)  distance. 
C)  mass. 
D)  diameter. 
E)  age. 
A)  luminosity. 
B)  distance. 
C)  mass. 
D)  diameter. 
E)  age.

Question 4

When two galaxies collide, they pass through each other and their stars almost never collide.

Accepted Answer

A) True 
 B)False

Question 5

The Milky Way is part of

Accepted Answer

A)  I and III 
B)  I and IV 
C)  II and III 
D)  II and IV 
E)  just III 
A)  I and III 
B)  I and IV 
C)  II and III 
D)  II and IV 
E)  just III

Question 6

The Hubble law is a relation between a galaxy's

Accepted Answer

A)  mass and its luminosity. 
B)  distance and its luminosity. 
C)  mass and its recession velocity. 
D)  distance and its recession velocity. 
E)  mass and its diameter. 
A)  mass and its luminosity. 
B)  distance and its luminosity. 
C)  mass and its recession velocity. 
D)  distance and its recession velocity. 
E)  mass and its diameter.

Question 7

A quasar's redshift and apparent magnitude lead us to believe that it is very luminous. What assumptions do we make in reaching this conclusion?

Accepted Answer

To conclude that a quasar is very lumino

Question 8

The discovery of the gravitational lens effect for quasars

Accepted Answer

A)  shows that quasars were located within the local group of galaxies. 
B)  shows that quasars were giant planets in our solar system. 
C)  shows that quasars are much further away than the distant galaxy that forms the gravitational lens. 
D)  proves Newton's theory of gravitation by showing that the photon is affected by gravity. 
E)  proves the existence of supermassive black holes at the center of active galactic nuclei. 
A)  shows that quasars were located within the local group of galaxies. 
B)  shows that quasars were giant planets in our solar system. 
C)  shows that quasars are much further away than the distant galaxy that forms the gravitational lens. 
D)  proves Newton's theory of gravitation by showing that the photon is affected by gravity. 
E)  proves the existence of supermassive black holes at the center of active galactic nuclei.

Question 9

Propose a hypothesis to explain why rich galaxy clusters have a larger proportion of elliptical and S0 galaxies than other galaxy clusters.

Accepted Answer

One hypothesis to explain why rich galax

Question 10

How are astronomers able to determine that quasars are so small?

Accepted Answer

A)  They are variable over a short period of time. 
B)  They emit mainly X-rays. 
C)  They are only found at very large distance. 
D)  The structure of a quasar is completely resolved in images. 
A)  They are variable over a short period of time. 
B)  They emit mainly X-rays. 
C)  They are only found at very large distance. 
D)  The structure of a quasar is completely resolved in images.

Question 11

An elliptical (E) galaxy contains

Accepted Answer

A)  mostly lower-main-sequence stars and giants. 
B)  mostly upper-main-sequence stars and giants. 
C)  mostly upper-main-sequence stars and gas and dust. 
D)  roughly equal numbers of upper- and lower-main-sequence stars. 
E)  mostly white dwarfs and supergiants. 
A)  mostly lower-main-sequence stars and giants. 
B)  mostly upper-main-sequence stars and giants. 
C)  mostly upper-main-sequence stars and gas and dust. 
D)  roughly equal numbers of upper- and lower-main-sequence stars. 
E)  mostly white dwarfs and supergiants.

Question 12

A megaparsec is equivalent to

Accepted Answer

A)  3.26 light-years. 
B)  206,265 AU. 
C)  the age of our solar system. 
D)  a million parsecs. 
E)  the diameter of the Milky Way galaxy. 
A)  3.26 light-years. 
B)  206,265 AU. 
C)  the age of our solar system. 
D)  a million parsecs. 
E)  the diameter of the Milky Way galaxy.

Question 13

Astronomers who discovered quasars found that they show ________ of their spectral lines and are thus probably much ________ than nearby galaxies.

Accepted Answer

A)  large redshifts; farther away 
B)  large blueshifts; farther away 
C)  no wavelength difference; nearer 
D)  large redshifts; nearer 
E)  large blueshift; nearer 
A)  large redshifts; farther away 
B)  large blueshifts; farther away 
C)  no wavelength difference; nearer 
D)  large redshifts; nearer 
E)  large blueshift; nearer

Question 14

Centaurus A is a radio galaxy that has a visible galaxy at the center. This central elliptical galaxy of Centaurus A is encircled by a ring of gas and dust, different from most elliptical galaxies. The dust ring orbits about an axis that is perpendicular to the axis of rotation of the elliptical galaxy. What does this suggest about this central elliptical galaxy of Centaurus A?

Accepted Answer

A)  The radio jets have caused the dust disk to be driven around the elliptical galaxy. 
B)  There are at least two black holes at the center of the elliptical galaxy. 
C)  Centaurus A is probably the result of a merger of an elliptical galaxy and a spiral galaxy. 
D)  Dust is produced as the jets interact with the intergalactic medium. 
E)  Elliptical galaxies often contain dust that forms a disk along their rotation axis. 
A)  The radio jets have caused the dust disk to be driven around the elliptical galaxy. 
B)  There are at least two black holes at the center of the elliptical galaxy. 
C)  Centaurus A is probably the result of a merger of an elliptical galaxy and a spiral galaxy. 
D)  Dust is produced as the jets interact with the intergalactic medium. 
E)  Elliptical galaxies often contain dust that forms a disk along their rotation axis.

Question 15

The rapid fluctuations of quasars show that the energy emitting portions of these objects must be very small.

Accepted Answer

A) True 
 B)False

Question 16

_____ galaxies contain a supermassive black hole at their centers while active nuclei are present in _____of galaxies

Accepted Answer

A)  Most; a few percent 
B)  Most; the majority 
C)  A small minority; a few percent 
D)  A small minority; the majority 
A)  Most; a few percent 
B)  Most; the majority 
C)  A small minority; a few percent 
D)  A small minority; the majority

Question 17

The figure shows an image of our galaxy, the Milky Way, at dust-penetrating wavelengths. It can be classified as which one of the following galactic types?

Accepted Answer

A)  spiral 
B)  irregular 
C)  elliptical 
D)  red giant 
A)  spiral 
B)  irregular 
C)  elliptical 
D)  red giant

Question 18

Measuring the Doppler shift of material at various distances from the center of a galaxy can be used to construct a(n) ____________________ for that galaxy.

Accepted Answer

The answer of Measuring the Doppler shift of material at...

Question 19

How do astronomers know that the luminous regions of active nuclei of active galaxies are very small?

Accepted Answer

A)  Their nuclei are much brighter than expected. 
B)  The orbits of stars near the center of the galactic nuclei are faster than expected. 
C)  The luminosity of the nuclei varies over short times. 
D)  The color of the nuclei is different than expected. 
A)  Their nuclei are much brighter than expected. 
B)  The orbits of stars near the center of the galactic nuclei are faster than expected. 
C)  The luminosity of the nuclei varies over short times. 
D)  The color of the nuclei is different than expected.

Question 20

Why do astronomers believe supermassive black holes are the source of an AGN's energy?

Accepted Answer

A)  Such black holes have been found at the center of most galaxies, both active and inactive. 
B)  Radio jets are seen from low-mass black holes plus accretion disks inside our galaxy. 
C)  Jets and accretion disks have been observed in active galaxies. 
D)  Black holes can produce so much energy in such a small place. 
E)  all of the above 
A)  Such black holes have been found at the center of most galaxies, both active and inactive. 
B)  Radio jets are seen from low-mass black holes plus accretion disks inside our galaxy. 
C)  Jets and accretion disks have been observed in active galaxies. 
D)  Black holes can produce so much energy in such a small place. 
E)  all of the above

What evidence do we have that large galaxies cannibalize small galaxies?

If a quasar has a redshift of 0.98, then it is receding from Earth at 98 percent the speed of light.

The total mass of galaxies in a cluster of galaxies divided by the number of galaxies in the cluster can be used to determine a typical galaxy's ____

When two galaxies collide, they pass through each other and their stars almost never collide.

The Milky Way is part of

The Hubble law is a relation between a galaxy's

A quasar's redshift and apparent magnitude lead us to believe that it is very luminous. What assumptions do we make in reaching this conclusion?

The discovery of the gravitational lens effect for quasars

Propose a hypothesis to explain why rich galaxy clusters have a larger proportion of elliptical and S0 galaxies than other galaxy clusters.

How are astronomers able to determine that quasars are so small?

An elliptical (E) galaxy contains

A megaparsec is equivalent to

Astronomers who discovered quasars found that they show of their spectral lines and are thus probably much than nearby galaxies.

The rapid fluctuations of quasars show that the energy emitting portions of these objects must be very small.

_ galaxies contain a supermassive black hole at their centers while active nuclei are present in _of galaxies

The figure shows an image of our galaxy, the Milky Way, at dust-penetrating wavelengths. It can be classified as which one of the following galactic types?

Measuring the Doppler shift of material at various distances from the center of a galaxy can be used to construct a(n) ____________________ for that galaxy.

How do astronomers know that the luminous regions of active nuclei of active galaxies are very small?

Why do astronomers believe supermassive black holes are the source of an AGN's energy?

Here and Now

A Users Guide to the Sky

Cycles of the Sun and Moon

The Origin of Modern Astronomy

Light and Telescopes

Atoms and Spectra

The Sun

The Family of Stars

The Formation and Structure of Stars

The Deaths of Stars

Neutron Stars and Black Holes

The Milky Way Galaxy

Modern Cosmology

The Origin of the Solar System

Earth and Moon: Bases for Comparative Planetology

Mercury, Venus and Mars

The Outer Solar System

Meteorites, Asteroids, and Comets

Astrobiology: Life on Other Worlds

Filters

Exam 13: Galaxies: Normal and Active

What evidence do we have that large galaxies cannibalize small galaxies?

If a quasar has a redshift of 0.98, then it is receding from Earth at 98 percent the speed of light.

The total mass of galaxies in a cluster of galaxies divided by the number of galaxies in the cluster can be used to determine a typical galaxy's ____

When two galaxies collide, they pass through each other and their stars almost never collide.

The Milky Way is part of

The Hubble law is a relation between a galaxy's

A quasar's redshift and apparent magnitude lead us to believe that it is very luminous. What assumptions do we make in reaching this conclusion?

The discovery of the gravitational lens effect for quasars

Propose a hypothesis to explain why rich galaxy clusters have a larger proportion of elliptical and S0 galaxies than other galaxy clusters.

How are astronomers able to determine that quasars are so small?

An elliptical (E) galaxy contains

A megaparsec is equivalent to

Astronomers who discovered quasars found that they show ________ of their spectral lines and are thus probably much ________ than nearby galaxies.

The rapid fluctuations of quasars show that the energy emitting portions of these objects must be very small.

_____ galaxies contain a supermassive black hole at their centers while active nuclei are present in _____of galaxies

The figure shows an image of our galaxy, the Milky Way, at dust-penetrating wavelengths. It can be classified as which one of the following galactic types?

Measuring the Doppler shift of material at various distances from the center of a galaxy can be used to construct a(n) ____________________ for that galaxy.

How do astronomers know that the luminous regions of active nuclei of active galaxies are very small?

Why do astronomers believe supermassive black holes are the source of an AGN's energy?

Here and Now

A Users Guide to the Sky

Cycles of the Sun and Moon

The Origin of Modern Astronomy

Light and Telescopes

Atoms and Spectra

The Sun

The Family of Stars

The Formation and Structure of Stars

The Deaths of Stars

Neutron Stars and Black Holes

The Milky Way Galaxy

Modern Cosmology

The Origin of the Solar System

Earth and Moon: Bases for Comparative Planetology

Mercury, Venus and Mars

The Outer Solar System

Meteorites, Asteroids, and Comets

Astrobiology: Life on Other Worlds

Filters

Astronomers who discovered quasars found that they show of their spectral lines and are thus probably much than nearby galaxies.

_ galaxies contain a supermassive black hole at their centers while active nuclei are present in _of galaxies