Question 1

Synchrotron radiation is produced whenever:

Accepted Answer

A)  electrons jump from level to level in an atom. 
B)  electrons are accelerated as they circle in spirals in a magnetic field. 
C)  atoms in a molecule vibrate back and forth. 
D)  electrons move in a transparent medium at a speed faster than the speed of light in the medium. 
A)  electrons jump from level to level in an atom. 
B)  electrons are accelerated as they circle in spirals in a magnetic field. 
C)  atoms in a molecule vibrate back and forth. 
D)  electrons move in a transparent medium at a speed faster than the speed of light in the medium.

Question 2

The supermassive black hole at the center of our Milky Way Galaxy has a diameter of approximately 8 × 10-⁷ pc and is approximately 8000 pc away from us.Figure 13-13b of Discovering the Essential Universe,6th ed.,shows a drawing of the center of the galaxy with a size indicator showing 0.2 arcseconds.How does the angular size of the block hole compare to this?

Accepted Answer

A)  It is about 2 × 10⁵ arcseconds - too large to fit in the figure. 
B)  It is just about 0.2 arcseconds. 
C)  It is 1.25 × 10-⁴ which just might just show up on the scale of this figure. 
D)  It is about 2 × 10-⁵ arcseconds-too small to show up on the scale of this figure. 
A)  It is about 2 × 10⁵ arcseconds - too large to fit in the figure. 
B)  It is just about 0.2 arcseconds. 
C)  It is 1.25 × 10-⁴ which just might just show up on the scale of this figure. 
D)  It is about 2 × 10-⁵ arcseconds-too small to show up on the scale of this figure.

Question 3

The observational fact about a Cepheid variable star that leads to a measurement of its distance from us is that its period of variation is directly related to its:

Accepted Answer

A)  surface temperature. 
B)  position along the spiral arms of a galaxy. 
C)  apparent magnitude. 
D)  absolute magnitude. 
A)  surface temperature. 
B)  position along the spiral arms of a galaxy. 
C)  apparent magnitude. 
D)  absolute magnitude.

Question 4

The first three strong radio sources,discovered by Reber in the 1930s and 1940s,did NOT include a:

Accepted Answer

A)  galactic nucleus. 
B)  supernova remnant. 
C)  globular cluster. 
D)  distant galaxy. 
A)  galactic nucleus. 
B)  supernova remnant. 
C)  globular cluster. 
D)  distant galaxy.

Question 5

Which characteristic does the Local Group of galaxies NOT have?

Accepted Answer

A)  poor cluster 
B)  irregular cluster 
C)  domination by a central giant elliptical 
D)  several large spirals 
A)  poor cluster 
B)  irregular cluster 
C)  domination by a central giant elliptical 
D)  several large spirals

Question 6

The mechanism that leads to the double-radio source phenomenon appears to be:

Accepted Answer

A)  two active galaxies in orbit around a common center, like a binary star system. 
B)  two oppositely directed jets of energetic particles from an active galactic object colliding with other intergalactic material. 
C)  a radio-bright galaxy crossed by a dark, absorbing, edge-on disk, splitting the radio emissions into two as seen from Earth. 
D)  gravitational lensing of a distant radio source by a nearby galaxy or black hole. 
A)  two active galaxies in orbit around a common center, like a binary star system. 
B)  two oppositely directed jets of energetic particles from an active galactic object colliding with other intergalactic material. 
C)  a radio-bright galaxy crossed by a dark, absorbing, edge-on disk, splitting the radio emissions into two as seen from Earth. 
D)  gravitational lensing of a distant radio source by a nearby galaxy or black hole.

Question 7

Galaxies in the universe are:

Accepted Answer

A)  distributed randomly, their density remaining approximately constant throughout space. 
B)  collected into superclusters that are concentrated along surfaces surrounding empty spaces that contain very few galaxies. 
C)  concentrated into a central supercluster with other clusters rotating about it in a huge, flat disk like a supergalaxy, with very few galaxies outside this disk. 
D)  all concentrated in spherical clusters, and these clusters are distributed uniformly throughout space. 
A)  distributed randomly, their density remaining approximately constant throughout space. 
B)  collected into superclusters that are concentrated along surfaces surrounding empty spaces that contain very few galaxies. 
C)  concentrated into a central supercluster with other clusters rotating about it in a huge, flat disk like a supergalaxy, with very few galaxies outside this disk. 
D)  all concentrated in spherical clusters, and these clusters are distributed uniformly throughout space.

Question 8

What is the relationship between the size of an object and the rate at which its radiant output can vary?

Accepted Answer

A)  Small objects can vary more rapidly. 
B)  Large objects can vary more rapidly. 
C)  The relationship depends on the wavelength of the radiant output. Large objects can vary more rapidly at long wavelengths and smaller objects can vary more rapidly at shorter wavelengths. 
D)  There is no relationship between size and variation rate. 
A)  Small objects can vary more rapidly. 
B)  Large objects can vary more rapidly. 
C)  The relationship depends on the wavelength of the radiant output. Large objects can vary more rapidly at long wavelengths and smaller objects can vary more rapidly at shorter wavelengths. 
D)  There is no relationship between size and variation rate.

Question 9

What is the Hubble classification of the Milky Way Galaxy?

Accepted Answer

A)  Sab 
B)  SBa 
C)  SBab 
D)  Because of the difficulty of examining the structure of the Milky Way from inside, the Galaxy has not been classified. 
A)  Sab 
B)  SBa 
C)  SBab 
D)  Because of the difficulty of examining the structure of the Milky Way from inside, the Galaxy has not been classified.

Question 10

Variations in the output of quasars within a few hours are an indication:

Accepted Answer

A)  of the rapid rotation of the sources. 
B)  that these objects are actually binary systems in which we see mutual eclipses. 
C)  of the relatively small size of the emitting regions. 
D)  of obscuring gas and dust clouds moving in front of them from our point of view. 
A)  of the rapid rotation of the sources. 
B)  that these objects are actually binary systems in which we see mutual eclipses. 
C)  of the relatively small size of the emitting regions. 
D)  of obscuring gas and dust clouds moving in front of them from our point of view.

Question 11

The Tully-Fisher relation provides a method of determining distances to galaxies by estimating the galaxy luminosity from a measurement of which parameter relating to the 21-cm atomic hydrogen radio emission line?

Accepted Answer

A)  width 
B)  position and hence Doppler shift from the rest wavelength 
C)  intensity 
D)  split between its two components 
A)  width 
B)  position and hence Doppler shift from the rest wavelength 
C)  intensity 
D)  split between its two components

Question 12

In 1917,Harlow Shapley plotted the positions of almost a hundred globular clusters.But the galactic plane is cloaked by gas and dust,and the best way to "see" through this is with long-wavelength radio waves.However,in 1917 radio astronomy did not exist.How did Shapley accomplish his task?

Accepted Answer

A)  He could only see globular clusters that were relatively close to the Sun. 
B)  He concentrated on using the long-wavelength end of the visible spectrum: red. This worked well because globular clusters are old and are dominated by red stars. 
C)  The globular clusters are mostly in a halo up off the galactic plane, so the dust was not a great problem. 
D)  In order to form a globular cluster, a great deal of interstellar dust is used up. Thus, globular clusters create holes in the dust and are relatively easy to see. 
A)  He could only see globular clusters that were relatively close to the Sun. 
B)  He concentrated on using the long-wavelength end of the visible spectrum: red. This worked well because globular clusters are old and are dominated by red stars. 
C)  The globular clusters are mostly in a halo up off the galactic plane, so the dust was not a great problem. 
D)  In order to form a globular cluster, a great deal of interstellar dust is used up. Thus, globular clusters create holes in the dust and are relatively easy to see.

Question 13

Who developed the "tuning fork" diagram connecting the different shapes of elliptical and spiral galaxies?

Accepted Answer

A)  Stephen Hawking 
B)  Ejnar Hertzsprung 
C)  Martin Schwarzschild 
D)  Edwin Hubble 
A)  Stephen Hawking 
B)  Ejnar Hertzsprung 
C)  Martin Schwarzschild 
D)  Edwin Hubble

Question 14

What name is given to a galaxy with a smooth distribution of brightness and a round shape?

Accepted Answer

A)  SBa 
B)  Sa 
C)  E7 
D)  E0 
A)  SBa 
B)  Sa 
C)  E7 
D)  E0

Question 15

Which types of clusters are NOT gravitationally bound?

Accepted Answer

A)  open star clusters and superclusters of galaxies 
B)  globular clusters and superclusters of galaxies 
C)  galaxy clusters and superclusters 
D)  globular clusters and galaxy clusters 
A)  open star clusters and superclusters of galaxies 
B)  globular clusters and superclusters of galaxies 
C)  galaxy clusters and superclusters 
D)  globular clusters and galaxy clusters

Question 16

How does the number of barred spiral galaxies in the universe compare with the number of ordinary spiral galaxies?

Accepted Answer

A)  Barred spirals outnumber ordinary spirals. 
B)  There are about equal numbers of barred spirals and ordinary spirals. 
C)  The question is meaningless-barred spirals are simply ordinary spirals seen edge-on. 
D)  Ordinary spirals outnumber barred spirals. 
A)  Barred spirals outnumber ordinary spirals. 
B)  There are about equal numbers of barred spirals and ordinary spirals. 
C)  The question is meaningless-barred spirals are simply ordinary spirals seen edge-on. 
D)  Ordinary spirals outnumber barred spirals.

Question 17

What is an SBc galaxy?

Accepted Answer

A)  a galaxy with a moderate nuclear bulge, moderately wound arms, and a bright core 
B)  a galaxy with a large nuclear bulge and tightly wound arms starting from the ends of a straight bar through the nuclear bulge 
C)  a galaxy with a small nuclear bulge and loosely wound arms coming from the center of the nuclear bulge 
D)  a galaxy with a small nuclear bulge and loosely wound arms starting from the ends of a straight bar through the nuclear bulge 
A)  a galaxy with a moderate nuclear bulge, moderately wound arms, and a bright core 
B)  a galaxy with a large nuclear bulge and tightly wound arms starting from the ends of a straight bar through the nuclear bulge 
C)  a galaxy with a small nuclear bulge and loosely wound arms coming from the center of the nuclear bulge 
D)  a galaxy with a small nuclear bulge and loosely wound arms starting from the ends of a straight bar through the nuclear bulge

Question 18

What do we expect to be the relationship between the number of active galaxies we detect and the number of active galaxies that actually exist?

Accepted Answer

A)  The energy output from active galaxies is so large that it is easy to detect them. Thus, we believe we have detected all that exist. 
B)  The nuclei of many active galaxies are hidden by dust in the accretion disk. Thus, we expect the actual number to be much greater than the observed number. 
C)  We cannot detect active galaxies unless the jets are pointed more or less toward Earth. The jets point toward Earth in only a few cases, so we expect the actual number to be greater than the observed number. 
D)  Active galaxies are created in galaxy collisions. But galaxy collisions occurred only in the early universe and are no longer occurring. The active galaxies all died off while their light was traveling to Earth. 
A)  The energy output from active galaxies is so large that it is easy to detect them. Thus, we believe we have detected all that exist. 
B)  The nuclei of many active galaxies are hidden by dust in the accretion disk. Thus, we expect the actual number to be much greater than the observed number. 
C)  We cannot detect active galaxies unless the jets are pointed more or less toward Earth. The jets point toward Earth in only a few cases, so we expect the actual number to be greater than the observed number. 
D)  Active galaxies are created in galaxy collisions. But galaxy collisions occurred only in the early universe and are no longer occurring. The active galaxies all died off while their light was traveling to Earth.

Question 19

The 21-cm line is one of the most important wavelengths in radio astronomy.It is produced mainly in:

Accepted Answer

A)  emission nebulae. 
B)  neutral hydrogen. 
C)  ionized hydrogen. 
D)  hot O and B stars. 
A)  emission nebulae. 
B)  neutral hydrogen. 
C)  ionized hydrogen. 
D)  hot O and B stars.

Question 20

What type of galaxy has a nuclear region of more or less uniform brightness from which long lanes of stars curve outward?

Accepted Answer

A)  spiral 
B)  quasar 
C)  irregular 
D)  elliptical 
A)  spiral 
B)  quasar 
C)  irregular 
D)  elliptical

Synchrotron radiation is produced whenever:

The observational fact about a Cepheid variable star that leads to a measurement of its distance from us is that its period of variation is directly related to its:

The first three strong radio sources,discovered by Reber in the 1930s and 1940s,did NOT include a:

Which characteristic does the Local Group of galaxies NOT have?

The mechanism that leads to the double-radio source phenomenon appears to be:

Galaxies in the universe are:

What is the relationship between the size of an object and the rate at which its radiant output can vary?

What is the Hubble classification of the Milky Way Galaxy?

Variations in the output of quasars within a few hours are an indication:

The Tully-Fisher relation provides a method of determining distances to galaxies by estimating the galaxy luminosity from a measurement of which parameter relating to the 21-cm atomic hydrogen radio emission line?

In 1917,Harlow Shapley plotted the positions of almost a hundred globular clusters.But the galactic plane is cloaked by gas and dust,and the best way to "see" through this is with long-wavelength radio waves.However,in 1917 radio astronomy did not exist.How did Shapley accomplish his task?

Who developed the "tuning fork" diagram connecting the different shapes of elliptical and spiral galaxies?

What name is given to a galaxy with a smooth distribution of brightness and a round shape?

Which types of clusters are NOT gravitationally bound?

How does the number of barred spiral galaxies in the universe compare with the number of ordinary spiral galaxies?

What is an SBc galaxy?

What do we expect to be the relationship between the number of active galaxies we detect and the number of active galaxies that actually exist?

The 21-cm line is one of the most important wavelengths in radio astronomy.It is produced mainly in:

What type of galaxy has a nuclear region of more or less uniform brightness from which long lanes of stars curve outward?

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

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Exam 13: The Galaxies

Synchrotron radiation is produced whenever:

The observational fact about a Cepheid variable star that leads to a measurement of its distance from us is that its period of variation is directly related to its:

The first three strong radio sources,discovered by Reber in the 1930s and 1940s,did NOT include a:

Which characteristic does the Local Group of galaxies NOT have?

The mechanism that leads to the double-radio source phenomenon appears to be:

Galaxies in the universe are:

What is the relationship between the size of an object and the rate at which its radiant output can vary?

What is the Hubble classification of the Milky Way Galaxy?

Variations in the output of quasars within a few hours are an indication:

The Tully-Fisher relation provides a method of determining distances to galaxies by estimating the galaxy luminosity from a measurement of which parameter relating to the 21-cm atomic hydrogen radio emission line?

In 1917,Harlow Shapley plotted the positions of almost a hundred globular clusters.But the galactic plane is cloaked by gas and dust,and the best way to "see" through this is with long-wavelength radio waves.However,in 1917 radio astronomy did not exist.How did Shapley accomplish his task?

Who developed the "tuning fork" diagram connecting the different shapes of elliptical and spiral galaxies?

What name is given to a galaxy with a smooth distribution of brightness and a round shape?

Which types of clusters are NOT gravitationally bound?

How does the number of barred spiral galaxies in the universe compare with the number of ordinary spiral galaxies?

What is an SBc galaxy?

What do we expect to be the relationship between the number of active galaxies we detect and the number of active galaxies that actually exist?

The 21-cm line is one of the most important wavelengths in radio astronomy.It is produced mainly in:

What type of galaxy has a nuclear region of more or less uniform brightness from which long lanes of stars curve outward?

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