Question 1

Where is the Sun located in the Milky Way Galaxy? (That is,what is the address of the Sun in the universe?)(See Figure 13-8 of Comins,Discovering the Essential Universe,6th ed.)

Accepted Answer

A)  in the Scutum-Centaurus arm 
B)  in the Sagittarius arm 
C)  in the Perseus arm 
D)  between the Sagittarius and Perseus arms. 
A)  in the Scutum-Centaurus arm 
B)  in the Sagittarius arm 
C)  in the Perseus arm 
D)  between the Sagittarius and Perseus arms.

Question 2

Consider a cluster of galaxies.What is increasing because of the Hubble flow?

Accepted Answer

A)  the average distance between galaxies 
B)  the sizes of the galaxies 
C)  spacetime 
D)  the average distance between the stars in each of the galaxies 
A)  the average distance between galaxies 
B)  the sizes of the galaxies 
C)  spacetime 
D)  the average distance between the stars in each of the galaxies

Question 3

The radio emission from the jets in a double-radio source is:

Accepted Answer

A)  recombination radiation from electrons combining with protons to form neutral hydrogen gas as the gas cools within the jets. 
B)  21-cm emission from neutral hydrogen atoms. 
C)  thermal emission from very hot matter ejected from the accretion disk around the central black hole. 
D)  synchrotron radiation from relativistic electrons spiraling in magnetic fields. 
A)  recombination radiation from electrons combining with protons to form neutral hydrogen gas as the gas cools within the jets. 
B)  21-cm emission from neutral hydrogen atoms. 
C)  thermal emission from very hot matter ejected from the accretion disk around the central black hole. 
D)  synchrotron radiation from relativistic electrons spiraling in magnetic fields.

Question 4

Cepheid variable stars are invaluable in astronomy because of the close relationship between:

Accepted Answer

A)  the peak wavelength of their spectra and their surface temperatures. 
B)  their luminosity, or absolute magnitude, and their pulsation period. 
C)  the redshift of their spectra and their distance from the Sun. 
D)  their apparent magnitude and their pulsation period. 
A)  the peak wavelength of their spectra and their surface temperatures. 
B)  their luminosity, or absolute magnitude, and their pulsation period. 
C)  the redshift of their spectra and their distance from the Sun. 
D)  their apparent magnitude and their pulsation period.

Question 5

A particular galaxy appears round,with a nuclear region of uniform brightness and an outer region that is broken up into long,curved,well-defined lanes of stars and light gas clouds.How would this galaxy be classified?

Accepted Answer

A)  elliptical 
B)  flocculent spiral 
C)  irregular 
D)  grand-design spiral 
A)  elliptical 
B)  flocculent spiral 
C)  irregular 
D)  grand-design spiral

Question 6

What observational evidence seems to indicate the presence of a supermassive black hole at the center of our neighboring galaxy,M31,in Andromeda?

Accepted Answer

A)  the slow but measurable motion of the Milky Way Galaxy toward M31 under the intense gravitational force of its black hole 
B)  very intense X-ray emission from a very small central core, indicating a very hot source 
C)  the spectroscopic measurements of extremely high and symmetric Doppler shifts from material orbiting rapidly around a massive object near the galactic center 
D)  a small but dark region on detailed photographs of M31, showing an area from which light cannot escape 
A)  the slow but measurable motion of the Milky Way Galaxy toward M31 under the intense gravitational force of its black hole 
B)  very intense X-ray emission from a very small central core, indicating a very hot source 
C)  the spectroscopic measurements of extremely high and symmetric Doppler shifts from material orbiting rapidly around a massive object near the galactic center 
D)  a small but dark region on detailed photographs of M31, showing an area from which light cannot escape

Question 7

What is a galactic halo?

Accepted Answer

A)  a system of arcs and other gas clouds surrounding a galactic nucleus 
B)  a system of satellite galaxies surrounding the Milky Way Galaxy 
C)  a spherical distribution of stars and globular clusters centered on a nuclear bulge 
D)  a large disk of stars and molecular clouds extending outward from a nuclear bulge 
A)  a system of arcs and other gas clouds surrounding a galactic nucleus 
B)  a system of satellite galaxies surrounding the Milky Way Galaxy 
C)  a spherical distribution of stars and globular clusters centered on a nuclear bulge 
D)  a large disk of stars and molecular clouds extending outward from a nuclear bulge

Question 8

One of the first three astronomical objects detected at radio wavelengths by Grote Reber in the late 1930s was:

Accepted Answer

A)  Jupiter. 
B)  the Sun. 
C)  the galactic center. 
D)  the Moon. 
A)  Jupiter. 
B)  the Sun. 
C)  the galactic center. 
D)  the Moon.

Question 9

How has the hot,X-ray-emitting intergalactic gas in galaxy clusters affected the dark matter problem for the clusters?

Accepted Answer

A)  The gas supplies the mass needed to solve the problem, which is now no longer a problem! 
B)  The gas supplies about 10 times too much mass-now the problem is how clusters so massive are not much more compact. 
C)  The gas supplies about 2/10 of the dark matter, so with the visible matter, about 7/10 of the mass required to stabilize the cluster is still missing. 
D)  The gas is very tenuous and supplies almost no mass at all; therefore, it has almost no effect on the dark matter problem. 
A)  The gas supplies the mass needed to solve the problem, which is now no longer a problem! 
B)  The gas supplies about 10 times too much mass-now the problem is how clusters so massive are not much more compact. 
C)  The gas supplies about 2/10 of the dark matter, so with the visible matter, about 7/10 of the mass required to stabilize the cluster is still missing. 
D)  The gas is very tenuous and supplies almost no mass at all; therefore, it has almost no effect on the dark matter problem.

Question 10

What is a peculiar galaxy?

Accepted Answer

A)  a galaxy with a supermassive black hole at the center 
B)  an older name for an active galaxy 
C)  a galaxy that looks like it is exploding 
D)  an active galaxy with large radiation output at many different wavelengths across the spectrum 
A)  a galaxy with a supermassive black hole at the center 
B)  an older name for an active galaxy 
C)  a galaxy that looks like it is exploding 
D)  an active galaxy with large radiation output at many different wavelengths across the spectrum

Question 11

Which statement is NOT a characteristic of elliptical galaxies?

Accepted Answer

A)  Elliptical galaxies are almost devoid of interstellar gas and dust. 
B)  Almost all star formation stopped in elliptical galaxies billions of years ago. 
C)  Different elliptical galaxies appear to be flattened by different amounts. 
D)  Elliptical galaxies have a disk and a central bulge but no spiral arms. 
A)  Elliptical galaxies are almost devoid of interstellar gas and dust. 
B)  Almost all star formation stopped in elliptical galaxies billions of years ago. 
C)  Different elliptical galaxies appear to be flattened by different amounts. 
D)  Elliptical galaxies have a disk and a central bulge but no spiral arms.

Question 12

What would happen if the Andromeda Galaxy (a spiral about the same size as the Milky Way Galaxy)collided with the Milky Way?

Accepted Answer

A)  The two galaxies would pass through each other, the stars sailing past one another unharmed, and the interstellar gas and dust clouds would collide to produce a burst of star formation. 
B)  The two galaxies would pass through each other almost unchanged with essentially no interactions at all. 
C)  The two galaxies would shatter or even explode, essentially destroying their stars and any life forms that there may have been (including us). 
D)  All the gas and dust clouds and a great many of the stars would collide with each other, stopping both galaxies and creating a galactic merger. 
A)  The two galaxies would pass through each other, the stars sailing past one another unharmed, and the interstellar gas and dust clouds would collide to produce a burst of star formation. 
B)  The two galaxies would pass through each other almost unchanged with essentially no interactions at all. 
C)  The two galaxies would shatter or even explode, essentially destroying their stars and any life forms that there may have been (including us). 
D)  All the gas and dust clouds and a great many of the stars would collide with each other, stopping both galaxies and creating a galactic merger.

Question 13

Compared with the total output of energy from the Milky Way Galaxy,what is the equivalent output of a typical quasar?

Accepted Answer

A)  only about 1/10 of the Galaxy's output but from a small volume of space 
B)  100 times brighter 
C)  about a million times brighter 
D)  about the same energy output 
A)  only about 1/10 of the Galaxy's output but from a small volume of space 
B)  100 times brighter 
C)  about a million times brighter 
D)  about the same energy output

Question 14

To what distance in parsecs can Cepheid variables now be seen with the Hubble Space Telescope?

Accepted Answer

A)  about 300 Mpc 
B)  about 30 Mpc 
C)  about 30 pc 
D)  about 200 Mpc 
A)  about 300 Mpc 
B)  about 30 Mpc 
C)  about 30 pc 
D)  about 200 Mpc

Question 15

If the Sun were traveling around the galactic center along with companion stars (all in circular orbits)as depicted in Figure 13-17 of Comins,Discovering the Essential Universe,6th ed.,from which star would you measure a Doppler shift of their light? (Hint: Think about relative velocities and orbital velocities at different orbital distances from the galactic center.)

Accepted Answer

A)  stars at the same orbital distance as the Sun 
B)  stars in directions 45° from the Sun's direction of motion 
C)  All the companion stars are moving along with the Sun and have no relative velocity with respect to it. 
D)  stars directly between the Sun and the galactic center 
A)  stars at the same orbital distance as the Sun 
B)  stars in directions 45° from the Sun's direction of motion 
C)  All the companion stars are moving along with the Sun and have no relative velocity with respect to it. 
D)  stars directly between the Sun and the galactic center

Question 16

The Hubble law indicates that:

Accepted Answer

A)  the Milky Way Galaxy appears to be at or near the center of the known universe. 
B)  all nearby superclusters of galaxies are moving toward us and all far-away superclusters are moving away from us. 
C)  the farther superclusters are receding faster than the nearby superclusters. 
D)  the universe will expand forever. 
A)  the Milky Way Galaxy appears to be at or near the center of the known universe. 
B)  all nearby superclusters of galaxies are moving toward us and all far-away superclusters are moving away from us. 
C)  the farther superclusters are receding faster than the nearby superclusters. 
D)  the universe will expand forever.

Question 17

A spiral galaxy has well-defined arms that are wound not-too-tightly around its intermediate-size bulge.This is MOST likely a:

Accepted Answer

A)  flocculent Sa. 
B)  grand-design Sb. 
C)  flocculent Sb. 
D)  grand-design Sc. 
A)  flocculent Sa. 
B)  grand-design Sb. 
C)  flocculent Sb. 
D)  grand-design Sc.

Question 18

What quantum transition occurs inside a hydrogen atom to produce a 21-cm radio photon?

Accepted Answer

A)  An electron falls from the n = 100 level to the n = 99 level in the atom. 
B)  An electron in the ground atomic state reverses its direction of spin with respect to that of the proton. 
C)  An electron reverses the direction of its motion in orbit around the proton. 
D)  The electron combines with the proton in the nucleus to become a neutron, producing energy. 
A)  An electron falls from the n = 100 level to the n = 99 level in the atom. 
B)  An electron in the ground atomic state reverses its direction of spin with respect to that of the proton. 
C)  An electron reverses the direction of its motion in orbit around the proton. 
D)  The electron combines with the proton in the nucleus to become a neutron, producing energy.

Question 19

Where do we find supermassive black holes?

Accepted Answer

A)  only in the centers of giant elliptical galaxies 
B)  only in the centers of active galaxies 
C)  in the centers of both active and normal galaxies, but only those at relatively high redshift values, indicating that they existed in the distant past 
D)  in the centers of both active and normal galaxies, both nearby and far away 
A)  only in the centers of giant elliptical galaxies 
B)  only in the centers of active galaxies 
C)  in the centers of both active and normal galaxies, but only those at relatively high redshift values, indicating that they existed in the distant past 
D)  in the centers of both active and normal galaxies, both nearby and far away

Question 20

The jets of material moving away from a supermassive black hole are generated by high pressures and temperatures at the base of the accretion disk.What causes these high pressures and temperatures?

Accepted Answer

A)  radioactivity 
B)  friction 
C)  hydrogen fusion 
D)  helium fusion 
A)  radioactivity 
B)  friction 
C)  hydrogen fusion 
D)  helium fusion

Where is the Sun located in the Milky Way Galaxy? (That is,what is the address of the Sun in the universe?)(See Figure 13-8 of Comins,Discovering the Essential Universe,6th ed.)

Consider a cluster of galaxies.What is increasing because of the Hubble flow?

The radio emission from the jets in a double-radio source is:

Cepheid variable stars are invaluable in astronomy because of the close relationship between:

A particular galaxy appears round,with a nuclear region of uniform brightness and an outer region that is broken up into long,curved,well-defined lanes of stars and light gas clouds.How would this galaxy be classified?

What observational evidence seems to indicate the presence of a supermassive black hole at the center of our neighboring galaxy,M31,in Andromeda?

What is a galactic halo?

One of the first three astronomical objects detected at radio wavelengths by Grote Reber in the late 1930s was:

How has the hot,X-ray-emitting intergalactic gas in galaxy clusters affected the dark matter problem for the clusters?

What is a peculiar galaxy?

Which statement is NOT a characteristic of elliptical galaxies?

What would happen if the Andromeda Galaxy (a spiral about the same size as the Milky Way Galaxy)collided with the Milky Way?

Compared with the total output of energy from the Milky Way Galaxy,what is the equivalent output of a typical quasar?

To what distance in parsecs can Cepheid variables now be seen with the Hubble Space Telescope?

The Hubble law indicates that:

A spiral galaxy has well-defined arms that are wound not-too-tightly around its intermediate-size bulge.This is MOST likely a:

What quantum transition occurs inside a hydrogen atom to produce a 21-cm radio photon?

Where do we find supermassive black holes?

The jets of material moving away from a supermassive black hole are generated by high pressures and temperatures at the base of the accretion disk.What causes these high pressures and temperatures?

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

Where is the Sun located in the Milky Way Galaxy? (That is,what is the address of the Sun in the universe?)(See Figure 13-8 of Comins,Discovering the Essential Universe,6th ed.)

Consider a cluster of galaxies.What is increasing because of the Hubble flow?

The radio emission from the jets in a double-radio source is:

Cepheid variable stars are invaluable in astronomy because of the close relationship between:

A particular galaxy appears round,with a nuclear region of uniform brightness and an outer region that is broken up into long,curved,well-defined lanes of stars and light gas clouds.How would this galaxy be classified?

What observational evidence seems to indicate the presence of a supermassive black hole at the center of our neighboring galaxy,M31,in Andromeda?

What is a galactic halo?

One of the first three astronomical objects detected at radio wavelengths by Grote Reber in the late 1930s was:

How has the hot,X-ray-emitting intergalactic gas in galaxy clusters affected the dark matter problem for the clusters?

What is a peculiar galaxy?

Which statement is NOT a characteristic of elliptical galaxies?

What would happen if the Andromeda Galaxy (a spiral about the same size as the Milky Way Galaxy)collided with the Milky Way?

Compared with the total output of energy from the Milky Way Galaxy,what is the equivalent output of a typical quasar?

To what distance in parsecs can Cepheid variables now be seen with the Hubble Space Telescope?

The Hubble law indicates that:

A spiral galaxy has well-defined arms that are wound not-too-tightly around its intermediate-size bulge.This is MOST likely a:

What quantum transition occurs inside a hydrogen atom to produce a 21-cm radio photon?

Where do we find supermassive black holes?

The jets of material moving away from a supermassive black hole are generated by high pressures and temperatures at the base of the accretion disk.What causes these high pressures and temperatures?

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