Question 1

Which one of these statements does NOT correctly describe typical elliptical galaxies?

Accepted Answer

A)  Typical elliptical galaxies have a central bulge and a disk but no spiral arms. 
B)  Typical elliptical galaxies have a smooth light distribution with various degrees of elongation from a circular shape. 
C)  Typical elliptical galaxies contain primarily low-mass stars. 
D)  Typical elliptical galaxies cover the entire range of masses from the smallest to the largest galaxies in the universe. 
A)  Typical elliptical galaxies have a central bulge and a disk but no spiral arms. 
B)  Typical elliptical galaxies have a smooth light distribution with various degrees of elongation from a circular shape. 
C)  Typical elliptical galaxies contain primarily low-mass stars. 
D)  Typical elliptical galaxies cover the entire range of masses from the smallest to the largest galaxies in the universe.

Question 2

Which of these expressions is the correct form of Hubble's law (H0 = Hubble's constant, r = distance, v = recessional velocity)?

Accepted Answer

A)  H0 * v = r 
B)  v = H0 * r 
C)  v = H0, which is constant 
D)  v * r = H0 
A)  H0 * v = r 
B)  v = H0 * r 
C)  v = H0, which is constant 
D)  v * r = H0

Question 3

Because of the expansion of space, astronomers see all distant galaxies moving away from Earth, with more distant galaxies moving faster. An observer in one of these distant galaxies would see all galaxies

Accepted Answer

A)  moving toward the observer, with more distant galaxies moving faster. 
B)  moving away from the observer, with closer galaxies moving faster. 
C)  moving away from the observer, with more distant galaxies moving faster. 
D)  on one side of the observer moving toward the observer and all galaxies on the other side moving away from the observer, with more distant galaxies moving faster. 
A)  moving toward the observer, with more distant galaxies moving faster. 
B)  moving away from the observer, with closer galaxies moving faster. 
C)  moving away from the observer, with more distant galaxies moving faster. 
D)  on one side of the observer moving toward the observer and all galaxies on the other side moving away from the observer, with more distant galaxies moving faster.

Question 4

Did the distribution of dark matter affect the initial formation of galaxies?

Accepted Answer

A)  No. The theory of the early formation of galaxies does not involve dark matter. 
B)  Yes. Spiral galaxies of all types appear to have formed only in the presence of supermassive black holes and abundant dark matter. 
C)  Yes. The greatest concentrations of dark matter appear to have led to the formation of the earliest giant ellipticals. 
D)  Yes. When the concentration of dark matter was not particularly large the formation of barred spirals resulted. 
A)  No. The theory of the early formation of galaxies does not involve dark matter. 
B)  Yes. Spiral galaxies of all types appear to have formed only in the presence of supermassive black holes and abundant dark matter. 
C)  Yes. The greatest concentrations of dark matter appear to have led to the formation of the earliest giant ellipticals. 
D)  Yes. When the concentration of dark matter was not particularly large the formation of barred spirals resulted.

Question 5

Which of these statements describes a way in which galaxies evolve on the Hubble tuning-fork diagram?

Accepted Answer

A)  Galaxies begin as type E0 and evolve to lenticular and then continue as either normal or barred spirals. 
B)  Galaxies are created as either normal or barred spirals, but either eventually evolves to lenticular. These then evolve through the various types of ellipticals. 
C)  Everything starts as a lenticular galaxy. Then, for reasons not well understood, the subsequent evolution is either as a spiral (normal or barred) or as an elliptical. 
D)  Spiral galaxies merge to form giant elliptical galaxies. 
A)  Galaxies begin as type E0 and evolve to lenticular and then continue as either normal or barred spirals. 
B)  Galaxies are created as either normal or barred spirals, but either eventually evolves to lenticular. These then evolve through the various types of ellipticals. 
C)  Everything starts as a lenticular galaxy. Then, for reasons not well understood, the subsequent evolution is either as a spiral (normal or barred) or as an elliptical. 
D)  Spiral galaxies merge to form giant elliptical galaxies.

Question 6

What is the dominant radiation from the intergalactic matter in rich clusters of galaxies?

Accepted Answer

A)  ultraviolet light from electrons spiraling in magnetic fields 
B)  infrared radiation from dust 
C)  X-rays from very hot gas 
D)  21-cm radio radiation from cool, neutral hydrogen gas 
A)  ultraviolet light from electrons spiraling in magnetic fields 
B)  infrared radiation from dust 
C)  X-rays from very hot gas 
D)  21-cm radio radiation from cool, neutral hydrogen gas

Question 7

Dark, unknown forms of matter appear to make up about what fraction of the mass of a typical rich cluster of galaxies?

Accepted Answer

A)  one-half 
B)  90% 
C)  much less than 1% 
D)  10% 
A)  one-half 
B)  90% 
C)  much less than 1% 
D)  10%

Question 8

Which of these accurately characterizes an apparent dilemma in understanding the spiral arm structure of a typical spiral galaxy?

Accepted Answer

A)  The measured speeds of stars in the galaxy are exactly correct for the present spiral structure, having spun the observed tightness of the spiral in the typical lifetime of a galaxy. 
B)  If the measured speeds of stars in the galaxy had spun the arms into shape, these arms would be far less tightly wound than the observed arms. 
C)  If the measured speeds of stars in the galaxy had spun the arms into shape, these arms would be far more tightly wound than the observed arms. 
D)  The measured speeds of material in the spiral arms should not have led to any spiral but should have generated a straight bar rotating like a solid object. 
A)  The measured speeds of stars in the galaxy are exactly correct for the present spiral structure, having spun the observed tightness of the spiral in the typical lifetime of a galaxy. 
B)  If the measured speeds of stars in the galaxy had spun the arms into shape, these arms would be far less tightly wound than the observed arms. 
C)  If the measured speeds of stars in the galaxy had spun the arms into shape, these arms would be far more tightly wound than the observed arms. 
D)  The measured speeds of material in the spiral arms should not have led to any spiral but should have generated a straight bar rotating like a solid object.

Question 9

Which one of these statements about the spiral arms of grand-design spirals is true?

Accepted Answer

A)  The density of matter in the spiral arms is many times the density of the regions in between. 
B)  The regions between the spiral arms are cloaked in dust, which makes them look dimmer than the spiral arms. 
C)  The spiral density waves, which move around the galaxy, are transverse waves, moving up and down across the direction of the waves motion like light waves. 
D)  The spiral arms have almost the same density as the rest of the disk. They are more visible because they contain bright, newly formed stars. 
A)  The density of matter in the spiral arms is many times the density of the regions in between. 
B)  The regions between the spiral arms are cloaked in dust, which makes them look dimmer than the spiral arms. 
C)  The spiral density waves, which move around the galaxy, are transverse waves, moving up and down across the direction of the waves motion like light waves. 
D)  The spiral arms have almost the same density as the rest of the disk. They are more visible because they contain bright, newly formed stars.

Question 10

Why do the spiral arms show up so clearly in spiral galaxies?

Accepted Answer

A)  Stars are spread almost uniformly over the galaxy (outside the nuclear bulge), but the brightest stars occur only in the spiral arms, where their brightness and the fact that they illuminate gas clouds make the arms stand out. 
B)  Stars are spread uniformly over the galaxy, but the dust forms a spiral pattern, absorbing starlight; the spiral arms are the dust-free regions between the dust lanes. 
C)  The number of stars in the arms is several times larger than in the regions between, so these arms are reasonably distinct. 
D)  Stars occur only in the spiral arms (and the nuclear bulge), with essentially none between the arms, so the arms show up very distinctly. 
A)  Stars are spread almost uniformly over the galaxy (outside the nuclear bulge), but the brightest stars occur only in the spiral arms, where their brightness and the fact that they illuminate gas clouds make the arms stand out. 
B)  Stars are spread uniformly over the galaxy, but the dust forms a spiral pattern, absorbing starlight; the spiral arms are the dust-free regions between the dust lanes. 
C)  The number of stars in the arms is several times larger than in the regions between, so these arms are reasonably distinct. 
D)  Stars occur only in the spiral arms (and the nuclear bulge), with essentially none between the arms, so the arms show up very distinctly.

Question 11

Globular clusters

Accepted Answer

A)  are young formations and always contain many hot O- and B-type stars. 
B)  are old formations and always contain only old, red stars. 
C)  can be formed in collisions of galaxies and thus can be young if the collision occurred recently. 
D)  are continually forming in spiral galaxies, like the Milky Way, and thus they show a great range of ages in any one galaxy. 
A)  are young formations and always contain many hot O- and B-type stars. 
B)  are old formations and always contain only old, red stars. 
C)  can be formed in collisions of galaxies and thus can be young if the collision occurred recently. 
D)  are continually forming in spiral galaxies, like the Milky Way, and thus they show a great range of ages in any one galaxy.

Question 12

What is a rich cluster of galaxies?

Accepted Answer

A)  cluster with more spiral galaxies than ellipticals 
B)  cluster (like the Local Group) that contains at least two large galaxies 
C)  cluster with a high metal content 
D)  cluster containing thousands of galaxies 
A)  cluster with more spiral galaxies than ellipticals 
B)  cluster (like the Local Group) that contains at least two large galaxies 
C)  cluster with a high metal content 
D)  cluster containing thousands of galaxies

Question 13

For which objects in the universe has the Hubble relation been shown to hold experimentally?

Accepted Answer

A)  galaxies in the Local Group, in the near vicinity of the Milky Way 
B)  stars in the Milky Way in the near neighborhood of the Sun 
C)  distant galaxies 
D)  stars in the distant spiral arms of the Milky Way Galaxy 
A)  galaxies in the Local Group, in the near vicinity of the Milky Way 
B)  stars in the Milky Way in the near neighborhood of the Sun 
C)  distant galaxies 
D)  stars in the distant spiral arms of the Milky Way Galaxy

Question 14

What is a starburst galaxy?

Accepted Answer

A)  galaxy with streams of stars arching out from one place as if from an explosion 
B)  galaxy with an unusually large number of red giant stars 
C)  galaxy that is still in the process of formation from the intergalactic medium and undergoing its first star formation 
D)  galaxy with an unusually large number of newborn stars 
A)  galaxy with streams of stars arching out from one place as if from an explosion 
B)  galaxy with an unusually large number of red giant stars 
C)  galaxy that is still in the process of formation from the intergalactic medium and undergoing its first star formation 
D)  galaxy with an unusually large number of newborn stars

Question 15

How many barred spiral galaxies are there compared with ordinary spiral galaxies?

Accepted Answer

A)  There are about half as many barred spirals as there are ordinary spirals. 
B)  There are about twice as many barred spirals as there are ordinary spirals. 
C)  About 1 in 10 spiral galaxies contains a bar. 
D)  The numbers are essentially equal. 
A)  There are about half as many barred spirals as there are ordinary spirals. 
B)  There are about twice as many barred spirals as there are ordinary spirals. 
C)  About 1 in 10 spiral galaxies contains a bar. 
D)  The numbers are essentially equal.

Question 16

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 17

Many rich, regular clusters of galaxies contain substantial amounts of very hot, intergalactic gas. What is believed to have produced this hot gas?

Accepted Answer

A)  collisions between galaxies in the cluster 
B)  bursts of star formation in merging galaxies 
C)  supernovae (exploding stars) 
D)  jets of gas ejected by supermassive black holes at the centers of the galaxies 
A)  collisions between galaxies in the cluster 
B)  bursts of star formation in merging galaxies 
C)  supernovae (exploding stars) 
D)  jets of gas ejected by supermassive black holes at the centers of the galaxies

Question 18

At visible wavelengths, which galaxies are the brightest in the universe?

Accepted Answer

A)  giant elliptical galaxies 
B)  lenticular galaxies 
C)  large spiral galaxies like the Milky Way 
D)  starburst galaxies 
A)  giant elliptical galaxies 
B)  lenticular galaxies 
C)  large spiral galaxies like the Milky Way 
D)  starburst galaxies

Question 19

In the 1970s it was discovered that, among spiral galaxies, the wider the 21-cm radio emission line, the brighter is the galaxy. What is the name of this relation?

Accepted Answer

A)  mass-luminosity law 
B)  Hawking effect 
C)  Hubble law 
D)  Tully-Fisher relation 
A)  mass-luminosity law 
B)  Hawking effect 
C)  Hubble law 
D)  Tully-Fisher relation

Question 20

Which of these characteristics 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

Which one of these statements does NOT correctly describe typical elliptical galaxies?

Which of these expressions is the correct form of Hubble's law (H₀ = Hubble's constant, r = distance, v = recessional velocity)?

Because of the expansion of space, astronomers see all distant galaxies moving away from Earth, with more distant galaxies moving faster. An observer in one of these distant galaxies would see all galaxies

Did the distribution of dark matter affect the initial formation of galaxies?

Which of these statements describes a way in which galaxies evolve on the Hubble tuning-fork diagram?

What is the dominant radiation from the intergalactic matter in rich clusters of galaxies?

Dark, unknown forms of matter appear to make up about what fraction of the mass of a typical rich cluster of galaxies?

Which of these accurately characterizes an apparent dilemma in understanding the spiral arm structure of a typical spiral galaxy?

Which one of these statements about the spiral arms of grand-design spirals is true?

Why do the spiral arms show up so clearly in spiral galaxies?

Globular clusters

What is a rich cluster of galaxies?

For which objects in the universe has the Hubble relation been shown to hold experimentally?

What is a starburst galaxy?

How many barred spiral galaxies are there compared with ordinary spiral galaxies?

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?

Many rich, regular clusters of galaxies contain substantial amounts of very hot, intergalactic gas. What is believed to have produced this hot gas?

At visible wavelengths, which galaxies are the brightest in the universe?

In the 1970s it was discovered that, among spiral galaxies, the wider the 21-cm radio emission line, the brighter is the galaxy. What is the name of this relation?

Which of these characteristics does the Local Group of galaxies NOT have?

Discovering the Night Sky

Gravitation and the Motion of the Planets

Light and Telescopes

Atomic Physics and Spectra

Exoplanets and the Formation of Planetary Systems

Formation of the Solar System

Earth and the Moon

The Other Terrestrial Planets

The Outer Planets

Vagabonds of the Solar System

The Sun: Our Extraordinary Star

Characterizing Stars

The Lives of Stars From Birth Through Middle Age

The Death of Stars

Black Holes: Matters of Gravity

The Milky Way Galaxy

Quasars and Other Active Galaxies

Cosmology

Astrobiology

Filters

Exam 17: Galaxies

Which one of these statements does NOT correctly describe typical elliptical galaxies?

Which of these expressions is the correct form of Hubble's law (H0 = Hubble's constant, r = distance, v = recessional velocity)?

Because of the expansion of space, astronomers see all distant galaxies moving away from Earth, with more distant galaxies moving faster. An observer in one of these distant galaxies would see all galaxies

Did the distribution of dark matter affect the initial formation of galaxies?

Which of these statements describes a way in which galaxies evolve on the Hubble tuning-fork diagram?

What is the dominant radiation from the intergalactic matter in rich clusters of galaxies?

Dark, unknown forms of matter appear to make up about what fraction of the mass of a typical rich cluster of galaxies?

Which of these accurately characterizes an apparent dilemma in understanding the spiral arm structure of a typical spiral galaxy?

Which one of these statements about the spiral arms of grand-design spirals is true?

Why do the spiral arms show up so clearly in spiral galaxies?

Globular clusters

What is a rich cluster of galaxies?

For which objects in the universe has the Hubble relation been shown to hold experimentally?

What is a starburst galaxy?

How many barred spiral galaxies are there compared with ordinary spiral galaxies?

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?

Many rich, regular clusters of galaxies contain substantial amounts of very hot, intergalactic gas. What is believed to have produced this hot gas?

At visible wavelengths, which galaxies are the brightest in the universe?

In the 1970s it was discovered that, among spiral galaxies, the wider the 21-cm radio emission line, the brighter is the galaxy. What is the name of this relation?

Which of these characteristics does the Local Group of galaxies NOT have?

Discovering the Night Sky

Gravitation and the Motion of the Planets

Light and Telescopes

Atomic Physics and Spectra

Exoplanets and the Formation of Planetary Systems

Formation of the Solar System

Earth and the Moon

The Other Terrestrial Planets

The Outer Planets

Vagabonds of the Solar System

The Sun: Our Extraordinary Star

Characterizing Stars

The Lives of Stars From Birth Through Middle Age

The Death of Stars

Black Holes: Matters of Gravity

The Milky Way Galaxy

Quasars and Other Active Galaxies

Cosmology

Astrobiology

Filters

Which of these expressions is the correct form of Hubble's law (H₀ = Hubble's constant, r = distance, v = recessional velocity)?