Question 1

An elliptical galaxy typically contains which of these kinds of stars?

Accepted Answer

A)   primarily young, metal-rich stars
B)   stars of all ages, but all metal-poor
C)   primarily old, metal-poor stars
D)   stars of all ages from young, metal-rich stars to old, metal-poor starsE) B) and D)
F) B) and C)

Question 2

At present, how far away are the MOST distant galaxies astronomers have observed?

Accepted Answer

A)   970 million ly
B)   6.7 billion ly
C)   13.4 billion ly
D)   56 billion lyE) B) and D)
F) None of the above

Question 3

The biggest and intrinsically brightest galaxies in the universe are members of which group?

Accepted Answer

A)   irregular galaxies
B)   barred spirals
C)   large spirals
D)   ellipticalsE) None of the above
F) B) and C)

Question 4

Starburst galaxies are characterized by an abundance of stars in the process of formation. As a result, these galaxies send out an unusually large amount of electromagnetic radiation in which of these ranges?

Accepted Answer

A)   X-ray
B)   visible
C)   infrared
D)   radioE) A) and B)
F) A) and C)

Question 5

The expansion of the universe takes place

Accepted Answer

A)   only over distances about the size of a galaxy or larger; consequently, the Milky Way Galaxy expands, but the solar system does not.
B)   only between objects separated by a vacuum; as a result, the bodies do not expand, but the Earth-Moon system does.
C)   between all objects, even between the atoms in the bodies, although the expansion of a person is too small to be measured reliably.
D)   primarily in the huge voids between clusters of galaxies. "Small" objects like galaxies or Earth do not expand.E) A) and B)
F) None of the above

Question 6

Which of these phenomena is NOT produced by collisions between galaxies?

Accepted Answer

A)   hot interstellar gas, detected by recent space-borne X-ray telescopes
B)   concentration of galaxies into clusters and superclusters
C)   distorted spiral arms in many galaxies
D)   initiation of significant new star formation in so-called starburst galaxiesE) A) and B)
F) A) and C)

Question 7

How does the winding dilemma affect flocculent spirals?

Accepted Answer

A)   The winding dilemma is the basic cause of the chaotic structure in flocculent spirals.
B)   The winding dilemma affects only galaxies with flat rotation curves and constant stellar speeds, and this does not include flocculent spirals.
C)   Flocculent spirals are dominated by self-propagating star formation in which groups of stars are formed and then fade as the massive luminous stars complete their life cycles. This transient, spotty star-formation pattern is unaffected by the winding dilemma.
D)   Flocculent spirals have a whirlpool structure with several centers of rotation, each affected by the winding dilemma. This results in the overall flocculent pattern.E) All of the above
F) B) and D)

Question 8

According to the theory of self-propagating star formation, the spiral arms of flocculent spiral galaxies are broad and poorly designed because

Accepted Answer

A)   the spiral arms in these galaxies are strongly influenced by the black hole at the center of the galaxy.
B)   the density wave has been disrupted by the bar across the center of the galaxy.
C)   dust lanes occur in broad bands rather than in the narrow bands found in grand-design spirals.
D)   the spiral arm segments are defined only by the relatively short-lived O- and B-type stars.E) C) and D)
F) A) and B)

Question 9

An astronomer studying a distant cluster of galaxies finds that several of the galaxies are spiral-shaped, with a small nuclear region and loosely wound arms. How should the astronomer classify these galaxies?

Accepted Answer

A)   Sa
B)   SBb
C)   Sc
D)   SbE) A) and C)
F) A) and B)

Question 10

A spherical cluster of several hundred galaxies is found to contain far more ellipticals than spirals and irregulars. How would one classify this cluster?

Accepted Answer

A)   poor regular
B)   poor irregular
C)   rich regular
D)   rich irregularE) A) and D)
F) B) and C)

Question 11

The Hubble law implies that distances are increasing between

Accepted Answer

A)   the proton and electron in hydrogen.
B)   the planets and the Sun.
C)   galaxies in the Local Group.
D)   superclusters of galaxies.E) A) and B)
F) B) and D)

Question 12

A spiral galaxy is observed edge-on so that its spiral arms are barely visible. The galaxy, however, is observed to have a very large nuclear bulge. Thus, this galaxy

Accepted Answer

A)   is probably type Sa.
B)   is probably type Sb.
C)   is probably type Sc.
D)   cannot be classified if its spiral arms cannot be studied.E) B) and D)
F) None of the above

Question 13

Inside of galaxy clusters, which of these components contains about twice as much mass as the stars inside the cluster's galaxies?

Accepted Answer

A)   large numbers of cool, dark, brown dwarf stars floating in the galaxy cluster
B)   very hot intergalactic gas emitting X-rays in clusters.
C)   a tremendous flux of neutrinos, which have recently been shown to have mass, coming from these clusters.
D)   large numbers of small but massive black holes within every galaxy.E) A) and C)
F) A) and B)

Question 14

An astronomer studying a distant cluster of galaxies finds that several of the galaxies are spiral-shaped, with a nuclear region of moderate size and moderately wound arms. How should the astronomer classify these galaxies?

Accepted Answer

A)   SBa
B)   Sc
C)   Sb
D)   SaE) A) and D)
F) B) and D)

Question 15

Which one of these statements about clusters of galaxies is true?

Accepted Answer

A)   The observed mass of the galaxies of the cluster is many thousands of times too small to hold the cluster together.
B)   The observed mass of the galaxies of the cluster is about 10 times larger than the amount needed to hold the cluster together.
C)   The observed mass of the galaxies in the cluster is about 10 times too small to hold the cluster together.
D)   The observed mass of the galaxies of the cluster is almost exactly equal to the mass needed to hold the cluster together.E) C) and D)
F) B) and D)

Question 16

What is a probable mechanism for the initial triggering, and the subsequent maintenance, of the density wave that forms the visible arms in spiral galaxies?

Accepted Answer

A)   equivalent of a massive "sound" wave generated at the center of the galaxy by the gravitational energy release at the initial formation of the galaxy, producing progressive compression of material that is shaped by galaxy rotation
B)   gravitational influence from the rotating central supermassive black hole at the galactic center of the arm material
C)   gravitational interaction from the close passage of another galaxy
D)   shock waves from supernova explosions of massive stars within the spiral armsE) A) and C)
F) All of the above

Question 17

An astronomer studying a distant cluster of galaxies finds that several of the galaxies are spiral-shaped, with a large nuclear region and tightly wound arms. How should the astronomer classify these galaxies?

Accepted Answer

A)   Sb
B)   SBb
C)   Sa
D)   ScE) None of the above
F) B) and D)

Question 18

How are superclusters spread throughout the universe?

Accepted Answer

A)   Superclusters are distributed more or less evenly (i.e., at random)  throughout the universe.
B)   Superclusters are distributed in long lines that cover the universe like a gigantic fishing net.
C)   Superclusters are separated by large voids, appearing at the intersection of filaments.
D)   Superclusters are grouped into clusters of superclusters that in turn are grouped into clusters of clusters, and so on.E) A) and B)
F) B) and C)

Question 19

What mechanism is believed to produce grand-design spiral galaxies?

Accepted Answer

A)   shock waves from explosive star formation in the nuclear bulge
B)   density waves in the interstellar medium
C)   satellite galaxies plunging through the disk of the nuclear spiral galaxy
D)   self-propagating star formation, where star formation occurs in burstsE) C) and D)
F) A) and C)

Question 20

Hubble's law for distant galaxies, with H0 being Hubble's constant, states that

Accepted Answer

A)   H0 * recessional speed = distance.
B)   recessional speed = H0 *distance.
C)   recessional speed = H0, which is constant.
D)   recessional speed * distance = H0.E) B) and C)
F) C) and D)

Exam 17: Galaxies

What mechanism is believed to produce grand-design spiral galaxies?

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Hubble's law for distant galaxies, with H0 being Hubble's constant, states that

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The Hubble law implies that distances are increasing between

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A spherical cluster of several hundred galaxies is found to contain far more ellipticals than spirals and irregulars. How would one classify this cluster?

Correct AnswerverifiedShow Answer

According to the theory of self-propagating star formation, the spiral arms of flocculent spiral galaxies are broad and poorly designed because

Correct AnswerverifiedShow Answer

An astronomer studying a distant cluster of galaxies finds that several of the galaxies are spiral-shaped, with a nuclear region of moderate size and moderately wound arms. How should the astronomer classify these galaxies?

Correct AnswerverifiedShow Answer

What is a probable mechanism for the initial triggering, and the subsequent maintenance, of the density wave that forms the visible arms in spiral galaxies?

Correct AnswerverifiedShow Answer

An elliptical galaxy typically contains which of these kinds of stars?

Correct AnswerverifiedShow Answer

Inside of galaxy clusters, which of these components contains about twice as much mass as the stars inside the cluster's galaxies?

Correct AnswerverifiedShow Answer

A spiral galaxy is observed edge-on so that its spiral arms are barely visible. The galaxy, however, is observed to have a very large nuclear bulge. Thus, this galaxy

Correct AnswerverifiedShow Answer

An astronomer studying a distant cluster of galaxies finds that several of the galaxies are spiral-shaped, with a large nuclear region and tightly wound arms. How should the astronomer classify these galaxies?

Correct AnswerverifiedShow Answer

The expansion of the universe takes place

Correct AnswerverifiedShow Answer

An astronomer studying a distant cluster of galaxies finds that several of the galaxies are spiral-shaped, with a small nuclear region and loosely wound arms. How should the astronomer classify these galaxies?

Correct AnswerverifiedShow Answer

Which one of these statements about clusters of galaxies is true?

Correct AnswerverifiedShow Answer

Which of these phenomena is NOT produced by collisions between galaxies?

Correct AnswerverifiedShow Answer

At present, how far away are the MOST distant galaxies astronomers have observed?

Correct AnswerverifiedShow Answer

The biggest and intrinsically brightest galaxies in the universe are members of which group?

Correct AnswerverifiedShow Answer

How does the winding dilemma affect flocculent spirals?

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How are superclusters spread throughout the universe?

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Starburst galaxies are characterized by an abundance of stars in the process of formation. As a result, these galaxies send out an unusually large amount of electromagnetic radiation in which of these ranges?

Correct AnswerverifiedShow Answer

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Hubble's law for distant galaxies, with H₀ being Hubble's constant, states that

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