Question 1

Variable stars,such as Cepheid variables and RR Lyrae stars,are used in what important measurement in astronomy?

Accepted Answer

A)  Keeping of accurate time 
B)  Measurement of the gravitational fields of supermassive black holes by their effect upon the star's pulsation rate 
C)  Measurement of the surface temperatures of stars 
D)  Measurement of distances to galaxies 
A)  Keeping of accurate time 
B)  Measurement of the gravitational fields of supermassive black holes by their effect upon the star's pulsation rate 
C)  Measurement of the surface temperatures of stars 
D)  Measurement of distances to galaxies

Question 2

How is the mass of the Galaxy estimated?

Accepted Answer

A)  By observing the bending of light from distant galaxies as it passes near the Milky Way center 
B)  By observing its movement toward neighboring galaxies due to gravitational attraction 
C)  By counting stars and assuming an average stellar mass 
D)  By applying Newton's extension of Kepler's laws to the motion of the Sun and other stars 
A)  By observing the bending of light from distant galaxies as it passes near the Milky Way center 
B)  By observing its movement toward neighboring galaxies due to gravitational attraction 
C)  By counting stars and assuming an average stellar mass 
D)  By applying Newton's extension of Kepler's laws to the motion of the Sun and other stars

Question 3

When distances were carefully measured from Earth to globular clusters above and below the Milky Way plane (where our view of them is not obscured by interstellar dust and gas),their distribution was found to be

Accepted Answer

A)  in a relatively flat disk almost perpendicular to the plane of the Galaxy,with relatively higher density of clusters toward its center. 
B)  spherically symmetric about a point in the constellation Sagittarius and concentrated in that direction. 
C)  concentrated in the plane of the Milky Way and clustered around the Sun's position,indicating that the Sun is close to the Galaxy's center. 
D)  uniformly distributed throughout space,with no concentration in any area of the Milky Way Galaxy. 
A)  in a relatively flat disk almost perpendicular to the plane of the Galaxy,with relatively higher density of clusters toward its center. 
B)  spherically symmetric about a point in the constellation Sagittarius and concentrated in that direction. 
C)  concentrated in the plane of the Milky Way and clustered around the Sun's position,indicating that the Sun is close to the Galaxy's center. 
D)  uniformly distributed throughout space,with no concentration in any area of the Milky Way Galaxy.

Question 4

Cepheid stars are useful to astronomers as indicators of

Accepted Answer

A)  white dwarf star behavior. 
B)  distance,particularly to stars in our Galaxy and to nearby galaxies. 
C)  stars with very high-speed motion. 
D)  the mechanics of eclipsing variable stars. 
A)  white dwarf star behavior. 
B)  distance,particularly to stars in our Galaxy and to nearby galaxies. 
C)  stars with very high-speed motion. 
D)  the mechanics of eclipsing variable stars.

Question 5

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

Accepted Answer

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

Question 6

If the Galaxy were spinning like our solar system,stars farther out from the center would

Accepted Answer

A)  have higher speeds than those near the center. 
B)  have lower speeds than those near the center. 
C)  have the same speeds as those near the center. 
D)  eventually fly apart from the immense speed. 
A)  have higher speeds than those near the center. 
B)  have lower speeds than those near the center. 
C)  have the same speeds as those near the center. 
D)  eventually fly apart from the immense speed.

Question 7

The 21-cm emission is used mainly to map out globular clusters around the Galaxy.

Accepted Answer

A) True 
 B)False

Question 8

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

Accepted Answer

A)  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. 
B)  Stars are spread almost uniformly throughout the disk of the galaxy outside the nuclear bulge,but the brightest stars occur only in the spiral arms,making the arms stand out. 
C)  There are many more stars in the arms than in the regions between the arms,so the arms stand out distinctly. 
D)  Stars occur only in the spiral arms (and the nuclear bulge),with essentially none between the arms,making the arms stand out brightly. 
A)  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. 
B)  Stars are spread almost uniformly throughout the disk of the galaxy outside the nuclear bulge,but the brightest stars occur only in the spiral arms,making the arms stand out. 
C)  There are many more stars in the arms than in the regions between the arms,so the arms stand out distinctly. 
D)  Stars occur only in the spiral arms (and the nuclear bulge),with essentially none between the arms,making the arms stand out brightly.

Question 9

If the Galaxy were spinning like a solid disk,stars farther out from the center would

Accepted Answer

A)  have higher speeds than those near the center. 
B)  have lower speeds than those near the center. 
C)  have the same speeds as those near the center. 
D)  eventually fly apart from the immense speed. 
A)  have higher speeds than those near the center. 
B)  have lower speeds than those near the center. 
C)  have the same speeds as those near the center. 
D)  eventually fly apart from the immense speed.

Question 10

Where in the Milky Way would you expect most star formation to be taking place?

Accepted Answer

A)  Globular clusters 
B)  The halo 
C)  The disk and spiral arms 
D)  The bulge 
A)  Globular clusters 
B)  The halo 
C)  The disk and spiral arms 
D)  The bulge

Question 11

In determining the distance to a galaxy by using observations of a Cepheid variable star,which of the following is NOT needed?

Accepted Answer

A)  The star's velocity via the Doppler effect 
B)  The Cepheid's period of variability 
C)  The type of spectrum of the Cepheid: metal-rich or metal-poor 
D)  The star's average brightness or apparent magnitude 
A)  The star's velocity via the Doppler effect 
B)  The Cepheid's period of variability 
C)  The type of spectrum of the Cepheid: metal-rich or metal-poor 
D)  The star's average brightness or apparent magnitude

Question 12

What evidence now exists for a supermassive black hole at the center of our Galaxy?

Accepted Answer

A)  A very dark void in an otherwise bright region of space near the galactic center,indicating the presence of a black hole 
B)  Observations of intense inflow of matter toward the center of the Galaxy,as seen by light-Doppler-shifted toward the red-emitted by this matter 
C)  An absence of gas clouds surrounding the region of space near the galactic center 
D)  Very rapid motion of matter close to the nucleus of the Galaxy,requiring a very massive body to hold it in orbit 
A)  A very dark void in an otherwise bright region of space near the galactic center,indicating the presence of a black hole 
B)  Observations of intense inflow of matter toward the center of the Galaxy,as seen by light-Doppler-shifted toward the red-emitted by this matter 
C)  An absence of gas clouds surrounding the region of space near the galactic center 
D)  Very rapid motion of matter close to the nucleus of the Galaxy,requiring a very massive body to hold it in orbit

Question 13

What is the evidence that indicates to some astronomers that a supermassive black hole exists at the center of our Galaxy?

Accepted Answer

A)  No electromagnetic radiation at all comes from the precise position of the galactic center and it just looks like a dark void in space. 
B)  Measurement of stars orbiting the galactic center at very high speeds,which would rapidly move out of the Galaxy unless some very massive object holds them in orbit 
C)  Doppler shift of light from stars in the near neighborhood of the galactic center,which indicates that the stars are falling inward at very high speeds 
D)  The Sun's motion in space shows that,if Kepler's law holds for its orbit around the galactic center,there must be a very massive object at this center. 
A)  No electromagnetic radiation at all comes from the precise position of the galactic center and it just looks like a dark void in space. 
B)  Measurement of stars orbiting the galactic center at very high speeds,which would rapidly move out of the Galaxy unless some very massive object holds them in orbit 
C)  Doppler shift of light from stars in the near neighborhood of the galactic center,which indicates that the stars are falling inward at very high speeds 
D)  The Sun's motion in space shows that,if Kepler's law holds for its orbit around the galactic center,there must be a very massive object at this center.

Question 14

In the self-propagating star formation theory,

Accepted Answer

A)  spiral arms are formed and sustained primarily by the actions of solar mass stars because there are so many more solar mass stars than high-mass stars. 
B)  spiral arms are poorly defined because they are formed and sustained primarily by the actions of short-lived massive stars. 
C)  the passage of dust clouds through the spiral arms triggers star formation. 
D)  spiral structure results with thin,well-defined arms. 
A)  spiral arms are formed and sustained primarily by the actions of solar mass stars because there are so many more solar mass stars than high-mass stars. 
B)  spiral arms are poorly defined because they are formed and sustained primarily by the actions of short-lived massive stars. 
C)  the passage of dust clouds through the spiral arms triggers star formation. 
D)  spiral structure results with thin,well-defined arms.

Question 15

Halo stars and globular clusters move in orbits that are oriented at random angles to the plane of the disk of a galaxy.

Accepted Answer

A) True 
 B)False

Question 16

Stars in the disk of the Galaxy are mostly old,metal-poor,Population II stars.

Accepted Answer

A) True 
 B)False

Question 17

Which of the following components of the Galaxy best outline the spiral arms of the Galaxy?

Accepted Answer

A)  Young O and B stars,dust,and gas 
B)  Globular clusters 
C)  Predominantly solar-type stars 
D)  White dwarf stars 
A)  Young O and B stars,dust,and gas 
B)  Globular clusters 
C)  Predominantly solar-type stars 
D)  White dwarf stars

Question 18

The Milky Way is an irregular galaxy.

Accepted Answer

A) True 
 B)False

Question 19

The halo of the Galaxy is a spherical distribution that is traced by globular clusters.

Accepted Answer

A) True 
 B)False

Question 20

Why are we able to see only a small part of our Galaxy,the Milky Way Galaxy?

Accepted Answer

A)  There are so many stars in our Galaxy that the more distant ones are hidden behind the nearer ones. 
B)  Distant stars are obscured by dust in interstellar space. 
C)  Expansion of the universe has carried the more distant stars out of our view. 
D)  Distant stars are obscured by gas in interstellar space. 
A)  There are so many stars in our Galaxy that the more distant ones are hidden behind the nearer ones. 
B)  Distant stars are obscured by dust in interstellar space. 
C)  Expansion of the universe has carried the more distant stars out of our view. 
D)  Distant stars are obscured by gas in interstellar space.

Variable stars,such as Cepheid variables and RR Lyrae stars,are used in what important measurement in astronomy?

How is the mass of the Galaxy estimated?

When distances were carefully measured from Earth to globular clusters above and below the Milky Way plane (where our view of them is not obscured by interstellar dust and gas),their distribution was found to be

Cepheid stars are useful to astronomers as indicators of

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

If the Galaxy were spinning like our solar system,stars farther out from the center would

The 21-cm emission is used mainly to map out globular clusters around the Galaxy.

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

If the Galaxy were spinning like a solid disk,stars farther out from the center would

Where in the Milky Way would you expect most star formation to be taking place?

In determining the distance to a galaxy by using observations of a Cepheid variable star,which of the following is NOT needed?

What evidence now exists for a supermassive black hole at the center of our Galaxy?

What is the evidence that indicates to some astronomers that a supermassive black hole exists at the center of our Galaxy?

In the self-propagating star formation theory,

Halo stars and globular clusters move in orbits that are oriented at random angles to the plane of the disk of a galaxy.

Stars in the disk of the Galaxy are mostly old,metal-poor,Population II stars.

Which of the following components of the Galaxy best outline the spiral arms of the Galaxy?

The Milky Way is an irregular galaxy.

The halo of the Galaxy is a spherical distribution that is traced by globular clusters.

Why are we able to see only a small part of our Galaxy,the Milky Way Galaxy?

Predicting the Motions of the Stars, Sun, and Moon

Decoding the Hidden Messages in Starlight

Analyzing Scales and Motions of the Universe

Exploring Our Evolving Solar System

Uncovering Earths Systems

Exploring Terrestrial Surface Processes and Atmospheres

Observing the Dynamic Giant Planets

Looking for Life Beyond Earth

Probing the Dynamic Sun

Observing Properties of Distant Stars

Inferring Patterns in Star Life Cycles

Predicting the Violent End of the Largest Stars

Investigating Other Galaxies

Observing the Evolution of the Universe

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Exam 13: Exploring Our Galaxy

Variable stars,such as Cepheid variables and RR Lyrae stars,are used in what important measurement in astronomy?

How is the mass of the Galaxy estimated?

When distances were carefully measured from Earth to globular clusters above and below the Milky Way plane (where our view of them is not obscured by interstellar dust and gas),their distribution was found to be

Cepheid stars are useful to astronomers as indicators of

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

If the Galaxy were spinning like our solar system,stars farther out from the center would

The 21-cm emission is used mainly to map out globular clusters around the Galaxy.

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

If the Galaxy were spinning like a solid disk,stars farther out from the center would

Where in the Milky Way would you expect most star formation to be taking place?

In determining the distance to a galaxy by using observations of a Cepheid variable star,which of the following is NOT needed?

What evidence now exists for a supermassive black hole at the center of our Galaxy?

What is the evidence that indicates to some astronomers that a supermassive black hole exists at the center of our Galaxy?

In the self-propagating star formation theory,

Halo stars and globular clusters move in orbits that are oriented at random angles to the plane of the disk of a galaxy.

Stars in the disk of the Galaxy are mostly old,metal-poor,Population II stars.

Which of the following components of the Galaxy best outline the spiral arms of the Galaxy?

The Milky Way is an irregular galaxy.

The halo of the Galaxy is a spherical distribution that is traced by globular clusters.

Why are we able to see only a small part of our Galaxy,the Milky Way Galaxy?

Predicting the Motions of the Stars, Sun, and Moon

Decoding the Hidden Messages in Starlight

Analyzing Scales and Motions of the Universe

Exploring Our Evolving Solar System

Uncovering Earths Systems

Exploring Terrestrial Surface Processes and Atmospheres

Observing the Dynamic Giant Planets

Looking for Life Beyond Earth

Probing the Dynamic Sun

Observing Properties of Distant Stars

Inferring Patterns in Star Life Cycles

Predicting the Violent End of the Largest Stars

Investigating Other Galaxies

Observing the Evolution of the Universe

Filters