Question 1

A "galactic year" as defined by astronomers is:

Accepted Answer

A)  the time it takes the Earth to go around the Sun (starting with when it's closest in its orbit to the center of the Galaxy) 
B)  the time it takes the outermost part of the solar system (the Oort Cloud) to rotate once relative to the Galaxy) 
C)  the time it took the Milky Way Galaxy to develop spiral arms 
D)  the time it takes the Sun to revolve once around the center of the Milky Way Galaxy 
E)  the time it will take the Sun to become a red giant and expand into the Galaxy 
A)  the time it takes the Earth to go around the Sun (starting with when it's closest in its orbit to the center of the Galaxy) 
B)  the time it takes the outermost part of the solar system (the Oort Cloud) to rotate once relative to the Galaxy) 
C)  the time it took the Milky Way Galaxy to develop spiral arms 
D)  the time it takes the Sun to revolve once around the center of the Milky Way Galaxy 
E)  the time it will take the Sun to become a red giant and expand into the Galaxy

Question 2

You suddenly get an uncontrollable urge to find out more about the other side of the Milky Way Galaxy (the regions beyond the center). Where should you rush off to?

Accepted Answer

A)  the control room of the Hubble Space Telescope at NASA 
B)  a radio telescope that can observe at 21-cm wavelengths 
C)  the control room of the Compton Gamma-Ray Observatory 
D)  a gold mine near Lead, South Dakota 
E)  the same factory that makes Snickers candy bars 
A)  the control room of the Hubble Space Telescope at NASA 
B)  a radio telescope that can observe at 21-cm wavelengths 
C)  the control room of the Compton Gamma-Ray Observatory 
D)  a gold mine near Lead, South Dakota 
E)  the same factory that makes Snickers candy bars

Question 3

The Population I stars in the Milky Way Galaxy

Accepted Answer

A)  include the Sun 
B)  show a wider range of ages than Population II stars 
C)  generally contain a greater percentage of heavier elements than Population II stars 
D)  are generally found in the disk of the Galaxy 
E)  all of the above
Section 25.6: The Formation of the Galaxy 
A)  include the Sun 
B)  show a wider range of ages than Population II stars 
C)  generally contain a greater percentage of heavier elements than Population II stars 
D)  are generally found in the disk of the Galaxy 
E)  all of the above
Section 25.6: The Formation of the Galaxy

Question 4

What have we learned from the work of Harlow Shapley and others about the location of the Sun in the Milky Way Galaxy?

Accepted Answer

A)  we are almost exactly in the center of a giant flat pinwheel 
B)  we are very close the edge of the visible disk of the Galaxy, more than 50,000 LY from the center 
C)  we are high above the disk of the Galaxy, about as far away as the most distant globular cluster 
D)  we are in the disk of the Galaxy, about 3/5 of the way from the center 
E)  you can't fool me; because of all the dust, astronomers still have no idea where our Sun is located in the Milky Way Galaxy 
A)  we are almost exactly in the center of a giant flat pinwheel 
B)  we are very close the edge of the visible disk of the Galaxy, more than 50,000 LY from the center 
C)  we are high above the disk of the Galaxy, about as far away as the most distant globular cluster 
D)  we are in the disk of the Galaxy, about 3/5 of the way from the center 
E)  you can't fool me; because of all the dust, astronomers still have no idea where our Sun is located in the Milky Way Galaxy

Question 5

An astronomer needs to measure the distance to a globular cluster of stars that is part of the Milky Way Galaxy. What method should she try to use to find the distance?

Accepted Answer

A)  measure the parallax of the cluster 
B)  count the number of O and B type stars in the cluster 
C)  look for flickering x-rays coming from a black hole in a binary star system in the cluster 
D)  measure the red-shift of the cluster 
E)  find a variable star (cepheid or RR Lyrae) in the cluster 
A)  measure the parallax of the cluster 
B)  count the number of O and B type stars in the cluster 
C)  look for flickering x-rays coming from a black hole in a binary star system in the cluster 
D)  measure the red-shift of the cluster 
E)  find a variable star (cepheid or RR Lyrae) in the cluster

Question 6

Astronomers believe that the center of our Galaxy has a black hole with enough mass inside to make almost 4 million Suns! How do astronomers think a black hole could acquire so much mass?

Accepted Answer

A)  the Galaxy formed from one supergiant star, and most of what is left of it is now in the black hole 
B)  the black hole at the center is really another galaxy that our Milky Way swallowed; none of its material comes from our own Galaxy 
C)  the center of our Galaxy is a much more crowded region than where the Sun is found; we still see material falling toward the center and material has fallen in for billions of years 
D)  this black hole contains only dark matter, and we know dark matter is concentrated toward the center of our Galaxy; none of it can be found near the outer regions of the Milky Way 
E)  no one can think of a way to make a black hole this massive; that's why most astronomers are skeptical about the observations that indicate that our Galaxy has such a black hole
Section 25.5: Stellar Populations in the Galaxy 
A)  the Galaxy formed from one supergiant star, and most of what is left of it is now in the black hole 
B)  the black hole at the center is really another galaxy that our Milky Way swallowed; none of its material comes from our own Galaxy 
C)  the center of our Galaxy is a much more crowded region than where the Sun is found; we still see material falling toward the center and material has fallen in for billions of years 
D)  this black hole contains only dark matter, and we know dark matter is concentrated toward the center of our Galaxy; none of it can be found near the outer regions of the Milky Way 
E)  no one can think of a way to make a black hole this massive; that's why most astronomers are skeptical about the observations that indicate that our Galaxy has such a black hole
Section 25.5: Stellar Populations in the Galaxy

Question 7

What objects did Harlow Shapley use as "signposts" to figure out the extent of the Milky Way Galaxy and the location of its center?

Accepted Answer

A)  thick clouds of cold hydrogen giving off 21-cm radiation 
B)  globular clusters 
C)  HII regions 
D)  dust clouds 
E)  big arches advertising "billions and billions sold" 
A)  thick clouds of cold hydrogen giving off 21-cm radiation 
B)  globular clusters 
C)  HII regions 
D)  dust clouds 
E)  big arches advertising "billions and billions sold"

Question 8

Which of the following statements about the nuclear bulge of our Galaxy is FALSE?

Accepted Answer

A)  it is significantly thicker than the disk of the Galaxy 
B)  it typically consists of older stars 
C)  it is difficult for us to see with visible light because of cosmic dust 
D)  the best way to learn more about it is to observe higher energy radiation, such as ultraviolet and x-rays 
E)  there is evidence that it is not exactly spherical, but elongated
Section 25.2: Spiral Structure 
A)  it is significantly thicker than the disk of the Galaxy 
B)  it typically consists of older stars 
C)  it is difficult for us to see with visible light because of cosmic dust 
D)  the best way to learn more about it is to observe higher energy radiation, such as ultraviolet and x-rays 
E)  there is evidence that it is not exactly spherical, but elongated
Section 25.2: Spiral Structure

Question 9

What was especially noteworthy about the Sagittarius Dwarf Galaxy when it was discovered among the small galaxies near the Milky Way?

Accepted Answer

A)  it was so large in mass, astronomers could not understand how the Milky Way wasn't flying toward it 
B)  it had a supermassive black hole in the center much larger than the Milky Way's 
C)  it was rotating so quickly that it could not hold together for very long 
D)  it was on a collision course with the Milky Way and would be swallowed by it eventually 
E)  it was made entirely of dark matter and so could not be seen on any photographs 
A)  it was so large in mass, astronomers could not understand how the Milky Way wasn't flying toward it 
B)  it had a supermassive black hole in the center much larger than the Milky Way's 
C)  it was rotating so quickly that it could not hold together for very long 
D)  it was on a collision course with the Milky Way and would be swallowed by it eventually 
E)  it was made entirely of dark matter and so could not be seen on any photographs

Question 10

The central region of our Galaxy is not as flat as its main disk of stars. Which of the following has roughly the same shape as our central region of stars?

Accepted Answer

A)  a peanut 
B)  a tennis ball 
C)  a cube 
D)  a long piece of string 
E)  actually, no one knows the shape of our central region because of all the dust in the Galaxy 
A)  a peanut 
B)  a tennis ball 
C)  a cube 
D)  a long piece of string 
E)  actually, no one knows the shape of our central region because of all the dust in the Galaxy

Question 11

How do astronomers measure the mass that the Galaxy contains inside the orbit of the Sun?

Accepted Answer

A)  they count the number of stars one by one and multiply by the average mass of a star 
B)  they add up all the observations at 21-cm wavelengths (because the mass of hydrogen gas is far greater than the mass in all the stars) 
C)  they measure the distance to the center of the Galaxy and the period of the Sun's orbit and then use Kepler's Third Law 
D)  they measure the masses of many other spiral galaxies nearby and then take an average 
E)  you can't fool me; there is no way to get the mass of something as big as our Galaxy 
A)  they count the number of stars one by one and multiply by the average mass of a star 
B)  they add up all the observations at 21-cm wavelengths (because the mass of hydrogen gas is far greater than the mass in all the stars) 
C)  they measure the distance to the center of the Galaxy and the period of the Sun's orbit and then use Kepler's Third Law 
D)  they measure the masses of many other spiral galaxies nearby and then take an average 
E)  you can't fool me; there is no way to get the mass of something as big as our Galaxy

Exam 25: The Milky Way Galaxy

A "galactic year" as defined by astronomers is:

You suddenly get an uncontrollable urge to find out more about the other side of the Milky Way Galaxy (the regions beyond the center). Where should you rush off to?

The Population I stars in the Milky Way Galaxy

What have we learned from the work of Harlow Shapley and others about the location of the Sun in the Milky Way Galaxy?

An astronomer needs to measure the distance to a globular cluster of stars that is part of the Milky Way Galaxy. What method should she try to use to find the distance?

Astronomers believe that the center of our Galaxy has a black hole with enough mass inside to make almost 4 million Suns! How do astronomers think a black hole could acquire so much mass?

What objects did Harlow Shapley use as "signposts" to figure out the extent of the Milky Way Galaxy and the location of its center?

Which of the following statements about the nuclear bulge of our Galaxy is FALSE?

What was especially noteworthy about the Sagittarius Dwarf Galaxy when it was discovered among the small galaxies near the Milky Way?

The central region of our Galaxy is not as flat as its main disk of stars. Which of the following has roughly the same shape as our central region of stars?

How do astronomers measure the mass that the Galaxy contains inside the orbit of the Sun?

Science and the Universe: a Brief Tour

Observing the Sky: the Birth of Astronomy

Orbits and Gravity

Earth, Moon, and Sky

Radiation and Spectra

Astronomical Instruments

Other Worlds: an Introduction to the Solar System

Earth As a Planet

Cratered Worlds: the Moon and Mercury

Earthlike Planets: Venus and Mars

The Giant Planets

Rings, Moons, and Pluto

Comets and Asteroids: Debris of the Solar System

Cosmic Samples and the Origin of the Solar System

The Sun: a Garden-Variety Star

The Sun: a Nuclear Powerhouse

Analyzing Starlight

The Stars: a Celestial Census

Celestial Distances

Between the Stars

The Birth of Stars and the Discovery of Planets Outside the Solar System

Stars From Adolescence to Old Age

The Death of Stars

Black Holes and Curved Space-Time

Galaxies

Active Galaxies, Quasars, and Supermassive Black Holes

The Evolution and Distribution of Galaxies

The Big Bang

Life in the Universe

Filters