Question 1

Red and orange stars are found evenly spread throughout the galactic disk, but blue stars are typically found ________.

Accepted Answer

A)  only in or near star-forming clouds 
B)  in the halo 
C)  only in the central bulge 
D)  also evenly spread throughout the galactic disk 
A)  only in or near star-forming clouds 
B)  in the halo 
C)  only in the central bulge 
D)  also evenly spread throughout the galactic disk

Question 2

Where do most dust grains form?

Accepted Answer

A)  in supernovae 
B)  in the winds of red giant stars 
C)  in planetary nebulae 
D)  in molecular clouds 
E)  all of the above 
A)  in supernovae 
B)  in the winds of red giant stars 
C)  in planetary nebulae 
D)  in molecular clouds 
E)  all of the above

Question 3

Briefly describe how we can use the orbital characteristics of stars at many distances from the galactic center to determine the distribution of mass in the Milky Way.

Accepted Answer

Using the orbital velocity law, related

Question 4

How did star formation likely proceed in the protogalactic cloud that formed the Milky Way?

Accepted Answer

A)  The stars that formed first could orbit the center of the galaxy in any direction at any inclination. 
B)  The stars that formed first eventually settled into a galactic disk, circling the center of the galaxy. 
C)  The protogalactic cloud gradually formed stars, starting from the center of the galaxy working outwards. 
D)  The protogalactic cloud gradually formed stars, starting from the outer edges of the spiral arms and working inward. 
A)  The stars that formed first could orbit the center of the galaxy in any direction at any inclination. 
B)  The stars that formed first eventually settled into a galactic disk, circling the center of the galaxy. 
C)  The protogalactic cloud gradually formed stars, starting from the center of the galaxy working outwards. 
D)  The protogalactic cloud gradually formed stars, starting from the outer edges of the spiral arms and working inward.

Question 5

We can see most of the Milky Way with visible light.

Accepted Answer

A) True 
 B)False

Question 6

All heavy elements are made during supernova explosions.

Accepted Answer

A) True 
 B)False

Question 7

Most of the mass of the galaxy is located at the galactic center in the form of a massive black hole.

Accepted Answer

A) True 
 B)False

Question 8

What affects the average orbital speed of a star in our galaxy?

Accepted Answer

A)  The mass of the galaxy inside its orbit and size of its orbit 
B)  The mass and age of the star 
C)  The star's mass and the mass of the galaxy 
D)  The mass and age of the galaxy 
A)  The mass of the galaxy inside its orbit and size of its orbit 
B)  The mass and age of the star 
C)  The star's mass and the mass of the galaxy 
D)  The mass and age of the galaxy

Question 9

Modified Newtonian Dynamics? The case for dark matter in the Milky Way can be viewed as a failure of stars and gas far from the galactic center to obey Newton's law of gravitational attraction-- that is, the stars and gas seem to orbit too quickly for the visible matter their orbits enclose. Why do you think that astronomers choose to "save" Newton's form of gravitational attraction by postulating unseen dark matter, as opposed to regarding the observed orbital motion as a falsification of Newtonian gravitation on the scale of the Milky Way? [Note: At the distance scales involved, the gravitational forces in the galaxy are all fairly weak, much weaker than those encountered in a neutron star or black hole, and hence Einstein's theory of gravity (General Relativity) gives the same predictions as Newton's gravitational law].

Accepted Answer

The question you've posed touches on a s

Question 10

Which of the following models best explains why our galaxy has spiral arms?

Accepted Answer

A)  The spiral arms are a wave of star formation caused by wave of density propagating outward through the disk of the galaxy. 
B)  The spiral arms are composed of groups of stars that are bound together by gravity and therefore always stay together as the galaxy rotates. 
C)  The spiral arms were imprinted on the galaxy at its birth. Ever since, like a coiling rope, the spiral arms have been wound tighter with each galactic rotation. 
D)  No model can explain the existence of the arms, which rotate with the galaxy like the fins of a giant pinwheel toy. 
A)  The spiral arms are a wave of star formation caused by wave of density propagating outward through the disk of the galaxy. 
B)  The spiral arms are composed of groups of stars that are bound together by gravity and therefore always stay together as the galaxy rotates. 
C)  The spiral arms were imprinted on the galaxy at its birth. Ever since, like a coiling rope, the spiral arms have been wound tighter with each galactic rotation. 
D)  No model can explain the existence of the arms, which rotate with the galaxy like the fins of a giant pinwheel toy.

Question 11

How would you expect a star that formed recently in the disk of the galaxy to differ from one that formed early in the history of the disk?

Accepted Answer

A)  It should have a higher fraction of elements heavier than hydrogen and helium. 
B)  It should be higher in mass. 
C)  It should be much brighter. 
D)  It should orbit the galactic center at a much higher rate of speed. 
E)  All of the above would be expected. 
A)  It should have a higher fraction of elements heavier than hydrogen and helium. 
B)  It should be higher in mass. 
C)  It should be much brighter. 
D)  It should orbit the galactic center at a much higher rate of speed. 
E)  All of the above would be expected.

Question 12

What is the diameter of the disk of the Milky Way?

Accepted Answer

A)  100 light years 
B)  1,000 light years 
C)  10,000 light years 
D)  100,000 light years 
E)  1,000,000 light years 
A)  100 light years 
B)  1,000 light years 
C)  10,000 light years 
D)  100,000 light years 
E)  1,000,000 light years

Question 13

What kinds of objects lie in the halo of our galaxy?

Accepted Answer

A)  open clusters 
B)  O and B stars 
C)  globular clusters 
D)  gas and dust 
E)  all of the above 
A)  open clusters 
B)  O and B stars 
C)  globular clusters 
D)  gas and dust 
E)  all of the above

Question 14

How does the interstellar medium obscure our view of most of the galaxy?

Accepted Answer

A)  Hydrogen gas produces so much visible light that the interstellar medium is opaque, blocking our view of anything beyond it. 
B)  Dust reflects most light from distant regions of the galaxy back towards the source. 
C)  Molecules in the interstellar medium absorb all wavelengths of light. 
D)  The small mixture of dust grains in the interstellar medium absorbs visible light. 
E)  all of the above 
A)  Hydrogen gas produces so much visible light that the interstellar medium is opaque, blocking our view of anything beyond it. 
B)  Dust reflects most light from distant regions of the galaxy back towards the source. 
C)  Molecules in the interstellar medium absorb all wavelengths of light. 
D)  The small mixture of dust grains in the interstellar medium absorbs visible light. 
E)  all of the above

Question 15

How do we learn about the conditions at the center of our own galaxy, the Milky Way?

Accepted Answer

A)  High-resolution photographs obtained by the Hubble Space Telescope have revealed the galactic center using visible light. 
B)  While we cannot see the galactic center with visible or ultraviolet light, radio and X-rays from the center can be detected and used to determine the conditions there. 
C)  The gas and dust in the Milky Way prevent any type of direct observation of the galactic center, but theoretical models allow us to predict what is happening there. 
D)  We must look at the centers of other (external) galaxies and assume that they are similar to the Milky Way. 
A)  High-resolution photographs obtained by the Hubble Space Telescope have revealed the galactic center using visible light. 
B)  While we cannot see the galactic center with visible or ultraviolet light, radio and X-rays from the center can be detected and used to determine the conditions there. 
C)  The gas and dust in the Milky Way prevent any type of direct observation of the galactic center, but theoretical models allow us to predict what is happening there. 
D)  We must look at the centers of other (external) galaxies and assume that they are similar to the Milky Way.

Question 16

Where are most heavy elements made?

Accepted Answer

A)  In the interstellar medium 
B)  In stars and supernovae 
C)  All were made in the Big Bang, when the universe first began 
D)  None of the above 
E)  All of the above 
A)  In the interstellar medium 
B)  In stars and supernovae 
C)  All were made in the Big Bang, when the universe first began 
D)  None of the above 
E)  All of the above

Question 17

What are the Magellanic Clouds?

Accepted Answer

A)  Two small galaxies that orbit the Milky Way Galaxy 
B)  Two nebulae located in the disk of the Milky Way galaxy and visible only from the Southern Hemisphere 
C)  Star-forming clouds found in the constellation Orion 
D)  The clouds of dust and gas found interspersed in many places throughout the Milky Way Galaxy 
A)  Two small galaxies that orbit the Milky Way Galaxy 
B)  Two nebulae located in the disk of the Milky Way galaxy and visible only from the Southern Hemisphere 
C)  Star-forming clouds found in the constellation Orion 
D)  The clouds of dust and gas found interspersed in many places throughout the Milky Way Galaxy

Question 18

Why do stars in the disk of a spiral galaxy orbit in roughly the same direction, in the same plane in space?

Accepted Answer

A)  It is pure coincidence; the stars just happen to be going in the same direction. 
B)  The gas that formed the stars was shaped as a giant, rotating disk. 
C)  Collisions between the stars caused their motions to organize into a general, spinning disk direction. 
D)  After the stars formed, gravity pulled the stars down into a plane in space, all orbiting a supermassive black hole. 
A)  It is pure coincidence; the stars just happen to be going in the same direction. 
B)  The gas that formed the stars was shaped as a giant, rotating disk. 
C)  Collisions between the stars caused their motions to organize into a general, spinning disk direction. 
D)  After the stars formed, gravity pulled the stars down into a plane in space, all orbiting a supermassive black hole.

Question 19

What makes up the interstellar medium?

Accepted Answer

A)  open clusters 
B)  O and B stars 
C)  K and M stars 
D)  gas and dust 
E)  all of the above 
A)  open clusters 
B)  O and B stars 
C)  K and M stars 
D)  gas and dust 
E)  all of the above

Question 20

The Sun's location in the Milky Way Galaxy is ________.

Accepted Answer

A)  very near the galactic center 
B)  in the galactic disk, roughly halfway between the center and the outer edge of the disk 
C)  in the halo of the galaxy, about 28,000 light-years above the galactic disk 
D)  at the very outer edge of the galactic disk 
A)  very near the galactic center 
B)  in the galactic disk, roughly halfway between the center and the outer edge of the disk 
C)  in the halo of the galaxy, about 28,000 light-years above the galactic disk 
D)  at the very outer edge of the galactic disk

Red and orange stars are found evenly spread throughout the galactic disk, but blue stars are typically found ________.

Where do most dust grains form?

Briefly describe how we can use the orbital characteristics of stars at many distances from the galactic center to determine the distribution of mass in the Milky Way.

How did star formation likely proceed in the protogalactic cloud that formed the Milky Way?

We can see most of the Milky Way with visible light.

All heavy elements are made during supernova explosions.

Most of the mass of the galaxy is located at the galactic center in the form of a massive black hole.

What affects the average orbital speed of a star in our galaxy?

Which of the following models best explains why our galaxy has spiral arms?

How would you expect a star that formed recently in the disk of the galaxy to differ from one that formed early in the history of the disk?

What is the diameter of the disk of the Milky Way?

What kinds of objects lie in the halo of our galaxy?

How does the interstellar medium obscure our view of most of the galaxy?

How do we learn about the conditions at the center of our own galaxy, the Milky Way?

Where are most heavy elements made?

What are the Magellanic Clouds?

Why do stars in the disk of a spiral galaxy orbit in roughly the same direction, in the same plane in space?

What makes up the interstellar medium?

The Sun's location in the Milky Way Galaxy is ________.

Our Place in the Universe

Discovering the Universe for Yourself

The Science of Astronomy

Making Sense of the Universe: Understanding Motion, Energy, and Gravity

Light: the Cosmic Messenger

Formation of Planetary Systems: Our Solar System and Beyond

Earth and the Terrestrial Worlds

Jovian Planet Systems

Asteroids, Comets, and Dwarf Planets: Their Nature, Orbits, and Impacts

Our Star

Surveying the Stars

Star Stuff

Bizarre Stellar Graveyard

Galaxies and the Foundation of Modern Cosmology

Dark Matter, Dark Energy, and the Fate of the Universe

The Beginning of Time

Life in the Universe

Filters

Exam 14: Our Galaxy

Red and orange stars are found evenly spread throughout the galactic disk, but blue stars are typically found ________.

Where do most dust grains form?

Briefly describe how we can use the orbital characteristics of stars at many distances from the galactic center to determine the distribution of mass in the Milky Way.

How did star formation likely proceed in the protogalactic cloud that formed the Milky Way?

We can see most of the Milky Way with visible light.

All heavy elements are made during supernova explosions.

Most of the mass of the galaxy is located at the galactic center in the form of a massive black hole.

What affects the average orbital speed of a star in our galaxy?

Which of the following models best explains why our galaxy has spiral arms?

How would you expect a star that formed recently in the disk of the galaxy to differ from one that formed early in the history of the disk?

What is the diameter of the disk of the Milky Way?

What kinds of objects lie in the halo of our galaxy?

How does the interstellar medium obscure our view of most of the galaxy?

How do we learn about the conditions at the center of our own galaxy, the Milky Way?

Where are most heavy elements made?

What are the Magellanic Clouds?

Why do stars in the disk of a spiral galaxy orbit in roughly the same direction, in the same plane in space?

What makes up the interstellar medium?

The Sun's location in the Milky Way Galaxy is ________.

Our Place in the Universe

Discovering the Universe for Yourself

The Science of Astronomy

Making Sense of the Universe: Understanding Motion, Energy, and Gravity

Light: the Cosmic Messenger

Formation of Planetary Systems: Our Solar System and Beyond

Earth and the Terrestrial Worlds

Jovian Planet Systems

Asteroids, Comets, and Dwarf Planets: Their Nature, Orbits, and Impacts

Our Star

Surveying the Stars

Star Stuff

Bizarre Stellar Graveyard

Galaxies and the Foundation of Modern Cosmology

Dark Matter, Dark Energy, and the Fate of the Universe

The Beginning of Time

Life in the Universe

Filters