Question 1

The center of the Milky Way was an active galactic nucleus in the past.What direct observational evidence supports this?

Accepted Answer

A)  gamma-ray bubbles extending thousands of light-years above and below the galactic plane 
B)  rapid motions of stars near the galactic center 
C)  X-ray emission near the galactic center 
D)  All of the above. 
A)  gamma-ray bubbles extending thousands of light-years above and below the galactic plane 
B)  rapid motions of stars near the galactic center 
C)  X-ray emission near the galactic center 
D)  All of the above.

Question 2

How do we know that globular cluster stars were not the first stars that formed in our galaxy?

Accepted Answer

They contain some massive elem

Question 3

Harlow Shapley showed that ________ form a spherical halo that is not centered on the Solar System,disproving the idea that the Sun was the center of the Milky Way Galaxy.

Accepted Answer

A)  21-cm emission from neutral hydrogen gas 
B)  globular clusters 
C)  open clusters 
D)  X-ray-emitting hot gas 
A)  21-cm emission from neutral hydrogen gas 
B)  globular clusters 
C)  open clusters 
D)  X-ray-emitting hot gas

Question 4

How does the H-R diagram of an open cluster show that its age is very young? Provide a sketch of an H-R diagram for an open cluster.

Accepted Answer

The cluster contains very hot

Question 5

Why do we know that at least one generation of stars formed and died before the Milky Way's globular clusters formed?

Accepted Answer

A)  All globular clusters reside in the disk of the Milky Way. 
B)  No globular cluster has zero heavy elements. 
C)  Globular clusters are 9 billion to 10 billion years old. 
D)  No globular cluster is older than 12 billion years. 
A)  All globular clusters reside in the disk of the Milky Way. 
B)  No globular cluster has zero heavy elements. 
C)  Globular clusters are 9 billion to 10 billion years old. 
D)  No globular cluster is older than 12 billion years.

Question 6

In a star that has a chemical abundance similar to the Sun,what percentage of its mass is made of heavy elements?

Accepted Answer

A)  0.02 percent 
B)  0.2 percent 
C)  2 percent 
D)  20 percent 
A)  0.02 percent 
B)  0.2 percent 
C)  2 percent 
D)  20 percent

Question 7

Describe a scale model of the disk of the Milky Way using a scale in which 1 cm = 1,000 light-years.Note that the diameter of the disk is approximately 100,000 light-years,the thickness of young stars is 500 light-years,and the thickness of the older stars is 4,000 light-years.

Accepted Answer

In this model,the disk would be 1 meter

Question 8

How have astronomers measured the mass of the black hole at the center of our galaxy?

Accepted Answer

A)  using the rotation curve derived from 21-cm emission 
B)  by observing the motions of stars near the center of the galaxy 
C)  by measuring the brightness of the quasar 
D)  by measuring the Doppler shift of Sagittarius A* 
A)  using the rotation curve derived from 21-cm emission 
B)  by observing the motions of stars near the center of the galaxy 
C)  by measuring the brightness of the quasar 
D)  by measuring the Doppler shift of Sagittarius A*

Question 9

Our Milky Way Galaxy shares the following property in common with other galaxies.

Accepted Answer

A)  Most of the mass in our galaxy is in the form of dark matter. 
B)  Most of the mass in our galaxy is in the form of dust. 
C)  Most of the mass in our galaxy is in the form of hydrogen. 
D)  Most of the mass in our galaxy is in the form of stars. 
A)  Most of the mass in our galaxy is in the form of dark matter. 
B)  Most of the mass in our galaxy is in the form of dust. 
C)  Most of the mass in our galaxy is in the form of hydrogen. 
D)  Most of the mass in our galaxy is in the form of stars.

Question 10

Most of the mass in our galaxy is in the form of:

Accepted Answer

A)  stars 
B)  gas 
C)  dust 
D)  dark matter 
A)  stars 
B)  gas 
C)  dust 
D)  dark matter

Question 11

Which of the following statements is NOT a property of a globular cluster?

Accepted Answer

A)  consists of hundreds of thousands of stars 
B)  contains old stars 
C)  loosely gravitationally bound 
D)  tightly gravitationally bound 
A)  consists of hundreds of thousands of stars 
B)  contains old stars 
C)  loosely gravitationally bound 
D)  tightly gravitationally bound

Question 12

The Milky Way is part of the Local Group of galaxies.Which of the following statements best describes the Local Group?

Accepted Answer

A)  a vast network of thousands of galaxies 
B)  the Milky Way and its orbiting companion galaxies 
C)  about 50 galaxies, including Andromeda and many dwarf galaxies 
D)  the Milky Way and its halo of globular clusters 
A)  a vast network of thousands of galaxies 
B)  the Milky Way and its orbiting companion galaxies 
C)  about 50 galaxies, including Andromeda and many dwarf galaxies 
D)  the Milky Way and its halo of globular clusters

Question 13

Because of the ages of globular clusters in the Milky Way,we think our galaxy's early formation history was characterized by:

Accepted Answer

A)  one single cloud of gas gently collapsing and star formation proceeding slowly within it. 
B)  one single cloud of gas that rapidly collapsed and turned most of its gas into stars. 
C)  merging of protogalactic fragments that stimulated a high rate of star formation. 
D)  slow merging of protogalactic fragments after they had already turned most of their gas into stars. 
A)  one single cloud of gas gently collapsing and star formation proceeding slowly within it. 
B)  one single cloud of gas that rapidly collapsed and turned most of its gas into stars. 
C)  merging of protogalactic fragments that stimulated a high rate of star formation. 
D)  slow merging of protogalactic fragments after they had already turned most of their gas into stars.

Question 14

What is ripping apart the Sagittarius dwarf spheroidal galaxy?

Accepted Answer

A)  a supermassive black hole at its center 
B)  the energetic decay of a WIMP 
C)  a violent episode of star formation 
D)  the gravitational tidal force of the Milky Way 
A)  a supermassive black hole at its center 
B)  the energetic decay of a WIMP 
C)  a violent episode of star formation 
D)  the gravitational tidal force of the Milky Way

Question 15

Why can the observed chemical abundance of a star tell you something about its age?

Accepted Answer

As a galaxy evolves,gas is converted to

Question 16

Sketch an edge-on view of the Milky Way.Label the locations of the bulge,disk,and halo.

Accepted Answer

The sketch should show a flat

Question 17

Sagittarius A*,the radio source located at the center of our galaxy,is believed to be a:

Accepted Answer

A)  massive star cluster. 
B)  supernova remnant. 
C)  quasar. 
D)  supermassive black hole. 
A)  massive star cluster. 
B)  supernova remnant. 
C)  quasar. 
D)  supermassive black hole.

Question 18

Why is 21-cm radiation the best way to map the spiral arms in the Milky Way?

Accepted Answer

A)  The molecular hydrogen gas that produces this emission is concentrated in the spiral arms. 
B)  These photons, which are produced by neutral hydrogen, penetrate the dense clouds of gas and dust in the disk. 
C)  This synchrotron emission is produced by supernovae, which are concentrated in the spiral arms. 
D)  Radio telescopes are easier to operate than optical telescopes, and observations can be made even during the daytime. 
A)  The molecular hydrogen gas that produces this emission is concentrated in the spiral arms. 
B)  These photons, which are produced by neutral hydrogen, penetrate the dense clouds of gas and dust in the disk. 
C)  This synchrotron emission is produced by supernovae, which are concentrated in the spiral arms. 
D)  Radio telescopes are easier to operate than optical telescopes, and observations can be made even during the daytime.

Question 19

Where are the most metal-rich stars found in the Milky Way?

Accepted Answer

A)  in the disk near the Sun 
B)  at the center 
C)  in the halo 
D)  in globular clusters 
A)  in the disk near the Sun 
B)  at the center 
C)  in the halo 
D)  in globular clusters

Question 20

The fact that the Milky Way has orbiting companion galaxies and is currently "eating" one of them is evidence that:

Accepted Answer

A)  all galaxies are blueshifted with respect to the Milky Way. 
B)  galaxies form by mergers of smaller protogalaxies. 
C)  the Milky Way is the center of the universe. 
D)  we cannot learn anything from this evidence 
A)  all galaxies are blueshifted with respect to the Milky Way. 
B)  galaxies form by mergers of smaller protogalaxies. 
C)  the Milky Way is the center of the universe. 
D)  we cannot learn anything from this evidence

The center of the Milky Way was an active galactic nucleus in the past.What direct observational evidence supports this?

How do we know that globular cluster stars were not the first stars that formed in our galaxy?

Harlow Shapley showed that ________ form a spherical halo that is not centered on the Solar System,disproving the idea that the Sun was the center of the Milky Way Galaxy.

How does the H-R diagram of an open cluster show that its age is very young? Provide a sketch of an H-R diagram for an open cluster.

Why do we know that at least one generation of stars formed and died before the Milky Way's globular clusters formed?

In a star that has a chemical abundance similar to the Sun,what percentage of its mass is made of heavy elements?

Describe a scale model of the disk of the Milky Way using a scale in which 1 cm = 1,000 light-years.Note that the diameter of the disk is approximately 100,000 light-years,the thickness of young stars is 500 light-years,and the thickness of the older stars is 4,000 light-years.

How have astronomers measured the mass of the black hole at the center of our galaxy?

Our Milky Way Galaxy shares the following property in common with other galaxies.

Most of the mass in our galaxy is in the form of:

Which of the following statements is NOT a property of a globular cluster?

The Milky Way is part of the Local Group of galaxies.Which of the following statements best describes the Local Group?

Because of the ages of globular clusters in the Milky Way,we think our galaxy's early formation history was characterized by:

What is ripping apart the Sagittarius dwarf spheroidal galaxy?

Why can the observed chemical abundance of a star tell you something about its age?

Sketch an edge-on view of the Milky Way.Label the locations of the bulge,disk,and halo.

Sagittarius A*,the radio source located at the center of our galaxy,is believed to be a:

Why is 21-cm radiation the best way to map the spiral arms in the Milky Way?

Where are the most metal-rich stars found in the Milky Way?

The fact that the Milky Way has orbiting companion galaxies and is currently "eating" one of them is evidence that:

Thinking Like an Astronomer

Patterns in the Skymotions of Earth and the Moon

Laws of Motion

Light and Telescopes

The Formation of Stars and Planets

Terrestrial Worlds in the Inner Solar System

Atmospheres of Venus, earth, and Mars

The Giant Planets

Small Bodies of the Solar System

Measuring the Stars

Our Star: the Sun

Evolution of Low-Mass Stars

Evolution of High-Mass Stars

Measuring Galaxies

The Evolution of the Universe

Formation of Structure

Life in the Universe

Filters

Exam 15: Our Galaxy: the Milky Way

The center of the Milky Way was an active galactic nucleus in the past.What direct observational evidence supports this?

How do we know that globular cluster stars were not the first stars that formed in our galaxy?

Harlow Shapley showed that ________ form a spherical halo that is not centered on the Solar System,disproving the idea that the Sun was the center of the Milky Way Galaxy.

How does the H-R diagram of an open cluster show that its age is very young? Provide a sketch of an H-R diagram for an open cluster.

Why do we know that at least one generation of stars formed and died before the Milky Way's globular clusters formed?

In a star that has a chemical abundance similar to the Sun,what percentage of its mass is made of heavy elements?

Describe a scale model of the disk of the Milky Way using a scale in which 1 cm = 1,000 light-years.Note that the diameter of the disk is approximately 100,000 light-years,the thickness of young stars is 500 light-years,and the thickness of the older stars is 4,000 light-years.

How have astronomers measured the mass of the black hole at the center of our galaxy?

Our Milky Way Galaxy shares the following property in common with other galaxies.

Most of the mass in our galaxy is in the form of:

Which of the following statements is NOT a property of a globular cluster?

The Milky Way is part of the Local Group of galaxies.Which of the following statements best describes the Local Group?

Because of the ages of globular clusters in the Milky Way,we think our galaxy's early formation history was characterized by:

What is ripping apart the Sagittarius dwarf spheroidal galaxy?

Why can the observed chemical abundance of a star tell you something about its age?

Sketch an edge-on view of the Milky Way.Label the locations of the bulge,disk,and halo.

Sagittarius A*,the radio source located at the center of our galaxy,is believed to be a:

Why is 21-cm radiation the best way to map the spiral arms in the Milky Way?

Where are the most metal-rich stars found in the Milky Way?

The fact that the Milky Way has orbiting companion galaxies and is currently "eating" one of them is evidence that:

Thinking Like an Astronomer

Patterns in the Skymotions of Earth and the Moon

Laws of Motion

Light and Telescopes

The Formation of Stars and Planets

Terrestrial Worlds in the Inner Solar System

Atmospheres of Venus, earth, and Mars

The Giant Planets

Small Bodies of the Solar System

Measuring the Stars

Our Star: the Sun

Evolution of Low-Mass Stars

Evolution of High-Mass Stars

Measuring Galaxies

The Evolution of the Universe

Formation of Structure

Life in the Universe

Filters