Question 1

The distance of the Sun from the galactic center is considered to be around what value?

Accepted Answer

A) 2.5 kpc 
B) 5.2 kpc 
C) 8.5 kpc 
D) 9.3 kpc 
A) 2.5 kpc 
B) 5.2 kpc 
C) 8.5 kpc 
D) 9.3 kpc

Question 2

We cannot see the other side of the galaxy primarily because our view is blocked by

Accepted Answer

A) Too many stars 
B) Glowing interstellar gas 
C) Interstellar dust 
D) Planetary nebulae and supernova remnants 
A) Too many stars 
B) Glowing interstellar gas 
C) Interstellar dust 
D) Planetary nebulae and supernova remnants

Question 3

Why are HII regions red in color?

Accepted Answer

A) They contain considerable quantities of dust 
B) They emit hydrogen emission lines 
C) They are moving away from us at high speed 
D) Twenty-one cm photons are red in color 
A) They contain considerable quantities of dust 
B) They emit hydrogen emission lines 
C) They are moving away from us at high speed 
D) Twenty-one cm photons are red in color

Question 4

Which of the following statements about the density wave model for spiral arms is FALSE?

Accepted Answer

A) Material,once it enters a spiral arm,remains there permanently 
B) Star formation occurs in spiral arms 
C) Once started,spiral structure lasts a long time 
D) Spiral arms are not winding up as time passes 
A) Material,once it enters a spiral arm,remains there permanently 
B) Star formation occurs in spiral arms 
C) Once started,spiral structure lasts a long time 
D) Spiral arms are not winding up as time passes

Question 5

What assumption about globular clusters did Harlow Shapley make in order to determine the location of and distance to the center of the Milky Way?

Accepted Answer

A) The globular clusters are distributed about the center of the Milky Way 
B) All globular clusters have the same age 
C) All globular clusters are moving away from us 
D) None of the clusters we see are located in the Milky Way 
A) The globular clusters are distributed about the center of the Milky Way 
B) All globular clusters have the same age 
C) All globular clusters are moving away from us 
D) None of the clusters we see are located in the Milky Way

Question 6

How do we know that the Milky Way has a spiral structure?

Accepted Answer

A) By plotting the distances and directions of objects known to be in spiral arms 
B) By viewing the galaxy from a point well above its plane 
C) By observing the changing conditions as the sun enters a spiral arm 
D) By observing the gravitational influence of the arms on nearby galaxies 
A) By plotting the distances and directions of objects known to be in spiral arms 
B) By viewing the galaxy from a point well above its plane 
C) By observing the changing conditions as the sun enters a spiral arm 
D) By observing the gravitational influence of the arms on nearby galaxies

Question 7

Which of the following best describes the way that our galaxy has changed throughout its history?

Accepted Answer

A) It has grown flatter and richer in heavy elements 
B) It has grown less flattened and richer in heavy elements 
C) It has grown flatter and poorer in heavy elements 
D) It has grown less flattened and poorer in heavy elements 
A) It has grown flatter and richer in heavy elements 
B) It has grown less flattened and richer in heavy elements 
C) It has grown flatter and poorer in heavy elements 
D) It has grown less flattened and poorer in heavy elements

Question 8

Our Milky Way Galaxy is considered to have how many main spiral arms?

Accepted Answer

A) 1 
B) 2 
C) 4 
D) 6 
A) 1 
B) 2 
C) 4 
D) 6

Question 9

Astronomers of about the year 1900 didn't know of the existence of interstellar dust.As a result they

Accepted Answer

A) Underestimated the size of the galaxy. 
B) Thought the globular clusters were located in other galaxies 
C) Did not believe that our galaxy had spiral arms 
D) Believed stars were much bluer than they really are 
A) Underestimated the size of the galaxy. 
B) Thought the globular clusters were located in other galaxies 
C) Did not believe that our galaxy had spiral arms 
D) Believed stars were much bluer than they really are

Question 10

The hydrogen in an HII region is

Accepted Answer

A) In molecular form 
B) Very cool 
C) Ionized 
D) In liquid form 
A) In molecular form 
B) Very cool 
C) Ionized 
D) In liquid form

Question 11

Which of the following statements describes the mass in the outer part of the Milky Way (beyond the orbit of the sun)?

Accepted Answer

A) It emits a surprisingly small amount of light 
B) There is essentially no mass out there 
C) There is no spiral arm structure in the outer galaxy 
D) The outer part of the galaxy is rapidly evaporating into intergalactic space 
A) It emits a surprisingly small amount of light 
B) There is essentially no mass out there 
C) There is no spiral arm structure in the outer galaxy 
D) The outer part of the galaxy is rapidly evaporating into intergalactic space

Question 12

Which of the following must be known in order to determine the amount of galactic mass that lies within the Sun's orbit?

Accepted Answer

A) The Sun's distance from the center and orbital period 
B) The Sun's mass and orbital speed 
C) The Sun's distance from the center and the size of its orbit 
D) The Sun's mass and its distance from the center 
A) The Sun's distance from the center and orbital period 
B) The Sun's mass and orbital speed 
C) The Sun's distance from the center and the size of its orbit 
D) The Sun's mass and its distance from the center

Question 13

The distance to the center of our galaxy can be found from

Accepted Answer

A) The Cepheid variables there 
B) The parallax of the black hole located there 
C) Radar measurements 
D) The distribution of globular clusters in space 
A) The Cepheid variables there 
B) The parallax of the black hole located there 
C) Radar measurements 
D) The distribution of globular clusters in space

Question 14

Which of the following is the best description of the rotation curve of the galaxy between the Sun's orbital distance and twice the Sun's orbital distance?

Accepted Answer

A) Flat 
B) Rising steadily 
C) Falling steadily 
D) Many large fluctuations in orbital speed with distance 
A) Flat 
B) Rising steadily 
C) Falling steadily 
D) Many large fluctuations in orbital speed with distance

Question 15

Which of the following is an example of population II?

Accepted Answer

A) A supernova 
B) A globular cluster 
C) An HII region 
D) A molecular cloud 
A) A supernova 
B) A globular cluster 
C) An HII region 
D) A molecular cloud

Question 16

The galaxy has become enriched in heavy elements since it formed.What is responsible for the enrichment?

Accepted Answer

A) Nuclear reactions in interstellar clouds 
B) The infall of heavy elements from intergalactic space 
C) The transformation of cosmic rays into heavy elements 
D) Nuclear reactions in stars,followed by stellar mass loss 
A) Nuclear reactions in interstellar clouds 
B) The infall of heavy elements from intergalactic space 
C) The transformation of cosmic rays into heavy elements 
D) Nuclear reactions in stars,followed by stellar mass loss

Question 17

Which of the following is evidence for violent activity at the center of the galaxy?

Accepted Answer

A) The occurrence of supernovae in the spiral arms 
B) The flattened shape of the galaxy 
C) The shell of expanding gas 3 kpc from the center 
D) Thousands of pulsars in the center of the galaxy 
A) The occurrence of supernovae in the spiral arms 
B) The flattened shape of the galaxy 
C) The shell of expanding gas 3 kpc from the center 
D) Thousands of pulsars in the center of the galaxy

Question 18

The density wave theory for the formation of spiral arms predicts that

Accepted Answer

A) The arms will wrap up in the lifetime of the galaxy. 
B) The arms contain newborn stars triggered by the density waves 
C) The arms are caused mainly by tidal interactions 
D) Elliptical galaxies will eventually become barred spirals 
E) The arms have a high density of solar-type stars 
A) The arms will wrap up in the lifetime of the galaxy. 
B) The arms contain newborn stars triggered by the density waves 
C) The arms are caused mainly by tidal interactions 
D) Elliptical galaxies will eventually become barred spirals 
E) The arms have a high density of solar-type stars

Question 19

Consider a star that orbits the galaxy at half the Sun's distance.If that star has the same orbital period as the Sun,how does the mass interior to the star's orbit compare to the mass interior to the Sun's orbit?

Accepted Answer

A) The same 
B) One-eighth 
C) One-quarter 
D) One-half 
A) The same 
B) One-eighth 
C) One-quarter 
D) One-half

Question 20

Why are most O and B stars found in the arms of the galaxy?

Accepted Answer

A) They are magnetically bound to the spiral arms 
B) They ride on the crests of the density wave 
C) They are short-lived stars that form in spiral arms 
D) They have been ejected recently from the center of the galaxy 
A) They are magnetically bound to the spiral arms 
B) They ride on the crests of the density wave 
C) They are short-lived stars that form in spiral arms 
D) They have been ejected recently from the center of the galaxy

Exam 22: The Milky Way

The distance of the Sun from the galactic center is considered to be around what value?

We cannot see the other side of the galaxy primarily because our view is blocked by

Why are HII regions red in color?

Which of the following statements about the density wave model for spiral arms is FALSE?

What assumption about globular clusters did Harlow Shapley make in order to determine the location of and distance to the center of the Milky Way?

How do we know that the Milky Way has a spiral structure?

Which of the following best describes the way that our galaxy has changed throughout its history?

Our Milky Way Galaxy is considered to have how many main spiral arms?

Astronomers of about the year 1900 didn't know of the existence of interstellar dust.As a result they

The hydrogen in an HII region is

Which of the following statements describes the mass in the outer part of the Milky Way (beyond the orbit of the sun)?

Which of the following must be known in order to determine the amount of galactic mass that lies within the Sun's orbit?

The distance to the center of our galaxy can be found from

Which of the following is the best description of the rotation curve of the galaxy between the Sun's orbital distance and twice the Sun's orbital distance?

Which of the following is an example of population II?

The galaxy has become enriched in heavy elements since it formed.What is responsible for the enrichment?

Which of the following is evidence for violent activity at the center of the galaxy?

The density wave theory for the formation of spiral arms predicts that

Consider a star that orbits the galaxy at half the Sun's distance.If that star has the same orbital period as the Sun,how does the mass interior to the star's orbit compare to the mass interior to the Sun's orbit?

Why are most O and B stars found in the arms of the galaxy?

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