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Chapter 19 Reading Quiz Clickers
The Cosmic Perspective
Seventh Edition
Our Galaxy
© 2014 Pearson Education, Inc.
Chapter 19
19.1 The Milky Way Revealed
• 
• 
What does our galaxy look like?
How do stars orbit in our galaxy?
© 2014 Pearson Education, Inc.
Chapter 19
Where are globular clusters located in the Milky
Way?
a) 
b) 
c) 
d) 
disk
central bulge
halo
spiral arms
© 2014 Pearson Education, Inc.
Chapter 19
Where are globular clusters located in the Milky
Way?
a) 
b) 
c) 
d) 
disk
central bulge
halo
spiral arms
© 2014 Pearson Education, Inc.
Chapter 19
Where is the Sun located in the Milky Way?
a) 
b) 
c) 
d) 
e) 
about 27,000 light-years from the center, in the disk
about 27,000 light-years from the center, in the halo
about 100,000 light-years from the center, in the disk
about 8000 light-years from the center, in the disk
about 1000 light-years from the center, in the halo
© 2014 Pearson Education, Inc.
Chapter 19
Where is the Sun located in the Milky Way?
a) 
b) 
c) 
d) 
e) 
about 27,000 light-years from the center, in the disk
about 27,000 light-years from the center, in the halo
about 100,000 light-years from the center, in the disk
about 8000 light-years from the center, in the disk
about 1000 light-years from the center, in the halo
© 2014 Pearson Education, Inc.
Chapter 19
How thick is the disk of the Milky Way?
a) 
b) 
c) 
d) 
e) 
100 light-years
1000 light-years
5000 light-years
20,000 light-years
35,000 light-years
© 2014 Pearson Education, Inc.
Chapter 19
How thick is the disk of the Milky Way?
a) 
b) 
c) 
d) 
e) 
100 light-years
1000 light-years
5000 light-years
20,000 light-years
35,000 light-years
© 2014 Pearson Education, Inc.
Chapter 19
How long does it take the Sun to complete one
orbit of the Milky Way?
a) 
b) 
c) 
d) 
100,000 years
12 million years
230 million years
1.2 billion years
© 2014 Pearson Education, Inc.
Chapter 19
How long does it take the Sun to complete one
orbit of the Milky Way?
a) 
b) 
c) 
d) 
100,000 years
12 million years
230 million years
1.2 billion years
© 2014 Pearson Education, Inc.
Chapter 19
19.2 Galactic Recycling
• 
• 
How is gas recycled in our galaxy?
Where do stars tend to form in our galaxy?
© 2014 Pearson Education, Inc.
Chapter 19
What produces the 21-centimeter emission
line?
a) 
b) 
c) 
d) 
e) 
supernova remnants
atomic hydrogen gas
planetary nebulae
CO in giant molecular clouds
super bubble emissions
© 2014 Pearson Education, Inc.
Chapter 19
What produces the 21-centimeter emission
line?
a) 
b) 
c) 
d) 
e) 
supernova remnants
atomic hydrogen gas
planetary nebulae
CO in giant molecular clouds
super bubble emissions
© 2014 Pearson Education, Inc.
Chapter 19
What creates hot bubbles in the Milky Way?
a)  radiation from the supermassive black hole at the
galactic center
b)  radiation from dense globular clusters in the
galactic halo
c)  radiation from supernova explosions
d)  radiation from black hole accretion disks
e)  all of the above
© 2014 Pearson Education, Inc.
Chapter 19
What creates hot bubbles in the Milky Way?
a)  radiation from the supermassive black hole at the
galactic center
b)  radiation from dense globular clusters in the
galactic halo
c)  radiation from supernova explosions
d)  radiation from black hole accretion disks
e)  all of the above
© 2014 Pearson Education, Inc.
Chapter 19
What is the star-gas-star cycle?
a)  the recycling of stellar material from stars into the interstellar
medium which then forms new stars
b)  the transfer of material from one star through an accretion
disk to another star in a binary star system
c)  the shockwave from a supernova triggering gas clouds to
condense into new stars
d)  the transfer of gas from stars in one part of the galaxy
through the halo to other parts of the galaxy via galactic
fountains
© 2014 Pearson Education, Inc.
Chapter 19
What is the star-gas-star cycle?
a)  the recycling of stellar material from stars into the
interstellar medium which then forms new stars
b)  the transfer of material from one star through an accretion
disk to another star in a binary star system
c)  the shockwave from a supernova triggering gas clouds to
condense into new stars
d)  the transfer of gas from stars in one part of the galaxy
through the halo to other parts of the galaxy via galactic
fountains
© 2014 Pearson Education, Inc.
Chapter 19
Which of the following regions of interstellar
gas have the lowest temperatures?
a) 
b) 
c) 
d) 
e) 
hot bubbles
warm atomic gas
cool atomic clouds
molecular clouds
molecular cloud cores
© 2014 Pearson Education, Inc.
Chapter 19
Which of the following regions of interstellar
gas have the lowest temperatures?
a) 
b) 
c) 
d) 
e) 
hot bubbles
warm atomic gas
cool atomic clouds
molecular clouds
molecular cloud cores
© 2014 Pearson Education, Inc.
Chapter 19
Which of the following regions of interstellar
gas have the lowest densities?
a) 
b) 
c) 
d) 
e) 
hot bubbles
warm atomic gas
cool atomic clouds
molecular clouds
molecular cloud cores
© 2014 Pearson Education, Inc.
Chapter 19
Which of the following regions of interstellar
gas have the lowest densities?
a) 
b) 
c) 
d) 
e) 
hot bubbles
warm atomic gas
cool atomic clouds
molecular clouds
molecular cloud cores
© 2014 Pearson Education, Inc.
Chapter 19
In what part of the spectrum are hot gas
bubbles visible?
a) 
b) 
c) 
d) 
e) 
21-centimeter emission (radio)
near-infrared
gamma-rays
ultraviolet
X-rays
© 2014 Pearson Education, Inc.
Chapter 19
In what part of the spectrum are hot gas
bubbles visible?
a) 
b) 
c) 
d) 
e) 
21-centimeter emission (radio)
near-infrared
gamma-rays
ultraviolet
X-rays
© 2014 Pearson Education, Inc.
Chapter 19
What gives reflection nebulae their blue color?
a)  the blue light from nearby hot stars
b)  preferential scattering of blue light from dust grains
c)  emission lines in the blue part of the spectrum from
atomic hydrogen
d)  emission lines in the blue part of the spectrum from
molecular hydrogen
© 2014 Pearson Education, Inc.
Chapter 19
What gives reflection nebulae their blue color?
a)  the blue light from nearby hot stars
b)  preferential scattering of blue light from dust
grains
c)  emission lines in the blue part of the spectrum from
atomic hydrogen
d)  emission lines in the blue part of the spectrum from
molecular hydrogen
© 2014 Pearson Education, Inc.
Chapter 19
Where are most star-forming regions in the
Milky Way?
a) 
b) 
c) 
d) 
e) 
the central bulge
the halo
the spiral arms
the regions between the spiral arms
Star formation happens at roughly the same rate in
all regions of the Milky Way.
© 2014 Pearson Education, Inc.
Chapter 19
Where are most star-forming regions in the
Milky Way?
a) 
b) 
c) 
d) 
e) 
the central bulge
the halo
the spiral arms
the regions between the spiral arms
Star formation happens at roughly the same rate in
all regions of the Milky Way.
© 2014 Pearson Education, Inc.
Chapter 19
19.3 The History of the Milky Way
• 
• 
What clues to our galaxy's history do halo stars
hold?
How did our galaxy form?
© 2014 Pearson Education, Inc.
Chapter 19
Which of the following is not a difference
between the disk population and the spheroidal
population?
a)  The disk population contains younger stars than the
spheroidal population.
b)  The spheroidal population stars are low-mass stars.
c)  The spheroidal population stars have much lower fractions of
heavy elements than the disk population stars.
d)  Disk population stars are predominantly in clusters while the
spheroidal population are primarily alone or in binary
systems.
e)  none of the above (all are true)
© 2014 Pearson Education, Inc.
Chapter 19
Which of the following is not a difference
between the disk population and the spheroidal
population?
a)  The disk population contains younger stars than the
spheroidal population.
b)  The spheroidal population stars are low-mass stars.
c)  The spheroidal population stars have much lower fractions of
heavy elements than the disk population stars.
d)  Disk population stars are predominantly in clusters while
the spheroidal population are primarily alone or in
binary systems.
e)  none of the above (all are true)
© 2014 Pearson Education, Inc.
Chapter 19
Where did the oldest stars in the Milky Way
form?
a) 
b) 
c) 
d) 
in the protogalactic cloud
in the central bulge
in spiral arms
in the disk, but not in the spiral arms
© 2014 Pearson Education, Inc.
Chapter 19
Where did the oldest stars in the Milky Way
form?
a) 
b) 
c) 
d) 
in the protogalactic cloud
in the central bulge
in spiral arms
in the disk, but not in the spiral arms
© 2014 Pearson Education, Inc.
Chapter 19
How many dwarf galaxies are in the vicinity of
the Milky Way?
a) 
b) 
c) 
d) 
e) 
0
1
2
3
4
© 2014 Pearson Education, Inc.
Chapter 19
How many dwarf galaxies are in the vicinity of
the Milky Way?
a) 
b) 
c) 
d) 
e) 
0
1
2
3
4
© 2014 Pearson Education, Inc.
Chapter 19
19.4 The Mysterious Galactic Center
• 
What lies in the center of our galaxy?
© 2014 Pearson Education, Inc.
Chapter 19
What is the mass of the object at the center of
the Milky Way?
a) 
b) 
c) 
d) 
e) 
40,000 solar masses
300,000 solar masses
3 million solar masses
40 million solar masses
300 million solar masses
© 2014 Pearson Education, Inc.
Chapter 19
What is the mass of the object at the center of
the Milky Way?
a) 
b) 
c) 
d) 
e) 
40,000 solar masses
300,000 solar masses
3 million solar masses
40 million solar masses
300 million solar masses
© 2014 Pearson Education, Inc.