Question 1

All heavy elements are made during supernova explosions.

Accepted Answer

A) True 
 B)False

Question 2

How are interstellar bubbles made?

Accepted Answer

A) by the winds of massive stars and supernovae explosions 
B) by the collapse of a gas cloud to form stars 
C) by collisions between the Milky Way and satellite dwarf galaxies 
D) by the rapidly rotating magnetic fields of pulsars 
E) by the ejection of planetary nebulae from low- mass stars 
A) by the winds of massive stars and supernovae explosions 
B) by the collapse of a gas cloud to form stars 
C) by collisions between the Milky Way and satellite dwarf galaxies 
D) by the rapidly rotating magnetic fields of pulsars 
E) by the ejection of planetary nebulae from low- mass stars

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

Shapley used the distribution of globular clusters in our galaxy to determine that the Sun was not at the center of the Milky Way.

Accepted Answer

A) True 
 B)False

Question 5

How do disk stars orbit the center of the galaxy?

Accepted Answer

A) They have orbits randomly inclined and in different directions relative to the galactic center. 
B) They follow spiral paths along the spiral arms. 
C) They follow orbits that move up and down through the disk, typically taking them about 50,000 light- years above and below the disk on each orbit. 
D) They all orbit in roughly the same plane and in the same direction. 
A) They have orbits randomly inclined and in different directions relative to the galactic center. 
B) They follow spiral paths along the spiral arms. 
C) They follow orbits that move up and down through the disk, typically taking them about 50,000 light- years above and below the disk on each orbit. 
D) They all orbit in roughly the same plane and in the same direction.

Question 6

Where does most star formation occur in the Milky Way Galaxy?

Accepted Answer

A) in the spiral arms 
B) everywhere throughout the galactic disk 
C) within the halo 
D) in the central bulge 
A) in the spiral arms 
B) everywhere throughout the galactic disk 
C) within the halo 
D) in the central bulge

Question 7

Most of the mass of the Milky Way is located in the halo of the galaxy in the form of dark matter.

Accepted Answer

A) True 
 B)False

Question 8

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

Accepted Answer

A) It absorbs all wavelengths of light. 
B) It prevents us from seeing most of the galactic disk with visible and ultraviolet light. 
C) It produces so much visible light that it blocks our view of anything beyond it. 
D) It has no effect on visible- light observations, but prevents us from studying the galactic center with radio waves or X- rays. 
A) It absorbs all wavelengths of light. 
B) It prevents us from seeing most of the galactic disk with visible and ultraviolet light. 
C) It produces so much visible light that it blocks our view of anything beyond it. 
D) It has no effect on visible- light observations, but prevents us from studying the galactic center with radio waves or X- rays.

Question 9

If we could watch spiral arms from a telescope situated above the Milky Way over 500 million years, what would we see happen?

Accepted Answer

A) The spiral arms will eventually dissipate and fade away, since they are a temporary phenomenon that should only last for a million years or so. 
B) The spiral arms will eventually unwind, as centripetal forces send the stars flying outwards into intergalactic space. 
C) The spiral arms will seem to "wind up," to wrap more and more tightly around the center of the Galaxy. 
D) Stars will move through the spiral arms, bunching up closer as they pass through. Young hot stars will form and die within the arms before having a chance to move out. 
A) The spiral arms will eventually dissipate and fade away, since they are a temporary phenomenon that should only last for a million years or so. 
B) The spiral arms will eventually unwind, as centripetal forces send the stars flying outwards into intergalactic space. 
C) The spiral arms will seem to "wind up," to wrap more and more tightly around the center of the Galaxy. 
D) Stars will move through the spiral arms, bunching up closer as they pass through. Young hot stars will form and die within the arms before having a chance to move out.

Question 10

The average speed of stars relative to the Sun in the solar neighborhood is about 20 km/s. Suppose you discover a star in the solar neighborhood that is moving relative to the Sun at a much higher speed, say 220 km/s. What kind of orbit does this star probably have around the Milky Way? In what part of the galaxy does it spend most of its time? Explain.

Accepted Answer

Since stars that are traveling along wit

Question 11

Suppose you read somewhere that 10 percent of the matter in the Milky Way is in the form of dust grains. Should you be surprised? If so, why?

Accepted Answer

A) Given how easily dust grains can form, 10 percent is a surprisingly low fraction. 
B) There is nothing surprising about the 10 percent figure because dust grains are the material from which stars are born. 
C) The fraction of 10 percent is surprisingly high because dust grains can form only at low temperatures. 
D) The fraction of 10 percent cannot be correct. Dust grains are solid and only 2 percent of the matter in the galaxy is made of anything besides hydrogen and helium. 
A) Given how easily dust grains can form, 10 percent is a surprisingly low fraction. 
B) There is nothing surprising about the 10 percent figure because dust grains are the material from which stars are born. 
C) The fraction of 10 percent is surprisingly high because dust grains can form only at low temperatures. 
D) The fraction of 10 percent cannot be correct. Dust grains are solid and only 2 percent of the matter in the galaxy is made of anything besides hydrogen and helium.

Question 12

What produces the 21- cm radio line that we can be used to map the Milky Way Galaxy?

Accepted Answer

A) molecular hydrogen 
B) ionized hydrogen 
C) carbon monoxide 
D) atomic hydrogen 
E) helium 
A) molecular hydrogen 
B) ionized hydrogen 
C) carbon monoxide 
D) atomic hydrogen 
E) helium

Question 13

Based on observations, which of the following statements about stars in the Milky Way is generally true?

Accepted Answer

A) The older the star, the bluer its color. 
B) The younger the star, the higher its mass. 
C) The older the star, the faster its orbital speed. 
D) The older the star, the lower its abundance of heavy elements. 
E) The less massive the star, the older it is. 
A) The older the star, the bluer its color. 
B) The younger the star, the higher its mass. 
C) The older the star, the faster its orbital speed. 
D) The older the star, the lower its abundance of heavy elements. 
E) The less massive the star, the older it is.

Question 14

Which of the following patterns in the Milky Way structure is consistent with the idea that the Milky Way has not suffered a major collision with another massive galaxy?

Accepted Answer

A) The disk is composed of stars orbiting in the same plane, same direction. 
B) Globular clusters are compact groups of thousands of stars. 
C) The disk is composed of stars of many different ages. 
D) The halo is full of old stars orbiting in many different directions. 
A) The disk is composed of stars orbiting in the same plane, same direction. 
B) Globular clusters are compact groups of thousands of stars. 
C) The disk is composed of stars of many different ages. 
D) The halo is full of old stars orbiting in many different directions.

Question 15

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

Accepted Answer

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

Question 16

How do we know the total mass of the Milky Way Galaxy that is contained within the Sun's orbital path?

Accepted Answer

A) by applying Newton's version of Kepler's third law (or the equivalent orbital velocity law)to the Sun's orbit around the center of the Galaxy 
B) by counting the number of stars visible in this region of the galaxy 
C) by using the law of conservation of angular momentum to calculate the orbital speeds of nearby stars 
D) by estimating the amount of gas and dust in between the stars 
A) by applying Newton's version of Kepler's third law (or the equivalent orbital velocity law)to the Sun's orbit around the center of the Galaxy 
B) by counting the number of stars visible in this region of the galaxy 
C) by using the law of conservation of angular momentum to calculate the orbital speeds of nearby stars 
D) by estimating the amount of gas and dust in between the stars

Question 17

Fill in the blank: Elements heavier than hydrogen and helium constitute about of the mass of the interstellar medium.

Accepted Answer

A) 2% 
B) 0)002% 
C) 98% 
D) 70% 
A) 2% 
B) 0)002% 
C) 98% 
D) 70%

Question 18

Which of the following stars would be most likely to have the same abundance of elements heavier than helium as a red main sequence star in globular cluster M13?

Accepted Answer

A) red giant in globular cluster M13 
B) a red main- sequence star in the disk of the Milky Way 
C) None of these choices 
A) red giant in globular cluster M13 
B) a red main- sequence star in the disk of the Milky Way 
C) None of these choices

Question 19

Why are we unlikely to find Earth- like planets around halo stars in the Galaxy?

Accepted Answer

A) Halo stars formed from gas containing few heavy elements, the elements needed to create terrestrial planets like the Earth. 
B) Halo stars formed directly from gas in the halo without forming a planetary disk. 
C) Halo stars formed from gas containing lots of heavy elements and few of the light elements needed to create terrestrial planets like the Earth. 
D) Planets around stars are extremely rare in our Galaxy. 
E) Halo stars are all very low mass stars that cannot hold onto planets. 
A) Halo stars formed from gas containing few heavy elements, the elements needed to create terrestrial planets like the Earth. 
B) Halo stars formed directly from gas in the halo without forming a planetary disk. 
C) Halo stars formed from gas containing lots of heavy elements and few of the light elements needed to create terrestrial planets like the Earth. 
D) Planets around stars are extremely rare in our Galaxy. 
E) Halo stars are all very low mass stars that cannot hold onto planets.

Question 20

What kind of object do we think lies in the center of the Milky Way Galaxy?

Accepted Answer

A) a dense cluster of young, hot stars 
B) a gigantic X- ray binary system 
C) an enormous collection of dark matter, explaining why we detect no light at all from the galactic center 
D) a 3 to 4 million solar mass black hole 
A) a dense cluster of young, hot stars 
B) a gigantic X- ray binary system 
C) an enormous collection of dark matter, explaining why we detect no light at all from the galactic center 
D) a 3 to 4 million solar mass black hole

All heavy elements are made during supernova explosions.

How are interstellar bubbles made?

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.

Shapley used the distribution of globular clusters in our galaxy to determine that the Sun was not at the center of the Milky Way.

How do disk stars orbit the center of the galaxy?

Where does most star formation occur in the Milky Way Galaxy?

Most of the mass of the Milky Way is located in the halo of the galaxy in the form of dark matter.

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

If we could watch spiral arms from a telescope situated above the Milky Way over 500 million years, what would we see happen?

Suppose you read somewhere that 10 percent of the matter in the Milky Way is in the form of dust grains. Should you be surprised? If so, why?

What produces the 21- cm radio line that we can be used to map the Milky Way Galaxy?

Based on observations, which of the following statements about stars in the Milky Way is generally true?

Which of the following patterns in the Milky Way structure is consistent with the idea that the Milky Way has not suffered a major collision with another massive galaxy?

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

How do we know the total mass of the Milky Way Galaxy that is contained within the Sun's orbital path?

Fill in the blank: Elements heavier than hydrogen and helium constitute about of the mass of the interstellar medium.

Which of the following stars would be most likely to have the same abundance of elements heavier than helium as a red main sequence star in globular cluster M13?

Why are we unlikely to find Earth- like planets around halo stars in the Galaxy?

What kind of object do we think lies in the center of the Milky Way Galaxy?

A Modern View of 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 the Solar System

Earth and the Terrestrial Worlds

Jovian Planet System

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

Other Planetary Systems: the New Science of Distant Worlds

Our Star

Surveying the Stars

Star Stuff

The Bizarre Stellar Graveyard

A Universe of Galaxies

The Birth of the Universe

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

Life in the Universe

Filters

Exam 15: Our Galaxy

All heavy elements are made during supernova explosions.

How are interstellar bubbles made?

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.

Shapley used the distribution of globular clusters in our galaxy to determine that the Sun was not at the center of the Milky Way.

How do disk stars orbit the center of the galaxy?

Where does most star formation occur in the Milky Way Galaxy?

Most of the mass of the Milky Way is located in the halo of the galaxy in the form of dark matter.

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

If we could watch spiral arms from a telescope situated above the Milky Way over 500 million years, what would we see happen?

Suppose you read somewhere that 10 percent of the matter in the Milky Way is in the form of dust grains. Should you be surprised? If so, why?

What produces the 21- cm radio line that we can be used to map the Milky Way Galaxy?

Based on observations, which of the following statements about stars in the Milky Way is generally true?

Which of the following patterns in the Milky Way structure is consistent with the idea that the Milky Way has not suffered a major collision with another massive galaxy?

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

How do we know the total mass of the Milky Way Galaxy that is contained within the Sun's orbital path?

Fill in the blank: Elements heavier than hydrogen and helium constitute about of the mass of the interstellar medium.

Which of the following stars would be most likely to have the same abundance of elements heavier than helium as a red main sequence star in globular cluster M13?

Why are we unlikely to find Earth- like planets around halo stars in the Galaxy?

What kind of object do we think lies in the center of the Milky Way Galaxy?

A Modern View of 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 the Solar System

Earth and the Terrestrial Worlds

Jovian Planet System

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

Other Planetary Systems: the New Science of Distant Worlds

Our Star

Surveying the Stars

Star Stuff

The Bizarre Stellar Graveyard

A Universe of Galaxies

The Birth of the Universe

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

Life in the Universe

Filters