Question 1

How can we see through the interstellar medium?

Accepted Answer

A) by observing with telescopes above the Earth's atmosphere, such as the Hubble Space Telescope 
B) by observing at wavelengths (high- energy X- rays and long wavelength radio waves)that are not absorbed by interstellar dust 
C) by observing with only the biggest telescopes 
D) by observing only the brightest stars in the galaxy 
E) We cannot see through the interstellar medium. 
A) by observing with telescopes above the Earth's atmosphere, such as the Hubble Space Telescope 
B) by observing at wavelengths (high- energy X- rays and long wavelength radio waves)that are not absorbed by interstellar dust 
C) by observing with only the biggest telescopes 
D) by observing only the brightest stars in the galaxy 
E) We cannot see through the interstellar medium.

Question 2

Which of the following statements is not true of the object known as Sgr A* in the center of our Galaxy?

Accepted Answer

A) It is by far the brightest source of visible light lying in the direction of the galactic center. 
B) It is a source of X- ray emission that we have observed with telescopes in space. 
C) It is a source of bright radio emission. 
D) It is thought to harbor a black hole of more than 3 million solar masses. 
A) It is by far the brightest source of visible light lying in the direction of the galactic center. 
B) It is a source of X- ray emission that we have observed with telescopes in space. 
C) It is a source of bright radio emission. 
D) It is thought to harbor a black hole of more than 3 million solar masses.

Question 3

Observational Bias: The history of human understanding of the structure of the Milky Way starts with the bias that humans use visible light to see. Imagine you were a creature on another planet in the disk of the Milky Way who used radio waves to "see" the universe. What would have been your starting point for the structure of the Milky Way? What components would you have found easier to detect? What components would have been harder?

Accepted Answer

As a creature on another planet in the d

Question 4

What do we mean by the star- gas- star cycle?

Accepted Answer

A) It is the idea that stars in close binary systems can exchange gas with one another. 
B) It is the continuous recycling of gas in the galactic disk between stars and the interstellar medium. 
C) It describes the orbits of the stars and interstellar medium around the center of the galaxy. 
D) It is the set of nuclear reactions by which heavy elements are produced in the cores of massive stars. 
A) It is the idea that stars in close binary systems can exchange gas with one another. 
B) It is the continuous recycling of gas in the galactic disk between stars and the interstellar medium. 
C) It describes the orbits of the stars and interstellar medium around the center of the galaxy. 
D) It is the set of nuclear reactions by which heavy elements are produced in the cores of massive stars.

Question 5

The star- gas- star cycle will continue forever because stars are continually recycling gas. 110)

Accepted Answer

A) True 
 B)False

Question 6

What do we call the bright, sphere- shaped region of stars that occupies the central few thousand light- years of the Milky Way Galaxy?

Accepted Answer

A) a globular cluster 
B) the galaxy's halo 
C) the galaxy's disk 
D) the galaxy's bulge 
A) a globular cluster 
B) the galaxy's halo 
C) the galaxy's disk 
D) the galaxy's bulge

Question 7

What evidence suggests that the protogalactic cloud that formed the Milky Way resulted from several collisions among smaller clouds?

Accepted Answer

A) The Milky Way is the central galaxy of a dense cluster of galaxies. 
B) Halo stars differ in age and heavy- element content, but these variations do not seem to depend on the stars' distance from the galactic center. 
C) The stars in the halo of the Milky Way are organized into several dense clusters arranged throughout the halo. 
D) The Milky Way resembles an elliptical galaxy more than other spirals do. 
E) The bulge of the Milky Way is surrounded by many globular clusters, just as elliptical galaxies are. 
A) The Milky Way is the central galaxy of a dense cluster of galaxies. 
B) Halo stars differ in age and heavy- element content, but these variations do not seem to depend on the stars' distance from the galactic center. 
C) The stars in the halo of the Milky Way are organized into several dense clusters arranged throughout the halo. 
D) The Milky Way resembles an elliptical galaxy more than other spirals do. 
E) The bulge of the Milky Way is surrounded by many globular clusters, just as elliptical galaxies are.

Question 8

Approximately how far is the Sun from the center of the galaxy?

Accepted Answer

A) 2,700 light- years 
B) 27,000 light- years 
C) 27 million light- years 
D) 270 light- years 
E) 27 light- years 
A) 2,700 light- years 
B) 27,000 light- years 
C) 27 million light- years 
D) 270 light- years 
E) 27 light- years

Question 9

Compared with stars in the disk, orbits of stars in the halo

Accepted Answer

A) do not have to be around the galactic center. 
B) are confined to a relatively thin plane. 
C) are elliptical, orbiting in the same direction. 
D) are elliptical, with random orientations. 
E) do not have to pass through the plane of the galaxy. 
A) do not have to be around the galactic center. 
B) are confined to a relatively thin plane. 
C) are elliptical, orbiting in the same direction. 
D) are elliptical, with random orientations. 
E) do not have to pass through the plane of the galaxy.

Question 10

Sound waves in the interstellar medium

Accepted Answer

A) travel so slowly that they are undetectable. 
B) can travel through the gas, but the very low density of the interstellar medium makes them inaudible. 
C) can travel through the halo interstellar medium but not the disk of the galaxy. 
D) cannot travel through the gas. 
E) travel extremely quickly and are therefore very loud. 
A) travel so slowly that they are undetectable. 
B) can travel through the gas, but the very low density of the interstellar medium makes them inaudible. 
C) can travel through the halo interstellar medium but not the disk of the galaxy. 
D) cannot travel through the gas. 
E) travel extremely quickly and are therefore very loud.

Question 11

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) No model can explain the existence of the arms, which rotate with the galaxy like the fins of a giant pinwheel toy. 
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) The spiral arms are composed of groups of stars that are bound together by gravity and therefore always stay together as the galaxy rotates. 
A) The spiral arms are a wave of star formation caused by wave of density propagating outward through the disk of the galaxy. 
B) No model can explain the existence of the arms, which rotate with the galaxy like the fins of a giant pinwheel toy. 
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) The spiral arms are composed of groups of stars that are bound together by gravity and therefore always stay together as the galaxy rotates.

Question 12

The most common form of gas in the disk of the Milky Way galaxy is .

Accepted Answer

A) molecular hydrogen 
B) gas in stellar winds 
C) atomic hydrogen gas 
D) gas in hot bubbles 
A) molecular hydrogen 
B) gas in stellar winds 
C) atomic hydrogen gas 
D) gas in hot bubbles

Question 13

Briefly describe the star- gas- star cycle.

Accepted Answer

During a star's lifetime, it fuses hydro

Question 14

How do high mass stars transport newly formed elements into the interstellar medium?

Accepted Answer

A) supernova explosions 
B) stellar winds 
C) formation of planetary nebula 
D) A and B 
E) A and C 
A) supernova explosions 
B) stellar winds 
C) formation of planetary nebula 
D) A and B 
E) A and C

Question 15

Spiral arms appear bright because .

Accepted Answer

A) they contain more hot young stars than other parts of the disk 
B) they are the only places where we find stars within the disk of the galaxy 
C) they contain more molecular clouds than other parts of the disk 
D) they contain far more stars than other parts of the galactic disk 
A) they contain more hot young stars than other parts of the disk 
B) they are the only places where we find stars within the disk of the galaxy 
C) they contain more molecular clouds than other parts of the disk 
D) they contain far more stars than other parts of the galactic disk

Question 16

Interstellar dust consists mostly of .

Accepted Answer

A) microscopic particles of carbon and silicon 
B) ozone "smog" 
C) hydrogen and helium atoms 
D) the same tiny particles found in household dust 
E) tiny grains of water ice 
A) microscopic particles of carbon and silicon 
B) ozone "smog" 
C) hydrogen and helium atoms 
D) the same tiny particles found in household dust 
E) tiny grains of water ice

Question 17

The Sun is located near the edge of our galaxy, approximately 100,000 light- years from the galactic center.

Accepted Answer

A) True 
 B)False

Question 18

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

Accepted Answer

A) True 
 B)False

Question 19

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 20

Almost all elements heavier than hydrogen and helium were made inside stars.

Accepted Answer

A) True 
 B)False

How can we see through the interstellar medium?

Which of the following statements is not true of the object known as Sgr A* in the center of our Galaxy?

What do we mean by the star- gas- star cycle?

The star- gas- star cycle will continue forever because stars are continually recycling gas. 110)

What do we call the bright, sphere- shaped region of stars that occupies the central few thousand light- years of the Milky Way Galaxy?

What evidence suggests that the protogalactic cloud that formed the Milky Way resulted from several collisions among smaller clouds?

Approximately how far is the Sun from the center of the galaxy?

Compared with stars in the disk, orbits of stars in the halo

Sound waves in the interstellar medium

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

The most common form of gas in the disk of the Milky Way galaxy is .

Briefly describe the star- gas- star cycle.

How do high mass stars transport newly formed elements into the interstellar medium?

Spiral arms appear bright because .

Interstellar dust consists mostly of .

The Sun is located near the edge of our galaxy, approximately 100,000 light- years from the galactic center.

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

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

Almost all elements heavier than hydrogen and helium were made inside stars.

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

How can we see through the interstellar medium?

Which of the following statements is not true of the object known as Sgr A* in the center of our Galaxy?

What do we mean by the star- gas- star cycle?

The star- gas- star cycle will continue forever because stars are continually recycling gas. 110)

What do we call the bright, sphere- shaped region of stars that occupies the central few thousand light- years of the Milky Way Galaxy?

What evidence suggests that the protogalactic cloud that formed the Milky Way resulted from several collisions among smaller clouds?

Approximately how far is the Sun from the center of the galaxy?

Compared with stars in the disk, orbits of stars in the halo

Sound waves in the interstellar medium

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

The most common form of gas in the disk of the Milky Way galaxy is .

Briefly describe the star- gas- star cycle.

How do high mass stars transport newly formed elements into the interstellar medium?

Spiral arms appear bright because .

Interstellar dust consists mostly of .

The Sun is located near the edge of our galaxy, approximately 100,000 light- years from the galactic center.

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

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

Almost all elements heavier than hydrogen and helium were made inside stars.

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