Question 1

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

Accepted Answer

A) True 
 B)False  False

Question 2

Which constellation lies in the direction toward the galactic center?

Accepted Answer

A) Orion 
B) the Big Dipper 
C) Leo 
D) Sagittarius 
E) Taurus 
A) Orion 
B) the Big Dipper 
C) Leo 
D) Sagittarius 
E) Taurus D

Question 3

What evidence suggests that we live inside a hot local bubble?

Accepted Answer

X-ray telescopes in space reveal that we are surrounded by hot,X-ray-emitting gas coming from nearby in every direction.Surrounding this hot gas lies a region of much cooler gas.This suggests that a number of supernovae have detonated within our stellar neighborhood over the last several million years and that we and all our stellar neighbors live inside a hot bubble.

Question 4

What is the best evidence for an extremely massive black hole in the center of the Milky Way?

Accepted Answer

A) Huge amounts of X-rays are pouring out of the center of the galaxy. 
B) The center of our galaxy hosts a pulsar that is spinning so fast that it could only be a black hole. 
C) We observe stars vanishing in the center of the Galaxy as they are sucked into the black hole. 
D) The orbits of stars in the center of the galaxy indicate that the presence of 3- to 4-million-solar-mass object in a region no larger than our Solar System. 
A) Huge amounts of X-rays are pouring out of the center of the galaxy. 
B) The center of our galaxy hosts a pulsar that is spinning so fast that it could only be a black hole. 
C) We observe stars vanishing in the center of the Galaxy as they are sucked into the black hole. 
D) The orbits of stars in the center of the galaxy indicate that the presence of 3- to 4-million-solar-mass object in a region no larger than our Solar System.

Question 5

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

Question 6

The image of our galaxy in radio emission from CO,mapping the distribution of molecular clouds,is closest to the image of our galaxy in

Accepted Answer

A) 21-cm-line radio emission from atomic hydrogen. 
B) visible light,showing the edges of supernova bubbles. 
C) visible light,which is closest to how the night sky appears from Earth. 
D) X-rays from hot gas bubbles in the disk. 
E) infrared emission from interstellar dust grains. 
A) 21-cm-line radio emission from atomic hydrogen. 
B) visible light,showing the edges of supernova bubbles. 
C) visible light,which is closest to how the night sky appears from Earth. 
D) X-rays from hot gas bubbles in the disk. 
E) infrared emission from interstellar dust grains.

Question 7

Which of the following statements about halo stars is false?

Accepted Answer

A) Halo stars have random orbits about the Milky Way center. 
B) Halo stars are no longer being formed at the current epoch. 
C) All halo stars are less massive than our Sun. 
D) Halo stars are made entirely of hydrogen and helium with no heavy elements. 
E) Halo stars are some of the oldest known objects in the universe. 
A) Halo stars have random orbits about the Milky Way center. 
B) Halo stars are no longer being formed at the current epoch. 
C) All halo stars are less massive than our Sun. 
D) Halo stars are made entirely of hydrogen and helium with no heavy elements. 
E) Halo stars are some of the oldest known objects in the universe.

Question 8

We can see most of the galaxy with visible light.

Accepted Answer

A) True 
 B)False

Question 9

What is the galactic fountain model?

Accepted Answer

A) the idea that there is a lot of interstellar water vapor 
B) the theory that the Milky Way is a spiral galaxy and looks like a whirlpool from above 
C) the theory that hot,ionized gas blows out of the galactic center like a jet or fountain 
D) the theory that hot,ionized gas blown out of the galactic disk and into the halo by superbubbles cools down and falls back into the disk 
E) none of the above 
A) the idea that there is a lot of interstellar water vapor 
B) the theory that the Milky Way is a spiral galaxy and looks like a whirlpool from above 
C) the theory that hot,ionized gas blows out of the galactic center like a jet or fountain 
D) the theory that hot,ionized gas blown out of the galactic disk and into the halo by superbubbles cools down and falls back into the disk 
E) none of the above

Question 10

How are interstellar bubbles made?

Accepted Answer

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

Question 11

Process of Science: Explain how observations of other galaxies can help us understand our own.

Accepted Answer

We can see other galaxies from an outsid

Question 12

What do we mean by the interstellar medium?

Accepted Answer

A) the dust that fills the halo of the Milky Way Galaxy 
B) the middle section of the Milky Way Galaxy 
C) the gas and dust that lies in between the stars in the Milky Way Galaxy 
D) the name of an oracle who can channel messages from beings that live near the star called Vega 
A) the dust that fills the halo of the Milky Way Galaxy 
B) the middle section of the Milky Way Galaxy 
C) the gas and dust that lies in between the stars in the Milky Way Galaxy 
D) the name of an oracle who can channel messages from beings that live near the star called Vega

Question 13

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

Accepted Answer

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

Question 14

What evidence supports the galactic fountain model?

Accepted Answer

A) We see a jet of ionized gas shooting out of the bulge of our galaxy. 
B) We have mapped several spiral arms of the Milky Way Galaxy. 
C) We see hot gas above the disk of the galaxy and cool gas that appears to be raining down from the halo. 
D) We have observed a lot of water molecules in the interstellar medium. 
E) We have no evidence yet for the galactic fountain model. 
A) We see a jet of ionized gas shooting out of the bulge of our galaxy. 
B) We have mapped several spiral arms of the Milky Way Galaxy. 
C) We see hot gas above the disk of the galaxy and cool gas that appears to be raining down from the halo. 
D) We have observed a lot of water molecules in the interstellar medium. 
E) We have no evidence yet for the galactic fountain model.

Question 15

Where are most heavy elements made?

Accepted Answer

A) in the interstellar medium 
B) in stars and supernovae 
C) in the Big Bang,when the universe first began 
D) none of the above 
E) all of the above 
A) in the interstellar medium 
B) in stars and supernovae 
C) in the Big Bang,when the universe first began 
D) none of the above 
E) all of the above

Question 16

What do halo stars do differently from disk stars?

Accepted Answer

A) They remain stationary,quite unlike disk stars that orbit the galactic center. 
B) They orbit the galactic center with many different inclinations,while disk stars all orbit in nearly the same plane. 
C) Halo stars explode as supernovae much more frequently than disk stars. 
D) They orbit the center of the galaxy at much lower speeds than disk star. 
A) They remain stationary,quite unlike disk stars that orbit the galactic center. 
B) They orbit the galactic center with many different inclinations,while disk stars all orbit in nearly the same plane. 
C) Halo stars explode as supernovae much more frequently than disk stars. 
D) They orbit the center of the galaxy at much lower speeds than disk star.

Question 17

What produces the striking red,blue,and black colors of ionization nebulae?

Accepted Answer

The bright red color is produced by an e

Question 18

Which of the following does not accurately describe what we observe toward the Galactic center?

Accepted Answer

A) at radio wavelengths,we see giant gas clouds threaded by powerful magnetic fields 
B) at infrared wavelengths,we see a massive stellar cluster 
C) at optical wavelengths,we see a cluster of old,red stars 
D) at X-rays,we see faint emission from an accretion disk around a black hole 
A) at radio wavelengths,we see giant gas clouds threaded by powerful magnetic fields 
B) at infrared wavelengths,we see a massive stellar cluster 
C) at optical wavelengths,we see a cluster of old,red stars 
D) at X-rays,we see faint emission from an accretion disk around a black hole

Question 19

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

Question 20

How do disk stars orbit the center of the galaxy?

Accepted Answer

A) They all orbit in roughly the same plane and in the same direction. 
B) They have orbits randomly inclined and in different directions relative to the galactic center. 
C) They follow spiral paths along the spiral arms. 
D) 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. 
A) They all orbit in roughly the same plane and in the same direction. 
B) They have orbits randomly inclined and in different directions relative to the galactic center. 
C) They follow spiral paths along the spiral arms. 
D) 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.

Exam 19: Our Galaxy

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

Which constellation lies in the direction toward the galactic center?

What evidence suggests that we live inside a hot local bubble?

What is the best evidence for an extremely massive black hole in the center of the Milky Way?

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

The image of our galaxy in radio emission from CO,mapping the distribution of molecular clouds,is closest to the image of our galaxy in

Which of the following statements about halo stars is false?

We can see most of the galaxy with visible light.

What is the galactic fountain model?

How are interstellar bubbles made?

Process of Science: Explain how observations of other galaxies can help us understand our own.

What do we mean by the interstellar medium?

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

What evidence supports the galactic fountain model?

Where are most heavy elements made?

What do halo stars do differently from disk stars?

What produces the striking red,blue,and black colors of ionization nebulae?

Which of the following does not accurately describe what we observe toward the Galactic center?

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

How do disk stars orbit the center of the 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 and Matter: Reading Messages from the Cosmos

Telescopes: Portals of Discovery

Our Planetary System

Formation of the Solar System

Planetary Geology: Earth and the Other Terrestrial Worlds

Planetary Atmospheres: Earth and the Other Terrestrial Worlds

Jovian Planet Systems

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 Birth

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The Bizarre Stellar Graveyard

Galaxies and the Foundations of Modern Cosmology

Galaxy Evolution

The Birth of the Universe

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

Life in the Universe

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