Question 1

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

Accepted Answer

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

Question 2

What elements do astronomers consider heavy elements?

Accepted Answer

A)  elements that are heavier than iron 
B)  elements that are heavier than carbon 
C)  elements that are heavier than hydrogen 
D)  elements that are heavier than uranium 
E)  all elements besides hydrogen and helium 
A)  elements that are heavier than iron 
B)  elements that are heavier than carbon 
C)  elements that are heavier than hydrogen 
D)  elements that are heavier than uranium 
E)  all elements besides hydrogen and helium

Question 3

If you could watch a time-lapse movie of the interstellar medium over hundreds of millions of years, what would you see?

Accepted Answer

A)  Gas that is often moving at high speed, particularly after one or more supernovae, and constantly changing form between molecular clouds, atomic hydrogen, and hot, ionized bubbles and superbubbles. 
B)  Gas that changes only in very slow and steady ways, so that the movie would in fact be quite boring. 
C)  The entire disk of the Milky Way would pulsate in and out as it contracts to form stars and then blows out in supernovae and then contracts to form stars again and so on. 
D)  The movie would alternate back and forth between being very bright when there is a lot of gas and very dark when there is very little gas. 
A)  Gas that is often moving at high speed, particularly after one or more supernovae, and constantly changing form between molecular clouds, atomic hydrogen, and hot, ionized bubbles and superbubbles. 
B)  Gas that changes only in very slow and steady ways, so that the movie would in fact be quite boring. 
C)  The entire disk of the Milky Way would pulsate in and out as it contracts to form stars and then blows out in supernovae and then contracts to form stars again and so on. 
D)  The movie would alternate back and forth between being very bright when there is a lot of gas and very dark when there is very little gas.

Question 4

What do halo stars do differently from disk stars?

Accepted Answer

A)  They orbit the galactic center with many different inclinations, while disk stars all orbit in nearly the same plane. 
B)  They remain stationary, quite unlike disk stars that orbit the galactic center. 
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 orbit the galactic center with many different inclinations, while disk stars all orbit in nearly the same plane. 
B)  They remain stationary, quite unlike disk stars that orbit the galactic center. 
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 5

What evidence supports the existence of a black hole at the center of our galaxy?

Accepted Answer

A)  We observe an extremely bright X-ray source at the center of our galaxy. 
B)  We can see gas falling into an accretion disk and past the event horizon of a black hole. 
C)  The motions of the gas and stars at the center indicate that it contains 4 million solar masses within a region only 3 light-years across. 
D)  We observe a large, dark object that absorbs all light at the center of our galaxy. 
E)  all of the above 
A)  We observe an extremely bright X-ray source at the center of our galaxy. 
B)  We can see gas falling into an accretion disk and past the event horizon of a black hole. 
C)  The motions of the gas and stars at the center indicate that it contains 4 million solar masses within a region only 3 light-years across. 
D)  We observe a large, dark object that absorbs all light at the center of our galaxy. 
E)  all of the above

Question 6

If we could see our own galaxy from 2 million light-years away, it would appear ________.

Accepted Answer

A)  as a flattened disk with a central bulge and spiral arms 
B)  as a faintly glowing band of light stretching all the way around the sky 
C)  to fill the sky with widely spaced stars 
D)  like a single, dim star 
A)  as a flattened disk with a central bulge and spiral arms 
B)  as a faintly glowing band of light stretching all the way around the sky 
C)  to fill the sky with widely spaced stars 
D)  like a single, dim star

Question 7

Over time, what is the net effect of the star-gas-star cycle in the Milky Way?

Accepted Answer

A)  The total mass in the galaxy's interstellar medium is gradually increased, and the new gas is continually enriched in heavy elements. 
B)  The total mass in the galaxy's interstellar medium is gradually reduced, and the remaining gas is continually enriched in heavy elements. 
C)  The temperature of the interstellar medium varies between the cool 10-50 degrees (Kelvin) required to form stars and the 2000-30,000 degree (Kelvin) temperatures of the outer layers of the stars that form. But over time, more and more of the interstellar medium remains cool. 
D)  The gas of the interstellar medium is continually depleted in elements heavier than helium. 
E)  There is no net effect to the cycle. Mass in the interstellar medium lost to star formation is exactly replaced by stellar winds and supernova explosions. 
A)  The total mass in the galaxy's interstellar medium is gradually increased, and the new gas is continually enriched in heavy elements. 
B)  The total mass in the galaxy's interstellar medium is gradually reduced, and the remaining gas is continually enriched in heavy elements. 
C)  The temperature of the interstellar medium varies between the cool 10-50 degrees (Kelvin) required to form stars and the 2000-30,000 degree (Kelvin) temperatures of the outer layers of the stars that form. But over time, more and more of the interstellar medium remains cool. 
D)  The gas of the interstellar medium is continually depleted in elements heavier than helium. 
E)  There is no net effect to the cycle. Mass in the interstellar medium lost to star formation is exactly replaced by stellar winds and supernova explosions.

Question 8

The Sun lives in which component of the Milky Way?

Accepted Answer

A)  The bulge 
B)  The disk 
C)  A globular cluster 
D)  The halo 
A)  The bulge 
B)  The disk 
C)  A globular cluster 
D)  The halo

Question 9

The Milky Way looks the same in X-rays as it does at infrared wavelengths.

Accepted Answer

A) True 
 B)False

Question 10

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

Accepted Answer

The bright red color is produced by an e

Question 11

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 12

On a dark summer night in the northern hemisphere, we can see the Milky Way but we can't see the center of the Milky Way. Why not?

Accepted Answer

A)  There are no stars in the center of the Milky Way, just a supermassive black hole. 
B)  The center of the Milky Way does not emit enough visible light. 
C)  We are in the center of the Milky Way. 
D)  Interstellar dust and gas absorb and scatter visible light. 
A)  There are no stars in the center of the Milky Way, just a supermassive black hole. 
B)  The center of the Milky Way does not emit enough visible light. 
C)  We are in the center of the Milky Way. 
D)  Interstellar dust and gas absorb and scatter visible light.

Question 13

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 14

What evidence suggests that most of the mass of the Milky Way is in the form of dark matter?

Accepted Answer

A)  The orbital speeds of stars far from the galactic center are surprisingly high. 
B)  Although dark matter emits no visible light, we have detected its radio emissions. 
C)  Theoretical models of galaxy formation suggest that a galaxy cannot form unless it has at least 10 times as much matter as we see in the Milky Way disk. 
D)  Our view of distant galaxies is often obscured by dark blotches, which are presumably made of dark matter. 
A)  The orbital speeds of stars far from the galactic center are surprisingly high. 
B)  Although dark matter emits no visible light, we have detected its radio emissions. 
C)  Theoretical models of galaxy formation suggest that a galaxy cannot form unless it has at least 10 times as much matter as we see in the Milky Way disk. 
D)  Our view of distant galaxies is often obscured by dark blotches, which are presumably made of dark matter.

Question 15

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

Accepted Answer

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

Question 16

What do we mean by the interstellar medium?

Accepted Answer

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

Question 17

A History of Water: One of the triumphs of 20ᵗʰ century astronomy is a convincing explanation for the origin of the chemical elements. Consider a single water molecule in your body, consisting of two hydrogen atoms and a single oxygen atom. Trace, from the earliest point in time that you can, the history of these atoms. List all of the possible environments in which these particular atoms could have spent time.

Accepted Answer

The history of the hydrogen and oxygen a

Question 18

Compared to our Sun, most stars in the halo are

Accepted Answer

A)  young, red, and dim and have fewer heavy elements. 
B)  young, blue, and bright and have many more heavy elements. 
C)  old, red, and dim and have fewer heavy elements. 
D)  old, red, and dim and have many more heavy elements. 
E)  old, red, and bright and have fewer heavy elements. 
A)  young, red, and dim and have fewer heavy elements. 
B)  young, blue, and bright and have many more heavy elements. 
C)  old, red, and dim and have fewer heavy elements. 
D)  old, red, and dim and have many more heavy elements. 
E)  old, red, and bright and have fewer heavy elements.

Question 19

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 star 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 star 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 20

What is a shock wave?

Accepted Answer

A)  A pressure wave that moves faster than the speed of sound 
B)  A pressure wave that moves slower than the speed of sound 
C)  A pressure wave that moves faster than the speed of light 
D)  An electromagnetic wave that can create electrical shocks 
E)  An electromagnetic wave created when electrons recombine with protons 
A)  A pressure wave that moves faster than the speed of sound 
B)  A pressure wave that moves slower than the speed of sound 
C)  A pressure wave that moves faster than the speed of light 
D)  An electromagnetic wave that can create electrical shocks 
E)  An electromagnetic wave created when electrons recombine with protons

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

What elements do astronomers consider heavy elements?

If you could watch a time-lapse movie of the interstellar medium over hundreds of millions of years, what would you see?

What do halo stars do differently from disk stars?

What evidence supports the existence of a black hole at the center of our galaxy?

If we could see our own galaxy from 2 million light-years away, it would appear ________.

Over time, what is the net effect of the star-gas-star cycle in the Milky Way?

The Sun lives in which component of the Milky Way?

The Milky Way looks the same in X-rays as it does at infrared wavelengths.

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

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

On a dark summer night in the northern hemisphere, we can see the Milky Way but we can't see the center of the Milky Way. Why not?

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

What evidence suggests that most of the mass of the Milky Way is in the form of dark matter?

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

What do we mean by the interstellar medium?

Compared to our Sun, most stars in the halo are

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

What is a shock wave?

Our Place in 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 Planetary Systems: Our Solar System and Beyond

Earth and the Terrestrial Worlds

Jovian Planet Systems

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

Our Star

Surveying the Stars

Star Stuff

Bizarre Stellar Graveyard

Galaxies and the Foundation of Modern Cosmology

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

The Beginning of Time

Life in the Universe

Filters

Exam 14: Our Galaxy

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

What elements do astronomers consider heavy elements?

If you could watch a time-lapse movie of the interstellar medium over hundreds of millions of years, what would you see?

What do halo stars do differently from disk stars?

What evidence supports the existence of a black hole at the center of our galaxy?

If we could see our own galaxy from 2 million light-years away, it would appear ________.

Over time, what is the net effect of the star-gas-star cycle in the Milky Way?

The Sun lives in which component of the Milky Way?

The Milky Way looks the same in X-rays as it does at infrared wavelengths.

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

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

On a dark summer night in the northern hemisphere, we can see the Milky Way but we can't see the center of the Milky Way. Why not?

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

What evidence suggests that most of the mass of the Milky Way is in the form of dark matter?

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

What do we mean by the interstellar medium?

Compared to our Sun, most stars in the halo are

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

What is a shock wave?

Our Place in 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 Planetary Systems: Our Solar System and Beyond

Earth and the Terrestrial Worlds

Jovian Planet Systems

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

Our Star

Surveying the Stars

Star Stuff

Bizarre Stellar Graveyard

Galaxies and the Foundation of Modern Cosmology

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

The Beginning of Time

Life in the Universe

Filters