Question 1

Which of the following statements comparing halo stars to our Sun is not true?

Accepted Answer

A) Most stars in the halo contain a much lower percentage of heavy elements than the Sun. 
B) Most stars in the halo are less luminous than the Sun. 
C) Most stars in the halo have either died or are in their final stages of life, while the Sun is only in about the middle of its lifetime. 
D) Most stars in the halo have cooler surface temperatures than the Sun. 
A) Most stars in the halo contain a much lower percentage of heavy elements than the Sun. 
B) Most stars in the halo are less luminous than the Sun. 
C) Most stars in the halo have either died or are in their final stages of life, while the Sun is only in about the middle of its lifetime. 
D) Most stars in the halo have cooler surface temperatures than the Sun.

Question 2

What causes the sun to "bob" up- and- down in its orbit around the galactic center?

Accepted Answer

A) gravitational attraction towards other nearby galaxies 
B) lack of friction with the low- density interstellar medium 
C) the localized pull of stars within the disk itself 
D) A and B 
E) B and C 
A) gravitational attraction towards other nearby galaxies 
B) lack of friction with the low- density interstellar medium 
C) the localized pull of stars within the disk itself 
D) A and B 
E) B and C

Question 3

What affects the average orbital speed of a star in our galaxy?

Accepted Answer

A) the mass of the galaxy inside its orbit and the size of its orbit 
B) the star's mass and the mass of the galaxy 
C) the mass and age of the star 
D) the mass and age of the galaxy 
A) the mass of the galaxy inside its orbit and the size of its orbit 
B) the star's mass and the mass of the galaxy 
C) the mass and age of the star 
D) the mass and age of the galaxy

Question 4

The very first stars in the universe were made of

Accepted Answer

A) hydrogen and helium, 0.1% heavy elements. 
B) hydrogen and helium, 2% heavy elements. 
C) hydrogen and helium, 10% heavy elements. 
D) hydrogen and helium. 
A) hydrogen and helium, 0.1% heavy elements. 
B) hydrogen and helium, 2% heavy elements. 
C) hydrogen and helium, 10% heavy elements. 
D) hydrogen and helium.

Question 5

Most of the current star formation in the Milky Way occurs in its spiral arms.

Accepted Answer

A) True 
 B)False

Question 6

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 7

Compared to our Sun, most stars in the halo are

Accepted Answer

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

Question 8

How should we expect the Milky Way's interstellar medium to be different in 50 billion years than it is today?

Accepted Answer

A) The total amount of gas will be much less than it is today. 
B) The total amount of gas will be much greater, since many stars will undergo supernovae between now and then. 
C) Thanks to the recycling of the star- gas- star cycle, the interstellar medium should look about the same in 50 billion years as it does today. 
D) The total amount of gas will be about the same, but the percentage of elements heavier than hydrogen and helium will have risen from the current 2% to more than 50%. 
A) The total amount of gas will be much less than it is today. 
B) The total amount of gas will be much greater, since many stars will undergo supernovae between now and then. 
C) Thanks to the recycling of the star- gas- star cycle, the interstellar medium should look about the same in 50 billion years as it does today. 
D) The total amount of gas will be about the same, but the percentage of elements heavier than hydrogen and helium will have risen from the current 2% to more than 50%.

Question 9

What are cosmic rays?

Accepted Answer

A) lasers used as weapons by extraterrestrials 
B) another name for gamma rays and X- rays 
C) subatomic particles that travel close the speed of light 
D) fast- moving dust particles in the interstellar medium 
E) the highest- energy form of light 
A) lasers used as weapons by extraterrestrials 
B) another name for gamma rays and X- rays 
C) subatomic particles that travel close the speed of light 
D) fast- moving dust particles in the interstellar medium 
E) the highest- energy form of light

Question 10

What is an ionization nebula?

Accepted Answer

A) a region of very hot, low- density gas surrounding a recent supernova 
B) a clump of gas that will soon give birth to a new star 
C) a name sometimes used to describe spiral galaxies besides the Milky Way 
D) a colorful cloud of gas that glows because it is heated by light from nearby hot stars 
A) a region of very hot, low- density gas surrounding a recent supernova 
B) a clump of gas that will soon give birth to a new star 
C) a name sometimes used to describe spiral galaxies besides the Milky Way 
D) a colorful cloud of gas that glows because it is heated by light from nearby hot stars

Question 11

Spectra for the Cygnus loop and the Orion nebula are shown above. Judging from their spectra, how would these two objects look to the naked eye (assuming they were bright enough for colors to be distinguished)?

Accepted Answer

A) The Cygnus loop would appear blue, and the Orion nebula would appear blue. 
B) The Cygnus loop would appear red, and the Orion nebula would appear red. 
C) The Cygnus loop would appear blue, and the Orion nebula would appear red. 
D) The Cygnus loop would appear red, and the Orion nebula would appear blue. 
A) The Cygnus loop would appear blue, and the Orion nebula would appear blue. 
B) The Cygnus loop would appear red, and the Orion nebula would appear red. 
C) The Cygnus loop would appear blue, and the Orion nebula would appear red. 
D) The Cygnus loop would appear red, and the Orion nebula would appear blue.

Question 12

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 changes only in very slow and steady ways, so that the movie would in fact be quite boring 
B) 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. 
C) 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. 
D) 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 
A) Gas that changes only in very slow and steady ways, so that the movie would in fact be quite boring 
B) 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. 
C) 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. 
D) 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

Question 13

Where are most heavy elements made?

Accepted Answer

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

Question 14

The Milky Way looks the same in X- rays as it does at infrared wavelengths. 109)

Accepted Answer

A) True 
 B)False

Question 15

What is the thickness of the disk of the Milky Way?

Accepted Answer

A) 100 light years 
B) 1,000,000 light years 
C) 1,000 light years 
D) 10,000 light years 
E) 100,000 light years 
A) 100 light years 
B) 1,000,000 light years 
C) 1,000 light years 
D) 10,000 light years 
E) 100,000 light years

Question 16

Most stars in the Milky Way's halo are .

Accepted Answer

A) found inside molecular clouds 
B) blue or white in color 
C) very young 
D) very old 
A) found inside molecular clouds 
B) blue or white in color 
C) very young 
D) very old

Question 17

All elements heavier than iron are made during supernova explosions.

Accepted Answer

A) True 
 B)False

Question 18

How would you expect a star that formed recently in the disk of the galaxy to differ from one that formed early in the history of the disk?

Accepted Answer

A) It should be higher in mass. 
B) It should have a higher fraction of elements heavier than hydrogen and helium. 
C) It should orbit the galactic center at a much higher rate of speed. 
D) It should be much brighter. 
E) All of the above would be expected. 
A) It should be higher in mass. 
B) It should have a higher fraction of elements heavier than hydrogen and helium. 
C) It should orbit the galactic center at a much higher rate of speed. 
D) It should be much brighter. 
E) All of the above would be expected.

Question 19

What is the diameter of the disk of the Milky Way?

Accepted Answer

A) 10,000 light years 
B) 1,000 light years 
C) 100,000 light years 
D) 100 light years 
E) 1,000,000 light years 
A) 10,000 light years 
B) 1,000 light years 
C) 100,000 light years 
D) 100 light years 
E) 1,000,000 light years

Question 20

Reflection nebula are bluer than the stars that illuminate them. The Earth's sky is bluer than the Sun. Is this a coincidence? Explain why or why not.

Accepted Answer

Both arise for the same physical reason:

Which of the following statements comparing halo stars to our Sun is not true?

What causes the sun to "bob" up- and- down in its orbit around the galactic center?

What affects the average orbital speed of a star in our galaxy?

The very first stars in the universe were made of

Most of the current star formation in the Milky Way occurs in its spiral arms.

Compared to our Sun, most stars in the halo are

How should we expect the Milky Way's interstellar medium to be different in 50 billion years than it is today?

What are cosmic rays?

What is an ionization nebula?

Spectra for the Cygnus loop and the Orion nebula are shown above. Judging from their spectra, how would these two objects look to the naked eye (assuming they were bright enough for colors to be distinguished)?

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

Where are most heavy elements made?

The Milky Way looks the same in X- rays as it does at infrared wavelengths. 109)

What is the thickness of the disk of the Milky Way?

Most stars in the Milky Way's halo are .

All elements heavier than iron are made during supernova explosions.

How would you expect a star that formed recently in the disk of the galaxy to differ from one that formed early in the history of the disk?

What is the diameter of the disk of the Milky Way?

Reflection nebula are bluer than the stars that illuminate them. The Earth's sky is bluer than the Sun. Is this a coincidence? Explain why or why not.

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

Which of the following statements comparing halo stars to our Sun is not true?

What causes the sun to "bob" up- and- down in its orbit around the galactic center?

What affects the average orbital speed of a star in our galaxy?

The very first stars in the universe were made of

Most of the current star formation in the Milky Way occurs in its spiral arms.

Compared to our Sun, most stars in the halo are

How should we expect the Milky Way's interstellar medium to be different in 50 billion years than it is today?

What are cosmic rays?

What is an ionization nebula?

Spectra for the Cygnus loop and the Orion nebula are shown above. Judging from their spectra, how would these two objects look to the naked eye (assuming they were bright enough for colors to be distinguished)?

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

Where are most heavy elements made?

The Milky Way looks the same in X- rays as it does at infrared wavelengths. 109)

What is the thickness of the disk of the Milky Way?

Most stars in the Milky Way's halo are .

All elements heavier than iron are made during supernova explosions.

How would you expect a star that formed recently in the disk of the galaxy to differ from one that formed early in the history of the disk?

What is the diameter of the disk of the Milky Way?

Reflection nebula are bluer than the stars that illuminate them. The Earth's sky is bluer than the Sun. Is this a coincidence? Explain why or why not.

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