Question 1

Which of the following correctly characterizes the composition of our Universe?

Accepted Answer

A)  5 percent normal matter, 68 percent dark matter, 27 percent dark energy 
B)  27 percent normal matter, 5 percent dark matter, 68 percent dark energy 
C)  5 percent normal matter, 27 percent dark matter, 68 percent dark energy 
D)  27 percent normal matter, 68 percent dark matter, 5 percent dark energy 
A)  5 percent normal matter, 68 percent dark matter, 27 percent dark energy 
B)  27 percent normal matter, 5 percent dark matter, 68 percent dark energy 
C)  5 percent normal matter, 27 percent dark matter, 68 percent dark energy 
D)  27 percent normal matter, 68 percent dark matter, 5 percent dark energy

Question 2

What is the total density parameter of our Universe?

Accepted Answer

A)  W = 0.1 
B)  W = 0.3 
C)  W = 1 
D)  W = 2 
A)  W = 0.1 
B)  W = 0.3 
C)  W = 1 
D)  W = 2

Question 3

To what precision have astronomers measured the dark matter density of the Universe?

Accepted Answer

To within

Question 4

Which of the following factors prevents protons and electrons from recombining in the early phases of the Universe's history?

Accepted Answer

A)  Photons have too much energy. 
B)  Protons and electrons do not have enough energy. 
C)  Protons and electrons are too far apart to collide. 
D)  Protons and electrons have too high of a temperature for gravity to attract them. 
A)  Photons have too much energy. 
B)  Protons and electrons do not have enough energy. 
C)  Protons and electrons are too far apart to collide. 
D)  Protons and electrons have too high of a temperature for gravity to attract them.

Question 5

A theory of quantum gravity is necessary to describe:

Accepted Answer

A)  baryogenesis. 
B)  the cosmic singularity. 
C)  observations of distant supernovas. 
D)  all of the above. 
A)  baryogenesis. 
B)  the cosmic singularity. 
C)  observations of distant supernovas. 
D)  all of the above.

Question 6

What is goal of cosmology?

Accepted Answer

To study the Univers

Question 7

Which of the following elements has an observed abundance that supports the Big Bang model?

Accepted Answer

A)  iron 
B)  helium 
C)  oxygen 
D)  nitrogen 
A)  iron 
B)  helium 
C)  oxygen 
D)  nitrogen

Question 8

Why does measuring the matter and energy content of the Universe tell astronomers how the curvature of space is changing?

Accepted Answer

Because general rela

Question 9

Why is the size distribution of temperature fluctuations on the cosmic microwave background useful to astronomers?

Accepted Answer

A)  It shows that the Universe is mostly opaque at the present day. 
B)  It shows that the cosmological principle is not accurate. 
C)  It shows how recombination occurred differently in different parts of the Universe. 
D)  It allows precise measurements of the density of dark energy. 
A)  It shows that the Universe is mostly opaque at the present day. 
B)  It shows that the cosmological principle is not accurate. 
C)  It shows how recombination occurred differently in different parts of the Universe. 
D)  It allows precise measurements of the density of dark energy.

Question 10

The figure below shows how two electrons,traveling from left to right on the diagram,repel each other.What quantum particle causes the electrons to change direction?

Accepted Answer

The answer of The figure below shows how two electrons,traveling...

Question 11

If dark energy continues to dominate the expansion of the Universe,it will:

Accepted Answer

A)  recollapse. 
B)  decelerate until it stops expanding. 
C)  accelerate for a time and then recollapse. 
D)  enter another inflationary era. 
A)  recollapse. 
B)  decelerate until it stops expanding. 
C)  accelerate for a time and then recollapse. 
D)  enter another inflationary era.

Question 12

What process explains why the cosmic microwave background has nearly the same temperature in every direction on the sky?

Accepted Answer

A)  recombination 
B)  inflation 
C)  decoupling 
D)  redshifting 
A)  recombination 
B)  inflation 
C)  decoupling 
D)  redshifting

Question 13

How does the Universe's expansion during the inflationary era differ from that in the classic Big Bang model?

Accepted Answer

A)  During inflation, the curvature of the Universe changes. 
B)  During inflation, regions initially outside of causal contact are allowed to interact with each other. 
C)  During inflation, Hubble's law is violated. 
D)  During inflation, expansion makes the density closer to the critical value. 
A)  During inflation, the curvature of the Universe changes. 
B)  During inflation, regions initially outside of causal contact are allowed to interact with each other. 
C)  During inflation, Hubble's law is violated. 
D)  During inflation, expansion makes the density closer to the critical value.

Question 14

Radiation from the first 400,000 years of the Universe's history can be observed as:

Accepted Answer

A)  optical line radiation. 
B)  microwaves. 
C)  X-rays. 
D)  gamma rays. 
A)  optical line radiation. 
B)  microwaves. 
C)  X-rays. 
D)  gamma rays.

Question 15

When the cosmic microwave background was produced,it was a blackbody with a temperature of 4,000 K.Today,we observe it to have a temperature of 2.7 K.By approximately what factor has the Universe expanded between those two time periods?

Accepted Answer

A)  300 
B)  1,000 
C)  3,000 
D)  7,000 
A)  300 
B)  1,000 
C)  3,000 
D)  7,000

Question 16

The cosmic singularity describes:

Accepted Answer

A)  the initial conditions of the Big Bang model. 
B)  the equilibrium state toward which the Big Bang model approaches. 
C)  the opacity of the Universe in the first few minutes after the Big Bang. 
D)  our Universe's place within the multiverse. 
A)  the initial conditions of the Big Bang model. 
B)  the equilibrium state toward which the Big Bang model approaches. 
C)  the opacity of the Universe in the first few minutes after the Big Bang. 
D)  our Universe's place within the multiverse.

Question 17

Why is the cosmic microwave background a blackbody?

Accepted Answer

A)  because it was in equilibrium with matter in the early Universe 
B)  because it no longer interacts with matter 
C)  because it has redshifted so much 
D)  because of inflation 
A)  because it was in equilibrium with matter in the early Universe 
B)  because it no longer interacts with matter 
C)  because it has redshifted so much 
D)  because of inflation

Question 18

The figure below shows a map of the temperature of the cosmic microwave background.The features shown here are instrumental in forming:

Accepted Answer

A)  black holes. 
B)  baryons. 
C)  nuclei. 
D)  the cosmic web. 
A)  black holes. 
B)  baryons. 
C)  nuclei. 
D)  the cosmic web.

Question 19

An astronomer discovers that brightnesses of distant supernovas do not precisely obey Hubble's law (shown by the middle curve in the figure below)but instead follow the uppermost curve.What should he or she infer?

Accepted Answer

The Univer

Question 20

The figure below shows a phase transition in the early Universe.What kinds of particles were created during this transition?

Accepted Answer

A)  inflatons 
B)  baryons 
C)  nuclei 
D)  atoms 
A)  inflatons 
B)  baryons 
C)  nuclei 
D)  atoms

Which of the following correctly characterizes the composition of our Universe?

What is the total density parameter of our Universe?

To what precision have astronomers measured the dark matter density of the Universe?

Which of the following factors prevents protons and electrons from recombining in the early phases of the Universe's history?

A theory of quantum gravity is necessary to describe:

What is goal of cosmology?

Which of the following elements has an observed abundance that supports the Big Bang model?

Why does measuring the matter and energy content of the Universe tell astronomers how the curvature of space is changing?

Why is the size distribution of temperature fluctuations on the cosmic microwave background useful to astronomers?

The figure below shows how two electrons,traveling from left to right on the diagram,repel each other.What quantum particle causes the electrons to change direction?

If dark energy continues to dominate the expansion of the Universe,it will:

What process explains why the cosmic microwave background has nearly the same temperature in every direction on the sky?

How does the Universe's expansion during the inflationary era differ from that in the classic Big Bang model?

Radiation from the first 400,000 years of the Universe's history can be observed as:

When the cosmic microwave background was produced,it was a blackbody with a temperature of 4,000 K.Today,we observe it to have a temperature of 2.7 K.By approximately what factor has the Universe expanded between those two time periods?

The cosmic singularity describes:

Why is the cosmic microwave background a blackbody?

The figure below shows a map of the temperature of the cosmic microwave background.The features shown here are instrumental in forming:

An astronomer discovers that brightnesses of distant supernovas do not precisely obey Hubble's law (shown by the middle curve in the figure below)but instead follow the uppermost curve.What should he or she infer?

The figure below shows a phase transition in the early Universe.What kinds of particles were created during this transition?

Getting Started: Science, astronomy, and Being Human

A Universe Made, a Universe Discovered

A Universe of Universal Laws

A Universe of Universal Laws

The Architecture and Birth of Planetary Systems

Home Base: Earth and Moon

Sibling Worlds: Mercury, Venus, and Mars

Gas, ice, and Stone: the Outer Planets

Life and the Search for Habitable Worlds

The Sun As a Star

Measuring the Stars: the Main Sequence and Its Meaning

Nursery of the Stars: the Interstellar Medium and Star Formation

To the Graveyard of Stars: the End Points of Stellar Evolution

Down the Rabbit Hole: Relativity and Black Holes

Our City of Stars: the Milky Way

A Universe of Galaxies

The Cosmic Web: the Large-Scale Structure of the Universe

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Exam 18: Cosmology

Which of the following correctly characterizes the composition of our Universe?

What is the total density parameter of our Universe?

To what precision have astronomers measured the dark matter density of the Universe?

Which of the following factors prevents protons and electrons from recombining in the early phases of the Universe's history?

A theory of quantum gravity is necessary to describe:

What is goal of cosmology?

Which of the following elements has an observed abundance that supports the Big Bang model?

Why does measuring the matter and energy content of the Universe tell astronomers how the curvature of space is changing?

Why is the size distribution of temperature fluctuations on the cosmic microwave background useful to astronomers?

The figure below shows how two electrons,traveling from left to right on the diagram,repel each other.What quantum particle causes the electrons to change direction?

If dark energy continues to dominate the expansion of the Universe,it will:

What process explains why the cosmic microwave background has nearly the same temperature in every direction on the sky?

How does the Universe's expansion during the inflationary era differ from that in the classic Big Bang model?

Radiation from the first 400,000 years of the Universe's history can be observed as:

When the cosmic microwave background was produced,it was a blackbody with a temperature of 4,000 K.Today,we observe it to have a temperature of 2.7 K.By approximately what factor has the Universe expanded between those two time periods?

The cosmic singularity describes:

Why is the cosmic microwave background a blackbody?

The figure below shows a map of the temperature of the cosmic microwave background.The features shown here are instrumental in forming:

An astronomer discovers that brightnesses of distant supernovas do not precisely obey Hubble's law (shown by the middle curve in the figure below)but instead follow the uppermost curve.What should he or she infer?

The figure below shows a phase transition in the early Universe.What kinds of particles were created during this transition?

Getting Started: Science, astronomy, and Being Human

A Universe Made, a Universe Discovered

A Universe of Universal Laws

A Universe of Universal Laws

The Architecture and Birth of Planetary Systems

Home Base: Earth and Moon

Sibling Worlds: Mercury, Venus, and Mars

Gas, ice, and Stone: the Outer Planets

Life and the Search for Habitable Worlds

The Sun As a Star

Measuring the Stars: the Main Sequence and Its Meaning

Nursery of the Stars: the Interstellar Medium and Star Formation

To the Graveyard of Stars: the End Points of Stellar Evolution

Down the Rabbit Hole: Relativity and Black Holes

Our City of Stars: the Milky Way

A Universe of Galaxies

The Cosmic Web: the Large-Scale Structure of the Universe

Filters