Question 1

In quantum electrodynamics (QED),what mediates the electromagnetic force between particles?

Accepted Answer

In QED,the electromagnetic force between two objects is determined by all the possible ways in which they can exchange virtual photons.

Question 2

We expect the galaxies that we see at a redshift of 4 will be __________ than galaxies today.

Accepted Answer

A)  more irregular and redder 
B)  larger and redder 
C)  smaller and bluer 
D)  smaller and redder 
A)  more irregular and redder 
B)  larger and redder 
C)  smaller and bluer 
D)  smaller and redder C

Question 3

Which is NOT an ingredient needed to build a cosmological simulation of large-scale structure formation?

Accepted Answer

A)  The spectrum of density fluctuations that quantum mechanics imprints on the early universe 
B)  The density of dark matter and luminous matter in the universe 
C)  The grand unified theory 
D)  The density of dark energy in the universe 
A)  The spectrum of density fluctuations that quantum mechanics imprints on the early universe 
B)  The density of dark matter and luminous matter in the universe 
C)  The grand unified theory 
D)  The density of dark energy in the universe C

Question 4

Current observations suggest that the density of luminous matter ($\varOmega$luminous),all matter ($\varOmega$matter),and dark energy ($\varOmega$$\wedge$)are:

Accepted Answer

A)  "$\varOmega$luminous = 0.1,$\varOmega$matter = 0.3,$\varOmega$$\wedge$ = 0.7" 
B)  "$\varOmega$luminous = 0.02,$\varOmega$matter = 0.5,$\varOmega$$\wedge$ = 0.5" 
C)  "$\varOmega$luminous = 0,$\varOmega$matter = 0.1,$\varOmega$$\wedge$ = 0.9" 
D)  "$\varOmega$luminous = 0.02,$\varOmega$matter = 0.3,$\varOmega$$\wedge$ = 0.7" 
A)  "$\varOmega$luminous = 0.1,$\varOmega$matter = 0.3,$\varOmega$$\wedge$ = 0.7" 
B)  "$\varOmega$luminous = 0.02,$\varOmega$matter = 0.5,$\varOmega$$\wedge$ = 0.5" 
C)  "$\varOmega$luminous = 0,$\varOmega$matter = 0.1,$\varOmega$$\wedge$ = 0.9" 
D)  "$\varOmega$luminous = 0.02,$\varOmega$matter = 0.3,$\varOmega$$\wedge$ = 0.7"

Question 5

We currently find ourselves in the stelliferous era in the history of our universe.

Accepted Answer

A) True 
 B)False

Question 6

Examine the figure below.Why is the universe made up of matter as opposed to antimatter?

Accepted Answer

Following the Big Bang,there w

Question 7

The theory of inflation assumes that at some point in time dark energy will decay and the universe will expand rapidly by a factor of 1030.

Accepted Answer

A) True 
 B)False

Question 8

If $\varOmega$matter + $\varOmega$$\wedge$ = 1 today and dark energy was a cosmological constant,the universe will:

Accepted Answer

A)  expand forever 
B)  slow its expansion but never reverse it 
C)  stop expanding and eventually collapse 
D)  oscillate between expansion and collapse 
A)  expand forever 
B)  slow its expansion but never reverse it 
C)  stop expanding and eventually collapse 
D)  oscillate between expansion and collapse

Question 9

Explain why astronomers cannot accurately model the exact history of the universe in the first few fractions of a second after the Big Bang?

Accepted Answer

At the very moment of its creation,the u

Question 10

During inflation when the universe was approximately 1 second old,its size grew by a factor of 1030.

Accepted Answer

A) True 
 B)False

Question 11

The concept of inflation helps solve both the problems of the flatness of the universe and smoothness of the cosmic background radiation.

Accepted Answer

A) True 
 B)False

Question 12

What do astronomers believe will be the final state of our universe?

Accepted Answer

A)  A "Big Crunch" in which everything collapses back in on itself 
B)  An ever-expanding universe filled with nothing but hydrogen and helium gas 
C)  A universe that stops expanding and is filled with nothing but white dwarfs,neutron stars,and black holes 
D)  An ever-expanding universe filled with photons and elementary particles 
A)  A "Big Crunch" in which everything collapses back in on itself 
B)  An ever-expanding universe filled with nothing but hydrogen and helium gas 
C)  A universe that stops expanding and is filled with nothing but white dwarfs,neutron stars,and black holes 
D)  An ever-expanding universe filled with photons and elementary particles

Question 13

Inflation happened:

Accepted Answer

A)  when the universe was -33 s old 
B)  when the universe expanded by a factor of approximately 1030 
C)  when the average energy of the vacuum of spacetime changed 
D)  all of the above 
A)  when the universe was -33 s old 
B)  when the universe expanded by a factor of approximately 1030 
C)  when the average energy of the vacuum of spacetime changed 
D)  all of the above

Question 14

What is the main reason that astrophysicists cannot calculate the evolution of galaxies exactly?

Accepted Answer

Star formation is not well und

Question 15

Dark energy is a force that continually decreases the expansion rate of the universe.

Accepted Answer

A) True 
 B)False

Question 16

How does the addition of a nonzero cosmological constant affect the expansion of the universe?

Accepted Answer

A)  It is possible for the mass density of the universe to be below the critical density and still collapse. 
B)  It is possible for the density of the universe to be below the critical density and still expand forever. 
C)  It is impossible to have a collapsing universe,regardless of its density. 
D)  It is impossible to have an expanding universe,regardless of its density. 
A)  It is possible for the mass density of the universe to be below the critical density and still collapse. 
B)  It is possible for the density of the universe to be below the critical density and still expand forever. 
C)  It is impossible to have a collapsing universe,regardless of its density. 
D)  It is impossible to have an expanding universe,regardless of its density.

Question 17

If dark energy were to instantly cease,our universe would continue to expand forever.

Accepted Answer

A) True 
 B)False

Question 18

The four fundamental forces of nature are gravity,electromagnetism,the weak force,and the strong force.

Accepted Answer

A) True 
 B)False

Question 19

The ratio of the average density in all forms of matter (luminous and dark)in our universe to the critical density is approximately 0.3.

Accepted Answer

A) True 
 B)False

Question 20

Describe the four fundamental forces of nature by listing their names and describing what effect each force has on objects in the universe.

Accepted Answer

The four fundamental forces of nature ar

In quantum electrodynamics (QED),what mediates the electromagnetic force between particles?

We expect the galaxies that we see at a redshift of 4 will be __________ than galaxies today.

Which is NOT an ingredient needed to build a cosmological simulation of large-scale structure formation?

Current observations suggest that the density of luminous matter ( $\varOmega$ _luminous),all matter ( $\varOmega$ _matter),and dark energy ( $\varOmega$ _$\wedge$)are:

We currently find ourselves in the stelliferous era in the history of our universe.

Examine the figure below.Why is the universe made up of matter as opposed to antimatter?

The theory of inflation assumes that at some point in time dark energy will decay and the universe will expand rapidly by a factor of 10³⁰.

If $\varOmega$ _matter+ $\varOmega$ _$\wedge$ = 1 today and dark energy was a cosmological constant,the universe will:

Explain why astronomers cannot accurately model the exact history of the universe in the first few fractions of a second after the Big Bang?

During inflation when the universe was approximately 1 second old,its size grew by a factor of 10³⁰.

The concept of inflation helps solve both the problems of the flatness of the universe and smoothness of the cosmic background radiation.

What do astronomers believe will be the final state of our universe?

Inflation happened:

What is the main reason that astrophysicists cannot calculate the evolution of galaxies exactly?

Dark energy is a force that continually decreases the expansion rate of the universe.

How does the addition of a nonzero cosmological constant affect the expansion of the universe?

If dark energy were to instantly cease,our universe would continue to expand forever.

The four fundamental forces of nature are gravity,electromagnetism,the weak force,and the strong force.

The ratio of the average density in all forms of matter (luminous and dark)in our universe to the critical density is approximately 0.3.

Describe the four fundamental forces of nature by listing their names and describing what effect each force has on objects in the universe.

Our Place in the Universe

Patterns in the Skymotions of Earth

Laws of Motion

Light and Telescopes

The Formation of Stars and Planets

Terrestrial Worlds in the Inner Solar System

Atmospheres of Venus, Earth, and Mars

The Giant Planets

Small Bodies of the Solar System

Measuring the Stars

Our Star: The Sun

Evolution of Low-Mass Stars

Evolution of High-Mass Stars

The Expansion of Space

The Realm of the Galaxies

Our Galaxy: The Milky Way

Life in the Universe

Filters

Exam 17: Modern Cosmology and the Origin of Structure

In quantum electrodynamics (QED),what mediates the electromagnetic force between particles?

We expect the galaxies that we see at a redshift of 4 will be __________ than galaxies today.

Which is NOT an ingredient needed to build a cosmological simulation of large-scale structure formation?

Current observations suggest that the density of luminous matter ( Ω\varOmegaΩ luminous),all matter ( Ω\varOmegaΩ matter),and dark energy ( Ω\varOmegaΩ ∧\wedge∧ )are:

We currently find ourselves in the stelliferous era in the history of our universe.

Examine the figure below.Why is the universe made up of matter as opposed to antimatter?

The theory of inflation assumes that at some point in time dark energy will decay and the universe will expand rapidly by a factor of 1030.

If Ω\varOmegaΩ matter + Ω\varOmegaΩ ∧\wedge∧ = 1 today and dark energy was a cosmological constant,the universe will:

Explain why astronomers cannot accurately model the exact history of the universe in the first few fractions of a second after the Big Bang?

During inflation when the universe was approximately 1 second old,its size grew by a factor of 1030.

The concept of inflation helps solve both the problems of the flatness of the universe and smoothness of the cosmic background radiation.

What do astronomers believe will be the final state of our universe?

Inflation happened:

What is the main reason that astrophysicists cannot calculate the evolution of galaxies exactly?

Dark energy is a force that continually decreases the expansion rate of the universe.

How does the addition of a nonzero cosmological constant affect the expansion of the universe?

If dark energy were to instantly cease,our universe would continue to expand forever.

The four fundamental forces of nature are gravity,electromagnetism,the weak force,and the strong force.

The ratio of the average density in all forms of matter (luminous and dark)in our universe to the critical density is approximately 0.3.

Describe the four fundamental forces of nature by listing their names and describing what effect each force has on objects in the universe.

Our Place in the Universe

Patterns in the Skymotions of Earth

Laws of Motion

Light and Telescopes

The Formation of Stars and Planets

Terrestrial Worlds in the Inner Solar System

Atmospheres of Venus, Earth, and Mars

The Giant Planets

Small Bodies of the Solar System

Measuring the Stars

Our Star: The Sun

Evolution of Low-Mass Stars

Evolution of High-Mass Stars

The Expansion of Space

The Realm of the Galaxies

Our Galaxy: The Milky Way

Life in the Universe

Filters

Current observations suggest that the density of luminous matter ( $\varOmega$ _luminous),all matter ( $\varOmega$ _matter),and dark energy ( $\varOmega$ _$\wedge$)are:

The theory of inflation assumes that at some point in time dark energy will decay and the universe will expand rapidly by a factor of 10³⁰.

If $\varOmega$ _matter+ $\varOmega$ _$\wedge$ = 1 today and dark energy was a cosmological constant,the universe will:

During inflation when the universe was approximately 1 second old,its size grew by a factor of 10³⁰.