Question 1

A(n) ___________ Universe is infinite and would have a density equal to the critical density.

Accepted Answer

The answer of A(n) ___________ Universe is infinite and would...

Question 2

How old is the Universe since the big bang? Pick the best answer according to radioactive dating in the solar system, light travel times to most distant galaxies, time reversal of the big bang, and observations of the 3-K radiation.

Accepted Answer

A)   1400 years
B)   14,000 years
C)   14,000,000 years
D)   14,000,000,000 years

Question 3

The ___________ view of the Universe is that it is eternal and unchanging.

Accepted Answer

A)   inflationary
B)   accelerating
C)   static
D)   big bang

Question 4

How long is one Hubble time?

Accepted Answer

A)   1/4 the age of the Universe
B)   1/2 the age of the Universe
C)   the age of the Universe
D)   double the age of the Universe

Question 5

The CMB is perfectly uniform.

Accepted Answer

A) True 
 B)False

Question 6

Inflation explains the horizon and flatness problems.

Accepted Answer

A) True 
 B)False

Question 7

After recombination occurred, the Universe was plunged into a period of time known as the ___________, which lasted hundreds of millions of years until the first stars were born.

Accepted Answer

The answer of After recombination occurred, the Universe was plunged...

Question 8

The cosmic background radiation comes from a time

Accepted Answer

A)   when protons and neutrons were first formed.
B)   when the big bang first began to expand.
C)   during the inflationary period.
D)   when gamma rays had enough energy to destroy nuclei.
E)   when electrons began to recombine with nuclei to form atoms.

Question 9

In the first second of the universe, the universe cooled and inflated. A result is a separation of one unified force into four distinct forces.

Accepted Answer

A) True 
 B)False

Question 10

Current evidence suggests that the Universe is

Accepted Answer

A)   flat, infinite, and neither expanding nor contracting.
B)   closed, finite, and slowing its expansion.
C)   open, infinite, and slowing in its expansion.
D)   static with no expansion.
E)   flat, infinite, and accelerating in its expansion.

Question 11

Dark energy is the name of the

Accepted Answer

A)   force that lead to the inflationary period of the Universe.
B)   five-dimensional space of the Universe.
C)   force suspected to cause the current acceleration in the rate of expansion of the Universe.
D)   one of the particles of dark matter related to WIMPs.
E)   the force that holds the proton together.

Question 12

WIMPs are an example of baryonic matter.

Accepted Answer

A) True 
 B)False

Question 13

The flatness problem and horizon problem

Accepted Answer

A)   are solved if there was a sudden inflation of the Universe at time before recombination occurred.
B)   show that the Universe can be described as static and unchanging.
C)   show that dark matter must be a small fraction of the total mass of the Universe.
D)   imply that the Universe was once much colder than it is now.
E)   imply that the inflationary theory is incorrect.

Question 14

The resolution of Olbers's paradox suggests that it gets dark at night because

Accepted Answer

A)   the Universe is not infinite in age.
B)   the Universe is static.
C)   the Universe is closed.
D)   the Universe is not infinite in age and the Universe is static.
E)   All of the other choices are correct.

Question 15

One explanation of the dark sky Olbers's Paradox is that light can reach us only from objects in space out to a distance in light years _______ the age of the universe in years.

Accepted Answer

A)   less than
B)   greater than
C)   equal to
D)   less than or equal to
E)   greater than or equal to

Question 16

How might we tell whether the Universe is open or closed?

Accepted Answer

According to general relativity, the ...

Question 17

Where did the cosmic microwave background (CMB)  come from?

Accepted Answer

A)   photons emitted from the first stars
B)   photons released from hydrogen in our galaxy
C)   light scattered by dust in our Solar System
D)   photons released when electrons and nuclei combined for the first time

Question 18

When a proton and an antiproton collide

Accepted Answer

A)   they destroy each other and produce energy in the form of gamma rays.
B)   one of the protons is converted to a neutron and they form a nucleus consisting of one proton and one neutron.
C)   one of the protons is converted to an electron and they form a hydrogen atom.
D)   one proton is converted to a neutron and the other is converted to an electron.
E)   A proton and an antiproton cannot collide because the Coulomb barrier is too great.

Question 19

A center or an edge of the Universe would be a special place, contradicting the cosmological principle.

Accepted Answer

A) True 
 B)False

Question 20

4 years B)  ˜105 years C)  ˜106 years D)  ˜1 second" class="answers-bank-image d-inline" rel="preload" >
As shown in the above graph, neither radiation nor matter dominated for __________.

Accepted Answer

A)   ˜104 years
B)   ˜105 years
C)   ˜106 years
D)   ˜1 second

Exam 14: Modern Cosmology

One explanation of the dark sky Olbers's Paradox is that light can reach us only from objects in space out to a distance in light years _______ the age of the universe in years.

Correct AnswerverifiedShow Answer

The resolution of Olbers's paradox suggests that it gets dark at night because

Correct AnswerverifiedShow Answer

The CMB is perfectly uniform.

Correct AnswerverifiedShow Answer

Inflation explains the horizon and flatness problems.

Correct AnswerverifiedShow Answer

A center or an edge of the Universe would be a special place, contradicting the cosmological principle.

Correct AnswerverifiedShow Answer

How old is the Universe since the big bang? Pick the best answer according to radioactive dating in the solar system, light travel times to most distant galaxies, time reversal of the big bang, and observations of the 3-K radiation.

Correct AnswerverifiedShow Answer

The ___________ view of the Universe is that it is eternal and unchanging.

Correct AnswerverifiedShow Answer

Dark energy is the name of the

Correct AnswerverifiedShow Answer

WIMPs are an example of baryonic matter.

Correct AnswerverifiedShow Answer

How might we tell whether the Universe is open or closed?

Correct Answerverified​ According to general relativity, the ...View AnswerShow Answer

The flatness problem and horizon problem

Correct AnswerverifiedShow Answer

How long is one Hubble time?

Correct AnswerverifiedShow Answer

When a proton and an antiproton collide

Correct AnswerverifiedShow Answer

After recombination occurred, the Universe was plunged into a period of time known as the ___________, which lasted hundreds of millions of years until the first stars were born.

Correct AnswerverifiedShow Answer

In the first second of the universe, the universe cooled and inflated. A result is a separation of one unified force into four distinct forces.

Correct AnswerverifiedShow Answer

Current evidence suggests that the Universe is

Correct AnswerverifiedShow Answer

As shown in the above graph, neither radiation nor matter dominated for __________.

Correct AnswerverifiedShow Answer

A(n) ___________ Universe is infinite and would have a density equal to the critical density.

Correct AnswerverifiedShow Answer

Where did the cosmic microwave background (CMB) come from?

Correct AnswerverifiedShow Answer

The cosmic background radiation comes from a time

Correct AnswerverifiedShow Answer

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According to general relativity, the ...
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