Question 1

When the universe was __________ old,approximately 24 percent of the normal matter in it had been turned into helium.

Accepted Answer

A)  5 minutes 
B)  8 hours 
C)  1,000 years 
D)  4.5 billion years 
A)  5 minutes 
B)  8 hours 
C)  1,000 years 
D)  4.5 billion years

Question 2

What is the "flatness problem" in cosmology?

Accepted Answer

If the mass and energy density of the un

Question 3

Why would it be very improbable for our universe to have $\varOmega$mass + $\varOmega$$\wedge$ = 0.9?

Accepted Answer

A)  It would quickly evolve to have a much different value of $\varOmega$mass + $\varOmega$$\wedge$. 
B)  In order to exist,every universe must have $\varOmega$mass + $\varOmega$$\wedge$ = 1. 
C)  We know $\varOmega$mass = 1,based on the average density of galaxies. 
D)  The fluctuation in the CBR tells us that $\varOmega$mass + $\varOmega$$\wedge$= 0.7. 
A)  It would quickly evolve to have a much different value of $\varOmega$mass + $\varOmega$$\wedge$. 
B)  In order to exist,every universe must have $\varOmega$mass + $\varOmega$$\wedge$ = 1. 
C)  We know $\varOmega$mass = 1,based on the average density of galaxies. 
D)  The fluctuation in the CBR tells us that $\varOmega$mass + $\varOmega$$\wedge$= 0.7.

Question 4

The figure below shows scale factor RU as a function of time over the age of the universe.Ignoring the presence of dark energy,which curve would represent a flat universe?

Accepted Answer

A)  Curve A 
B)  Curve B 
C)  Curve C 
D)  Curve D 
A)  Curve A 
B)  Curve B 
C)  Curve C 
D)  Curve D

Question 5

What are two observations that when combined tell us that the universe has  $\varOmega$mass + $\varOmega$$\wedge$ = 1 and is flat?

Accepted Answer

Correct answers are any pair o

Question 6

In order from first to last,the specific eras in the universe's history are known as the:

Accepted Answer

A)  primordial,stelliferous,degenerate,and dark eras 
B)  stelliferous,black hole,and entropy eras 
C)  primordial,stelliferous,black hole,and entropy eras 
D)  primordial,stelliferous,degenerate,black hole,and dark eras 
A)  primordial,stelliferous,degenerate,and dark eras 
B)  stelliferous,black hole,and entropy eras 
C)  primordial,stelliferous,black hole,and entropy eras 
D)  primordial,stelliferous,degenerate,black hole,and dark eras

Question 7

The weak force mediates the beta decay of neutrons into protons,electrons,and antineutrinos.

Accepted Answer

A) True 
 B)False

Question 8

Explain why a galaxy can collapse to a much smaller size than its dark matter halo.

Accepted Answer

Dark matter collapses down until it is s

Question 9

Even with infinitely powerful telescopes,we can look back in time only until:

Accepted Answer

A)  when galaxies were first formed 
B)  when hydrogen and helium were formed 
C)  when gravity was quantum mechanical 
D)  the time of recombination 
A)  when galaxies were first formed 
B)  when hydrogen and helium were formed 
C)  when gravity was quantum mechanical 
D)  the time of recombination

Question 10

What process is most responsible for shaping the large-scale structure of the universe?

Accepted Answer

A)  Supernovae from the first generation of stars 
B)  Gravity 
C)  Matter/antimatter annihilation 
D)  Magnetic fields 
A)  Supernovae from the first generation of stars 
B)  Gravity 
C)  Matter/antimatter annihilation 
D)  Magnetic fields

Question 11

About what was the temperature of the universe when a typical CBR photon was no longer able to spontaneously create an electron and positron pair?

Accepted Answer

A)  1000 K 
B)  100,000 K 
C)  1 million K 
D)  1 billion K 
A)  1000 K 
B)  100,000 K 
C)  1 million K 
D)  1 billion K

Question 12

The critical density of the universe is approximately equal to:

Accepted Answer

A)  1 proton/m3 
B)  1 kg/m3 
C)  1 M$\oplus$/m3 
D)  1 M$\odot$ /m3 
A)  1 proton/m3 
B)  1 kg/m3 
C)  1 M$\oplus$/m3 
D)  1 M$\odot$ /m3

Question 13

There are fluctuations in the CBR due to the fact that clumps of dark matter had already begun to form in the universe.

Accepted Answer

A) True 
 B)False

Question 14

Due to the fact that we live in a universe with an accelerating expansion rate,the actual age of the universe is __________ the Hubble time.

Accepted Answer

A)  larger than 
B)  smaller than 
C)  the same as 
D)  independent of 
A)  larger than 
B)  smaller than 
C)  the same as 
D)  independent of

Question 15

Explain why there could be an infinite number of multiverses inside our own universe.Are they likely to be similar or different from our own universe?

Accepted Answer

Because inflation made the universe trem

Question 16

Soon after the Big Bang,we believe the four fundamental forces of nature were united into one superforce,and __________ was the first to split off from the others.

Accepted Answer

A)  the strong force 
B)  electromagnetism 
C)  gravity 
D)  nucleosynthesis 
A)  the strong force 
B)  electromagnetism 
C)  gravity 
D)  nucleosynthesis

Question 17

The ratio of the density in luminous matter to the critical density is 0.3.

Accepted Answer

A) True 
 B)False

Question 18

Which of the following are NOT considered carrier particles used to mediate forces between other particles?

Accepted Answer

A)  Photons 
B)  Gluons 
C)  Quarks 
D)  W+ particles 
A)  Photons 
B)  Gluons 
C)  Quarks 
D)  W+ particles

Question 19

In the superstring theory that successfully unites gravity and quantum mechanics,the universe must have 11 dimensions (10 spatial and 1 temporal).

Accepted Answer

A) True 
 B)False

Question 20

If the sum of the mass and energy density in the universe yields $\varOmega$ < 1 then the universe will recollapse in a Big Crunch.

Accepted Answer

A) True 
 B)False

When the universe was __________ old,approximately 24 percent of the normal matter in it had been turned into helium.

What is the "flatness problem" in cosmology?

Why would it be very improbable for our universe to have $\varOmega$ _mass+ $\varOmega$ _$\wedge$ = 0.9?

The figure below shows scale factor R_U as a function of time over the age of the universe.Ignoring the presence of dark energy,which curve would represent a flat universe?

What are two observations that when combined tell us that the universe has $\varOmega$ _mass+ $\varOmega$ _$\wedge$ = 1 and is flat?

In order from first to last,the specific eras in the universe's history are known as the:

The weak force mediates the beta decay of neutrons into protons,electrons,and antineutrinos.

Explain why a galaxy can collapse to a much smaller size than its dark matter halo.

Even with infinitely powerful telescopes,we can look back in time only until:

What process is most responsible for shaping the large-scale structure of the universe?

About what was the temperature of the universe when a typical CBR photon was no longer able to spontaneously create an electron and positron pair?

The critical density of the universe is approximately equal to:

There are fluctuations in the CBR due to the fact that clumps of dark matter had already begun to form in the universe.

Due to the fact that we live in a universe with an accelerating expansion rate,the actual age of the universe is __________ the Hubble time.

Explain why there could be an infinite number of multiverses inside our own universe.Are they likely to be similar or different from our own universe?

Soon after the Big Bang,we believe the four fundamental forces of nature were united into one superforce,and __________ was the first to split off from the others.

The ratio of the density in luminous matter to the critical density is 0.3.

Which of the following are NOT considered carrier particles used to mediate forces between other particles?

In the superstring theory that successfully unites gravity and quantum mechanics,the universe must have 11 dimensions (10 spatial and 1 temporal).

If the sum of the mass and energy density in the universe yields $\varOmega$ < 1 then the universe will recollapse in a Big Crunch.

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

When the universe was __________ old,approximately 24 percent of the normal matter in it had been turned into helium.

What is the "flatness problem" in cosmology?

Why would it be very improbable for our universe to have Ω\varOmegaΩ mass + Ω\varOmegaΩ ∧\wedge∧ = 0.9?

The figure below shows scale factor RU as a function of time over the age of the universe.Ignoring the presence of dark energy,which curve would represent a flat universe?

What are two observations that when combined tell us that the universe has Ω\varOmegaΩ mass + Ω\varOmegaΩ ∧\wedge∧ = 1 and is flat?

In order from first to last,the specific eras in the universe's history are known as the:

The weak force mediates the beta decay of neutrons into protons,electrons,and antineutrinos.

Explain why a galaxy can collapse to a much smaller size than its dark matter halo.

Even with infinitely powerful telescopes,we can look back in time only until:

What process is most responsible for shaping the large-scale structure of the universe?

About what was the temperature of the universe when a typical CBR photon was no longer able to spontaneously create an electron and positron pair?

The critical density of the universe is approximately equal to:

There are fluctuations in the CBR due to the fact that clumps of dark matter had already begun to form in the universe.

Due to the fact that we live in a universe with an accelerating expansion rate,the actual age of the universe is __________ the Hubble time.

Explain why there could be an infinite number of multiverses inside our own universe.Are they likely to be similar or different from our own universe?

Soon after the Big Bang,we believe the four fundamental forces of nature were united into one superforce,and __________ was the first to split off from the others.

The ratio of the density in luminous matter to the critical density is 0.3.

Which of the following are NOT considered carrier particles used to mediate forces between other particles?

In the superstring theory that successfully unites gravity and quantum mechanics,the universe must have 11 dimensions (10 spatial and 1 temporal).

If the sum of the mass and energy density in the universe yields Ω\varOmegaΩ < 1 then the universe will recollapse in a Big Crunch.

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

Why would it be very improbable for our universe to have $\varOmega$ _mass+ $\varOmega$ _$\wedge$ = 0.9?

The figure below shows scale factor R_U as a function of time over the age of the universe.Ignoring the presence of dark energy,which curve would represent a flat universe?

What are two observations that when combined tell us that the universe has $\varOmega$ _mass+ $\varOmega$ _$\wedge$ = 1 and is flat?

If the sum of the mass and energy density in the universe yields $\varOmega$ < 1 then the universe will recollapse in a Big Crunch.