Question 1

A grand unified theory unites which forces?

Accepted Answer

A) only electromagnetism,weak nuclear,and strong nuclear forces 
B) only gravity and strong nuclear forces 
C) only electromagnetism,gravity,and weak nuclear forces 
D) only gravity and electromagnetism forces 
E) all four known forces 
A) only electromagnetism,weak nuclear,and strong nuclear forces 
B) only gravity and strong nuclear forces 
C) only electromagnetism,gravity,and weak nuclear forces 
D) only gravity and electromagnetism forces 
E) all four known forces

Question 2

The observations that show that the expansion of the universe is speeding up tell us the universe must contain:

Accepted Answer

A) gravity 
B) dark matter 
C) a force opposing gravity 
D) black holes 
E) cosmic microwave background radiation 
A) gravity 
B) dark matter 
C) a force opposing gravity 
D) black holes 
E) cosmic microwave background radiation

Question 3

Why is the fact that the cosmic microwave background radiation (CMB)is very smooth considered a problem?

Accepted Answer

A) A universe as smooth as predicted by the CMB should not have formed as many galaxies as have been observed. 
B) A universe as smooth as predicted by the CMB should have collapsed by now. 
C) A universe as smooth as predicted by the CMB should be expanding much faster than we are now. 
D) A universe as smooth as predicted by the CMB should never occur because quantum mechanical fluctuations would have been imprinted on it. 
E) A universe as smooth as predicted by the CMB should never have formed any stars or galaxies. 
A) A universe as smooth as predicted by the CMB should not have formed as many galaxies as have been observed. 
B) A universe as smooth as predicted by the CMB should have collapsed by now. 
C) A universe as smooth as predicted by the CMB should be expanding much faster than we are now. 
D) A universe as smooth as predicted by the CMB should never occur because quantum mechanical fluctuations would have been imprinted on it. 
E) A universe as smooth as predicted by the CMB should never have formed any stars or galaxies.

Question 4

According to superstring theory,how are different varieties of elementary particles similar? How do they differ?

Accepted Answer

In superstring theory,all elem

Question 5

Which was a triumph of quantum electrodynamics (QED)?

Accepted Answer

A) QED predicted the existence of three carrier particles before they were discovered in laboratory experiments. 
B) QED unites the strong and weak nuclear forces. 
C) QED is an example of a theory of everything. 
D) QED successfully explains the origin of quantum mechanical fluctuations in the CBR. 
E) QED combined the electric and magnetic forces. 
A) QED predicted the existence of three carrier particles before they were discovered in laboratory experiments. 
B) QED unites the strong and weak nuclear forces. 
C) QED is an example of a theory of everything. 
D) QED successfully explains the origin of quantum mechanical fluctuations in the CBR. 
E) QED combined the electric and magnetic forces.

Question 6

Which of the following is a FALSE statement about inflation?

Accepted Answer

A) Inflation occurred when the universe was −33 seconds old. 
B) Inflation occurred when the universe expanded by a factor of approximately 1030. 
C) Inflation solves the horizon problem. 
D) Inflation is currently driving the expansion of the universe. 
E) Inflation solves the flatness problem. 
A) Inflation occurred when the universe was −33 seconds old. 
B) Inflation occurred when the universe expanded by a factor of approximately 1030. 
C) Inflation solves the horizon problem. 
D) Inflation is currently driving the expansion of the universe. 
E) Inflation solves the flatness problem.

Question 7

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 8

If dark energy is currently causing the expansion rate of the universe to increase with time,does this mean that you should worry that the Sun,the Earth,and your body itself are expanding? Why or why not?

Accepted Answer

Dark energy is indeed causing space to e

Question 9

If gravity were slowing down the expansion of the universe,how would very distant galaxies differ from nearby galaxies?

Accepted Answer

A) Distant galaxies would have a larger value for H0 than nearby galaxies. 
B) Distant galaxies would have a smaller value for H0 than nearby galaxies. 
C) Distant galaxies would contain more dark energy than nearby galaxies. 
D) Distant galaxies would contain less dark energy than nearby galaxies. 
E) Distant and nearby galaxies would be the same. 
A) Distant galaxies would have a larger value for H0 than nearby galaxies. 
B) Distant galaxies would have a smaller value for H0 than nearby galaxies. 
C) Distant galaxies would contain more dark energy than nearby galaxies. 
D) Distant galaxies would contain less dark energy than nearby galaxies. 
E) Distant and nearby galaxies would be the same.

Question 10

If there were enough mass to slow down the expansion rate of the universe,how would the Hubble constant measured using very distant galaxies be different from what is observed in galaxies that are closer to us? Explain your answer.Is this what we observe in our universe?

Accepted Answer

If the universe were slowing down,it mus

Question 11

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 12

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

Accepted Answer

A) True 
 B)False

Question 13

Why does a unified force split to become two separate forces?

Accepted Answer

A) The universe expands so much that carrier particles become too dense. 
B) The average energy of photons in the universe becomes less than the mass of the unified force's carrier particles. 
C) Dark energy becomes significant at later times and forces the two to split. 
D) The spatial dimensions split and so must the forces. 
E) Too many particles are created for the unified force to manage. 
A) The universe expands so much that carrier particles become too dense. 
B) The average energy of photons in the universe becomes less than the mass of the unified force's carrier particles. 
C) Dark energy becomes significant at later times and forces the two to split. 
D) The spatial dimensions split and so must the forces. 
E) Too many particles are created for the unified force to manage.

Question 14

If Ωmass = 0.5 today and there were no dark energy,the universe would:

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 
E) expand so quickly that the universe is ripped apart 
A) expand forever 
B) slow its expansion but never reverse it 
C) stop expanding and eventually collapse 
D) oscillate between expansion and collapse 
E) expand so quickly that the universe is ripped apart

Question 15

Which of these are possible types of multiple universes that could exist?

Accepted Answer

A) parallel universes with different physics and different mathematical explanations 
B) other parts of an infinite universe which are so far away that we cannot observe them 
C) quantum mechanical parallel universes,which are created each time something happens that has a probability of occurring in a different way,such as a dice roll 
D) a multiverse with constant inflation,where each universe forms due to quantum fluctuations stopping that inflation 
E) all of the above 
A) parallel universes with different physics and different mathematical explanations 
B) other parts of an infinite universe which are so far away that we cannot observe them 
C) quantum mechanical parallel universes,which are created each time something happens that has a probability of occurring in a different way,such as a dice roll 
D) a multiverse with constant inflation,where each universe forms due to quantum fluctuations stopping that inflation 
E) all of the above

Question 16

The fact that the currently observed Ωmass + ΩΛ is very close to 1 means that its value has always been very close to 1.

Accepted Answer

A) True 
 B)False

Question 17

Why does the critical mass density of the universe depend on the value of Hubble's constant,H0?

Accepted Answer

H₀ is an indication of how fast

Question 18

Grand unified theories are very attractive because they can explain:

Accepted Answer

A) why we have five fundamental forces in the universe today 
B) why the Big Bang never made any antimatter 
C) why the universe consists mostly of matter 
D) why the CMB is very smooth 
E) what happens inside a black hole 
A) why we have five fundamental forces in the universe today 
B) why the Big Bang never made any antimatter 
C) why the universe consists mostly of matter 
D) why the CMB is very smooth 
E) what happens inside a black hole

Question 19

Why does the sum of Ωmass and ΩΛ determine the shape of our universe?

Accepted Answer

The mass and energy density af

Question 20

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

Exam 22: Modern Cosmology

A grand unified theory unites which forces?

The observations that show that the expansion of the universe is speeding up tell us the universe must contain:

Why is the fact that the cosmic microwave background radiation (CMB)is very smooth considered a problem?

According to superstring theory,how are different varieties of elementary particles similar? How do they differ?

Which was a triumph of quantum electrodynamics (QED)?

Which of the following is a FALSE statement about inflation?

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

If dark energy is currently causing the expansion rate of the universe to increase with time,does this mean that you should worry that the Sun,the Earth,and your body itself are expanding? Why or why not?

If gravity were slowing down the expansion of the universe,how would very distant galaxies differ from nearby galaxies?

If there were enough mass to slow down the expansion rate of the universe,how would the Hubble constant measured using very distant galaxies be different from what is observed in galaxies that are closer to us? Explain your answer.Is this what we observe in our universe?

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.

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

Why does a unified force split to become two separate forces?

If Ωmass = 0.5 today and there were no dark energy,the universe would:

Which of these are possible types of multiple universes that could exist?

The fact that the currently observed Ωmass + ΩΛ is very close to 1 means that its value has always been very close to 1.

Why does the critical mass density of the universe depend on the value of Hubble's constant,H0?

Grand unified theories are very attractive because they can explain:

Why does the sum of Ωmass and ΩΛ determine the shape of our universe?

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

Why Learn Astronomy

Patterns in the Skymotions of Earth

Motion of Astronomical Bodies

Gravity and Orbits

Light

The Tools of the Astronomer

The Birth and Evolution of Planetary Systems

The Terrestrial Planets and Earths Moon

Atmospheres of the Terrestrial Planets

Worlds of Gas and Liquid the Giant Planets

Planetary Adornments Moons and Rings

Dwarf Planets and Small Solar System Bodies

Taking the Measure of Stars

Our Starthe Sun

Star Formation and the Interstellar Medium

Evolution of Low-Mass Stars

Evolution of High-Mass Stars

Relativity and Black Holes

The Expanding Universe

Galaxies

The Milky Waya Normal Spiral Galaxy

Large-Scale Structure in the Universe

Life

Filters

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

If Ω_mass = 0.5 today and there were no dark energy,the universe would:

The fact that the currently observed Ω_mass + Ω_Λ is very close to 1 means that its value has always been very close to 1.

Why does the critical mass density of the universe depend on the value of Hubble's constant,H₀?

Why does the sum of Ω_mass and Ω_Λ determine the shape of our universe?