Question 1

Explain what it means for the universe to be accelerating.How does this compare with the use of the term acceleration in relation to the motion of a single object?

Accepted Answer

When it is said that the universe is acc

Question 2

The "Big Crunch" scenario applies to a universe with

Accepted Answer

A)  a large, positive cosmological constant. 
B)  more black holes than stars. 
C)  a gravitational force that increases with time. 
D)  a density greater than the critical density. 
E)  a density less than the critical density. 
A)  a large, positive cosmological constant. 
B)  more black holes than stars. 
C)  a gravitational force that increases with time. 
D)  a density greater than the critical density. 
E)  a density less than the critical density.

Question 3

Briefly explain the possible scenarios for the fate of the universe assuming that: (a) dark energy decreases in time, (b) it increases in time, and (c) it is a constant.

Accepted Answer

Dark energy is still poorly understood,s

Question 4

What does it mean for a particle to be a mediator?

Accepted Answer

A mediator particle is a parti

Question 5

A grand unified theory (GUT) unites which forces?

Accepted Answer

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

Question 6

Which fundamental force is responsible for chemistry and for holding solids together?

Accepted Answer

A)  electromagnetic 
B)  gravity 
C)  weak nuclear 
D)  dark matter 
E)  strong nuclear 
A)  electromagnetic 
B)  gravity 
C)  weak nuclear 
D)  dark matter 
E)  strong nuclear

Question 7

The figure below illustrates pair production in the early universe, with one particle labeled with a question mark.What type of particle must this be?

Accepted Answer

A)  proton 
B)  electron 
C)  antiproton 
D)  positron 
E)  neutron 
A)  proton 
B)  electron 
C)  antiproton 
D)  positron 
E)  neutron

Question 8

Which of the four fundamental forces enables nuclear fusion inside stars?

Accepted Answer

A)  electromagnetic 
B)  gravity 
C)  weak nuclear 
D)  magnetic 
E)  strong nuclear 
A)  electromagnetic 
B)  gravity 
C)  weak nuclear 
D)  magnetic 
E)  strong nuclear

Question 9

Quantum chromodynamics (QCD) describes how ________ works.

Accepted Answer

A)  gravity 
B)  the strong nuclear force 
C)  electricity 
D)  magnetism 
E)  light 
A)  gravity 
B)  the strong nuclear force 
C)  electricity 
D)  magnetism 
E)  light

Question 10

If someone says, "the laws of the universe must be right for us to exist, because we are here observing it," they are invoking the

Accepted Answer

A)  cosmological principle. 
B)  anthropic principle. 
C)  theory of everything. 
D)  idea of multiverses. 
E)  grand unified theory. 
A)  cosmological principle. 
B)  anthropic principle. 
C)  theory of everything. 
D)  idea of multiverses. 
E)  grand unified theory.

Question 11

What evidence has been found to support the existence of an era of cosmological inflation?

Accepted Answer

A)  Small fluctuations in the cosmic microwave background radiation. 
B)  This era has been directly observed beyond the cosmic microwave background radiation. 
C)  The variation in brightness of Type Ia supernovae provides indirect evidence for inflation. 
D)  Inflation is a result of extrapolating the currently measured changes in dark energy back in time. 
E)  An era of inflation solves several problems in cosmology, but no direct evidence of this era exists. 
A)  Small fluctuations in the cosmic microwave background radiation. 
B)  This era has been directly observed beyond the cosmic microwave background radiation. 
C)  The variation in brightness of Type Ia supernovae provides indirect evidence for inflation. 
D)  Inflation is a result of extrapolating the currently measured changes in dark energy back in time. 
E)  An era of inflation solves several problems in cosmology, but no direct evidence of this era exists.

Question 12

Which of the curves in the figure shown below would best describe the scenario of a Big Crunch for the universe?

Accepted Answer

A)  A 
B)  B 
C)  C 
D)  all three of them 
E)  none of them 
A)  A 
B)  B 
C)  C 
D)  all three of them 
E)  none of them

Question 13

If the material in the universe was at the critical density, expansion would

Accepted Answer

A)  continue at the current rate forever. 
B)  increase at an accelerating rate. 
C)  continually slow, but never quite stop. 
D)  never occur. 
E)  eventually slow, stop, and then reverse. 
A)  continue at the current rate forever. 
B)  increase at an accelerating rate. 
C)  continually slow, but never quite stop. 
D)  never occur. 
E)  eventually slow, stop, and then reverse.

Question 14

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 CMB. 
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 CMB. 
E)  QED combined the electric and magnetic forces.

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 that 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 roll of dice 
D)  a multiverse with constant inflation, where each universe forms due to quantum fluctuations stopping that inflation 
E)  all of these 
A)  parallel universes with different physics and different mathematical explanations 
B)  other parts of an infinite universe that 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 roll of dice 
D)  a multiverse with constant inflation, where each universe forms due to quantum fluctuations stopping that inflation 
E)  all of these

Question 16

According to superstring theory, how are all elementary particles similar? What causes them to have different properties from each other?

Accepted Answer

In superstring theory,all elem

Question 17

In a scenario in which dark energy is changing significantly over time, which of the following outcomes are possible?

Accepted Answer

A)  Big Crunch and Big Rip 
B)  Big Crunch and constant expansion 
C)  Big Rip and Big Freeze 
D)  Big Crunch and Big Freeze 
E)  Big Chill and Big Freeze 
A)  Big Crunch and Big Rip 
B)  Big Crunch and constant expansion 
C)  Big Rip and Big Freeze 
D)  Big Crunch and Big Freeze 
E)  Big Chill and Big Freeze

Question 18

What is the Planck era?

Accepted Answer

A)  the earliest moments after the Big Bang 
B)  the current era of the universe 
C)  the era during which quantum forces evolved into their current form 
D)  the era during which inflation occurred 
E)  the era of human history during which Max Planck's theories dominated physics 
A)  the earliest moments after the Big Bang 
B)  the current era of the universe 
C)  the era during which quantum forces evolved into their current form 
D)  the era during which inflation occurred 
E)  the era of human history during which Max Planck's theories dominated physics

Question 19

Which of the following would represent the unification of all fundamental forces?

Accepted Answer

A)  the electroweak theory 
B)  quantum chromodynamics (QC
D)  
C)  quantum electrodynamics (QE
D)  
D)  grand unified theories (GUT) 
E)  the theory of everything (TO
E)  
A)  the electroweak theory 
B)  quantum chromodynamics (QC
D)  
C)  quantum electrodynamics (QE
D)  
D)  grand unified theories (GUT) 
E)  the theory of everything (TO
E)

Question 20

Explain what the quantum mechanical uncertainty principle means and how it relates to the horizon problem.

Accepted Answer

The uncertainty principle says that,as y

Exam 22: Cosmology

Explain what it means for the universe to be accelerating.How does this compare with the use of the term acceleration in relation to the motion of a single object?

The "Big Crunch" scenario applies to a universe with

Briefly explain the possible scenarios for the fate of the universe assuming that: (a) dark energy decreases in time, (b) it increases in time, and (c) it is a constant.

What does it mean for a particle to be a mediator?

A grand unified theory (GUT) unites which forces?

Which fundamental force is responsible for chemistry and for holding solids together?

The figure below illustrates pair production in the early universe, with one particle labeled with a question mark.What type of particle must this be?

Which of the four fundamental forces enables nuclear fusion inside stars?

Quantum chromodynamics (QCD) describes how ________ works.

If someone says, "the laws of the universe must be right for us to exist, because we are here observing it," they are invoking the

What evidence has been found to support the existence of an era of cosmological inflation?

Which of the curves in the figure shown below would best describe the scenario of a Big Crunch for the universe?

If the material in the universe was at the critical density, expansion would

Which was a triumph of quantum electrodynamics (QED)?

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

According to superstring theory, how are all elementary particles similar? What causes them to have different properties from each other?

In a scenario in which dark energy is changing significantly over time, which of the following outcomes are possible?

What is the Planck era?

Which of the following would represent the unification of all fundamental forces?

Explain what the quantum mechanical uncertainty principle means and how it relates to the horizon problem.

Thinking Like an Astronomer

Patterns in the Skymotions of Earth and the Moon

Motion of Astronomical Bodies

Gravity and Orbits

Light

The Tools of the Astronomer

The Formation of Planetary Systems

The Terrestrial Planets and Earths Moon

Atmospheres of the Terrestrial Planets

Worlds of Gas and Liquidthe Giant Planets

Planetary Moons and Rings

Dwarf Planets and Small Solar System Bodies

Taking the Measure of Stars

Our Starthe Sun

The Interstellar Medium and Star Formation

Evolution of Low-Mass Stars

Evolution of High-Mass Stars

Relativity and Black Holes

Galaxies

The Milky Waya Normal Spiral Galaxy

The Expanding Universe

Large-Scale Structure in the Universe

Life

Filters