Question 1

Why does the Big Bang theory predict that the cosmic background radiation should have a perfect thermal radiation spectrum?

Accepted Answer

A)  The background radiation came from the heat of the universe, with a peak corresponding to the temperature of the universe. 
B)  The spectrum of pure hydrogen gas must be a perfect thermal radiation spectrum. 
C)  The spectrum of 75 percent hydrogen and 25 percent helium must be a perfect thermal radiation spectrum. 
D)  The light from all the stars and gas in the sky averaged over the entire universe will be a perfect thermal radiation spectrum. 
E)  It doesn't predict that the cosmic background radiation should have a perfect thermal radiation spectrum. 
A)  The background radiation came from the heat of the universe, with a peak corresponding to the temperature of the universe. 
B)  The spectrum of pure hydrogen gas must be a perfect thermal radiation spectrum. 
C)  The spectrum of 75 percent hydrogen and 25 percent helium must be a perfect thermal radiation spectrum. 
D)  The light from all the stars and gas in the sky averaged over the entire universe will be a perfect thermal radiation spectrum. 
E)  It doesn't predict that the cosmic background radiation should have a perfect thermal radiation spectrum. A

Question 2

Which adjective does not necessarily describe a known feature of the early universe? (Be sure to consider the universe as a whole, not just the observable universe.)

Accepted Answer

A)  Small 
B)  Dense 
C)  Hot 
D)  Filled with intense radiation 
A)  Small 
B)  Dense 
C)  Hot 
D)  Filled with intense radiation A

Question 3

GUT theories predict that protons will eventually decay, causing all solid objects in the universe to fall apart if the universe keeps expanding forever.

Accepted Answer

A) True 
 B)False  True

Question 4

Refer to this scenario for the following questions:
A multi-dimensional being reaches down to Earth and pulls you out of the universe. You are then thrown back into the universe at a place and time of the being's choosing, and you are permitted to leave only after you have identified your surroundings. This process is repeated several times. Through a scientifically unexplainable miracle, you are able to survive in every one of the places that you find yourself. In each scenario below, identify your surroundings (and potentially your cosmic era) from among the choices given.
-You are on the surface of an object, and you have a fairly clear view out into space. Unfortunately, you are also very squashed. The light you observe from distant objects is slightly blueshifted. The surface of the object is composed primarily of carbon and oxygen, and the distance to the horizon seems about the same as that on Earth. By observing the sky for a few weeks, you realize that there are several planets orbiting your object. Where are you?

Accepted Answer

A)  You are on the surface of the Earth. 
B)  You are on the surface of a planet that is somewhat more massive than the Earth. 
C)  You are on the surface of a white dwarf. 
D)  You are "on" an accretion disk around a black hole. 
E)  You are on the surface of a neutron star. 
A)  You are on the surface of the Earth. 
B)  You are on the surface of a planet that is somewhat more massive than the Earth. 
C)  You are on the surface of a white dwarf. 
D)  You are "on" an accretion disk around a black hole. 
E)  You are on the surface of a neutron star.

Question 5

What do we mean by inflation?

Accepted Answer

A)  The expansion of universe starting with the instant after the Big Bang 
B)  A sudden expansion of the universe driven by the energy released when the strong and electroweak forces froze out from the GUT force 
C)  The rapid expansion of the universe, driven by white dwarf supernova, that we still observe today 
D)  The sudden release of photons when particles and antiparticles annihilate each other 
E)  The photons released when electrons and protons first combined, forming the Cosmic Microwave Background Radiation 
A)  The expansion of universe starting with the instant after the Big Bang 
B)  A sudden expansion of the universe driven by the energy released when the strong and electroweak forces froze out from the GUT force 
C)  The rapid expansion of the universe, driven by white dwarf supernova, that we still observe today 
D)  The sudden release of photons when particles and antiparticles annihilate each other 
E)  The photons released when electrons and protons first combined, forming the Cosmic Microwave Background Radiation

Question 6

Rank these times based on the wavelength of the peak intensity of the cosmic background radiation at those times, from shortest to longest. (Hint: consider how the temperature of the universe or the cosmic background radiation changed with time.)

Accepted Answer

A)  Today, 1 million years after the Big Bang, 100 million years after the Big Bang 
B)  Today, 100 million years after the Big Bang, 1 million years after the Big Bang 
C)  1 million years after the Big Bang, 100 million years after the Big Bang, today 
D)  100 million years after the Big Bang, 1 million years after the Big Bang, today 
A)  Today, 1 million years after the Big Bang, 100 million years after the Big Bang 
B)  Today, 100 million years after the Big Bang, 1 million years after the Big Bang 
C)  1 million years after the Big Bang, 100 million years after the Big Bang, today 
D)  100 million years after the Big Bang, 1 million years after the Big Bang, today

Question 7

Olbers' paradox is an apparently simple question, but its resolution suggests that the universe is finite in age. What is the question?

Accepted Answer

A)  Why is the sky dark at night? 
B)  What would it be like to ride on a beam of light? 
C)  How many stars are in the universe? 
D)  Can we measure the position and momentum of an electron at the same time? 
A)  Why is the sky dark at night? 
B)  What would it be like to ride on a beam of light? 
C)  How many stars are in the universe? 
D)  Can we measure the position and momentum of an electron at the same time?

Question 8

Why weren't many elements heavier than helium produced during the nucleosynthesis era?

Accepted Answer

By the time helium nuclei could exist in

Question 9

Olbers' paradox is an apparently simple question, but its resolution suggests that the universe is finite in age. What is the simple question posed by Olbers' paradox?

Accepted Answer

A)  What would it be like to ride on a beam of light? 
B)  Can we measure the position and momentum of an electron at the same time? 
C)  How does the Sun produce energy? 
D)  Why is the sky dark at night? 
E)  How many stars are in the universe? 
A)  What would it be like to ride on a beam of light? 
B)  Can we measure the position and momentum of an electron at the same time? 
C)  How does the Sun produce energy? 
D)  Why is the sky dark at night? 
E)  How many stars are in the universe?

Question 10

Consider the graph of expansion models. Which model(s) predicts that galaxies will eventually get closer together?

Accepted Answer

A)  Accelerating 
B)  Coasting 
C)  Critical 
D)  Recollapsing 
E)  All of them. F) None of them. 
A)  Accelerating 
B)  Coasting 
C)  Critical 
D)  Recollapsing 
E)  All of them. F) None of them.

Question 11

Which forces have physicists shown to be the same force under conditions of very high temperature, as confirmed by experiments in particle accelerators?

Accepted Answer

A)  gravity and the weak force 
B)  gravity and the strong force 
C)  the strong and weak forces 
D)  the strong and electromagnetic forces 
E)  the electromagnetic and weak forces 
A)  gravity and the weak force 
B)  gravity and the strong force 
C)  the strong and weak forces 
D)  the strong and electromagnetic forces 
E)  the electromagnetic and weak forces

Question 12

Why do we think tiny quantum ripples should have been present in the very early universe?

Accepted Answer

A)  The shock wave of the Big Bang caused ripples that expanded outward with time. 
B)  The energy released when the strong force froze out of the GUT force caused shock waves that produced ripples in the universe. 
C)  The principle of quantum mechanics require that matter and antimatter particles formed from high-energy photons continuously eject energy into the universe causing the ripples. 
D)  The annihilation of matter and antimatter particles caused tiny explosions that produced ripples in the radiation field. 
E)  The principles of quantum mechanics require that the energy fields at any point in space be continually fluctuating. 
A)  The shock wave of the Big Bang caused ripples that expanded outward with time. 
B)  The energy released when the strong force froze out of the GUT force caused shock waves that produced ripples in the universe. 
C)  The principle of quantum mechanics require that matter and antimatter particles formed from high-energy photons continuously eject energy into the universe causing the ripples. 
D)  The annihilation of matter and antimatter particles caused tiny explosions that produced ripples in the radiation field. 
E)  The principles of quantum mechanics require that the energy fields at any point in space be continually fluctuating.

Question 13

Which of the following statements best explains what we mean when we say that the electroweak and strong forces "froze out" at 10⁻³⁸ second after the Big Bang?

Accepted Answer

A)  These two forces first became distinct at this time. 
B)  These forces are important only at temperatures below the freezing point of water-a temperature that the universe reached at an age of about at 10⁻³⁸ second. 
C)  Freezing out was a term coined by particle physicists who think that the Big Bang theory is really cool. 
D)  Following this time, neither the strong nor electroweak forces were ever important in the universe again. 
A)  These two forces first became distinct at this time. 
B)  These forces are important only at temperatures below the freezing point of water-a temperature that the universe reached at an age of about at 10⁻³⁸ second. 
C)  Freezing out was a term coined by particle physicists who think that the Big Bang theory is really cool. 
D)  Following this time, neither the strong nor electroweak forces were ever important in the universe again.

Question 14

Briefly describe the two key pieces of evidence that support the Big Bang theory.

Accepted Answer

The two key pieces of evidence that supp

Question 15

Which statement about the cosmic microwave background is not true?

Accepted Answer

A)  It is the result of a mixture of radiation from many independent sources, such as stars and galaxies. 
B)  Its spectrum corresponds to a temperature of just under 3 degrees above absolute zero. 
C)  With the exception of very small variations, it appears essentially the same in all directions in which we look into space. 
D)  It is thought to be radiation that began its journey to our telescopes when the universe was about 380,000 years old. 
A)  It is the result of a mixture of radiation from many independent sources, such as stars and galaxies. 
B)  Its spectrum corresponds to a temperature of just under 3 degrees above absolute zero. 
C)  With the exception of very small variations, it appears essentially the same in all directions in which we look into space. 
D)  It is thought to be radiation that began its journey to our telescopes when the universe was about 380,000 years old.

Question 16

Comparing the following 4 models, which model predicts that galaxies had the largest separations in the past? (Use the graph of expansion models as a guide.)

Accepted Answer

A)  Accelerating 
B)  Coasting 
C)  Critical 
D)  Recollapsing 
A)  Accelerating 
B)  Coasting 
C)  Critical 
D)  Recollapsing

Question 17

Which of the following statements about the cosmic background radiation is not true?

Accepted Answer

A)  It has a temperature of about 3 degrees K above absolute zero. 
B)  It is the result of a mixture of radiation from many independent sources, such as stars and galaxies that formed within the first billion years of the Big Bang. 
C)  It had a much higher temperature in the past. 
D)  It was discovered by Penzias and Wilson in the mid 1960s. 
E)  It appears essentially the same in all directions (it is isotropic). 
A)  It has a temperature of about 3 degrees K above absolute zero. 
B)  It is the result of a mixture of radiation from many independent sources, such as stars and galaxies that formed within the first billion years of the Big Bang. 
C)  It had a much higher temperature in the past. 
D)  It was discovered by Penzias and Wilson in the mid 1960s. 
E)  It appears essentially the same in all directions (it is isotropic).

Question 18

Refer to this scenario for the following questions:
A multi-dimensional being reaches down to Earth and pulls you out of the universe. You are then thrown back into the universe at a place and time of the being's choosing, and you are permitted to leave only after you have identified your surroundings. This process is repeated several times. Through a scientifically unexplainable miracle, you are able to survive in every one of the places that you find yourself. In each scenario below, identify your surroundings (and potentially your cosmic era) from among the choices given.
-You are in a place that is extremely hot and dense. You can't see far because your surroundings are opaque to light. Around you, nuclear fusion is converting carbon into oxygen and other elements. Where are you?

Accepted Answer

A)  You are in the center of a star very much like our Sun. 
B)  You are in the early universe during the era of nucleosynthesis. 
C)  You are inside a nuclear power plant on Earth. 
D)  You are in the center of a massive star near the end of its life. 
E)  You are in the center of a white dwarf. 
A)  You are in the center of a star very much like our Sun. 
B)  You are in the early universe during the era of nucleosynthesis. 
C)  You are inside a nuclear power plant on Earth. 
D)  You are in the center of a massive star near the end of its life. 
E)  You are in the center of a white dwarf.

Question 19

We have direct experimental evidence (from large particle accelerators) for the physical conditions in the universe back to about ________ after the Big Bang.

Accepted Answer

A)  1 million years 
B)  380,000 years 
C)  300 years 
D)  3 minutes 
E)  10⁻¹⁰ seconds 
A)  1 million years 
B)  380,000 years 
C)  300 years 
D)  3 minutes 
E)  10⁻¹⁰ seconds

Question 20

The idea of inflation makes one clear prediction that, until the discovery of an accelerating expansion, seemed to contradict the available observations. What is this prediction?

Accepted Answer

A)  The universe should be geometrically "flat" (in the four dimensions of spacetime). 
B)  Inflation predicts that the early universe should have regions of enhanced density that could have acted as "seeds" for the formation of galaxies and large structures. 
C)  Inflation predicts that the temperature of the cosmic microwave background should be almost (but not exactly) the same everywhere. 
D)  Inflation predicts that the entire universe must be far larger than the observable universe. 
A)  The universe should be geometrically "flat" (in the four dimensions of spacetime). 
B)  Inflation predicts that the early universe should have regions of enhanced density that could have acted as "seeds" for the formation of galaxies and large structures. 
C)  Inflation predicts that the temperature of the cosmic microwave background should be almost (but not exactly) the same everywhere. 
D)  Inflation predicts that the entire universe must be far larger than the observable universe.

Why does the Big Bang theory predict that the cosmic background radiation should have a perfect thermal radiation spectrum?

Which adjective does not necessarily describe a known feature of the early universe? (Be sure to consider the universe as a whole, not just the observable universe.)

GUT theories predict that protons will eventually decay, causing all solid objects in the universe to fall apart if the universe keeps expanding forever.

What do we mean by inflation?

Rank these times based on the wavelength of the peak intensity of the cosmic background radiation at those times, from shortest to longest. (Hint: consider how the temperature of the universe or the cosmic background radiation changed with time.)

Olbers' paradox is an apparently simple question, but its resolution suggests that the universe is finite in age. What is the question?

Why weren't many elements heavier than helium produced during the nucleosynthesis era?

Olbers' paradox is an apparently simple question, but its resolution suggests that the universe is finite in age. What is the simple question posed by Olbers' paradox?

Consider the graph of expansion models. Which model(s) predicts that galaxies will eventually get closer together?

Which forces have physicists shown to be the same force under conditions of very high temperature, as confirmed by experiments in particle accelerators?

Why do we think tiny quantum ripples should have been present in the very early universe?

Which of the following statements best explains what we mean when we say that the electroweak and strong forces "froze out" at 10⁻³⁸ second after the Big Bang?

Briefly describe the two key pieces of evidence that support the Big Bang theory.

Which statement about the cosmic microwave background is not true?

Comparing the following 4 models, which model predicts that galaxies had the largest separations in the past? (Use the graph of expansion models as a guide.)

Which of the following statements about the cosmic background radiation is not true?

We have direct experimental evidence (from large particle accelerators) for the physical conditions in the universe back to about ________ after the Big Bang.

The idea of inflation makes one clear prediction that, until the discovery of an accelerating expansion, seemed to contradict the available observations. What is this prediction?

Our Place in the Universe

Discovering the Universe for Yourself

The Science of Astronomy

Making Sense of the Universe: Understanding Motion, Energy, and Gravity

Light: the Cosmic Messenger

Formation of Planetary Systems: Our Solar System and Beyond

Earth and the Terrestrial Worlds

Jovian Planet Systems

Asteroids, Comets, and Dwarf Planets: Their Nature, Orbits, and Impacts

Our Star

Surveying the Stars

Star Stuff

Bizarre Stellar Graveyard

Our Galaxy

Galaxies and the Foundation of Modern Cosmology

Dark Matter, Dark Energy, and the Fate of the Universe

Life in the Universe

Filters

Exam 17: The Beginning of Time

Why does the Big Bang theory predict that the cosmic background radiation should have a perfect thermal radiation spectrum?

Which adjective does not necessarily describe a known feature of the early universe? (Be sure to consider the universe as a whole, not just the observable universe.)

GUT theories predict that protons will eventually decay, causing all solid objects in the universe to fall apart if the universe keeps expanding forever.

What do we mean by inflation?

Rank these times based on the wavelength of the peak intensity of the cosmic background radiation at those times, from shortest to longest. (Hint: consider how the temperature of the universe or the cosmic background radiation changed with time.)

Olbers' paradox is an apparently simple question, but its resolution suggests that the universe is finite in age. What is the question?

Why weren't many elements heavier than helium produced during the nucleosynthesis era?

Olbers' paradox is an apparently simple question, but its resolution suggests that the universe is finite in age. What is the simple question posed by Olbers' paradox?

Consider the graph of expansion models. Which model(s) predicts that galaxies will eventually get closer together?

Which forces have physicists shown to be the same force under conditions of very high temperature, as confirmed by experiments in particle accelerators?

Why do we think tiny quantum ripples should have been present in the very early universe?

Which of the following statements best explains what we mean when we say that the electroweak and strong forces "froze out" at 10⁻³⁸ second after the Big Bang?

Briefly describe the two key pieces of evidence that support the Big Bang theory.

Which statement about the cosmic microwave background is not true?

Comparing the following 4 models, which model predicts that galaxies had the largest separations in the past? (Use the graph of expansion models as a guide.)

Which of the following statements about the cosmic background radiation is not true?

We have direct experimental evidence (from large particle accelerators) for the physical conditions in the universe back to about ________ after the Big Bang.

The idea of inflation makes one clear prediction that, until the discovery of an accelerating expansion, seemed to contradict the available observations. What is this prediction?

Our Place in the Universe

Discovering the Universe for Yourself

The Science of Astronomy

Making Sense of the Universe: Understanding Motion, Energy, and Gravity

Light: the Cosmic Messenger

Formation of Planetary Systems: Our Solar System and Beyond

Earth and the Terrestrial Worlds

Jovian Planet Systems

Asteroids, Comets, and Dwarf Planets: Their Nature, Orbits, and Impacts

Our Star

Surveying the Stars

Star Stuff

Bizarre Stellar Graveyard

Our Galaxy

Galaxies and the Foundation of Modern Cosmology

Dark Matter, Dark Energy, and the Fate of the Universe

Life in the Universe

Filters