Question 1

The Big Bang theory seems to explain how elements were formed during the first few minutes after the Big Bang. Which hypothetical observation below (these are not real observations) would call our current theory into question?

Accepted Answer

A)  The discovery of a galaxy with a helium abundance of only 10% by mass 
B)  The discovery of a star-like object made entirely of carbon and oxygen 
C)  The discovery of a planet that with no helium in its atmosphere 
D)  The discovery of a galaxy with 27% helium rather than the 25% that theory tells us was produced in the Big Bang

Question 2

Why can't current theories describe what happened during the Planck era?

Accepted Answer

A)  We do not yet have a theory that links quantum mechanics and general relativity. 
B)  We do not understand the properties of the antimatter that would have been produced at this time. 
C)  We do not yet have a theory that links the weak and electromagnetic forces. 
D)  We do not yet have a theory that explains how the universe underwent a rapid period of inflationary expansion. 
E)  The Planck era was the time before the Big Bang, and we cannot describe what happened before the beginning of the universe.

Question 3

Why is the night sky is dark?

Accepted Answer

A)  The universe has a physical edge, beyond which there is nothing. 
B)  The dust clouds in interstellar space block the light. 
C)  Dark matter obscures light from distant objects. 
D)  The universe is finite in age.

Question 4

Which of the following histories are in the correct order of occurrence?

Accepted Answer

A)  The Big Bang, then the expansion starts, then stars make the first elements heavier than helium, then the Sun forms. 
B)  The Big Bang happens simultaneously with the start of the expansion of the universe, then stars make the first elements heavier than helium, then the Sun forms. 
C)  The Big Bang happens simultaneously with the start of the expansion of the universe, then the Sun and stars make the first elements heavier than helium. 
D)  The Big Bang, then the expansion starts, then the Sun and stars make the first elements heavier than helium.

Question 5

Why might inflation have occurred at the end of the GUT era?

Accepted Answer

A)  Gravity was an extremely weak force at this period in time. 
B)  Large amounts of matter and antimatter annihilated at this time. 
C)  There wasn't enough matter present to slow down the expansion at that time. 
D)  The universe was too small and needed to grow quickly. 
E)  An enormous amount of energy was released when the strong and electroweak forces froze out from the GUT force.

Question 6

The observed composition of ordinary matter in the universe-roughly 75 percent hydrogen and 25 percent helium-closely matches theoretical predictions based on the Big Bang model.

Accepted Answer

A) True 
 B)False

Question 7

Which event in the history of the universe happened last?

Accepted Answer

A)  The electroweak force separated into electromagnetic and weak nuclear forces. 
B)  Stable helium nuclei formed. 
C)  Neutral atoms formed. 
D)  The GUT force separated into the electroweak force and strong force.

Question 8

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.
-A moment before, you were enveloped in a bright plasma. You could not see very far as free electrons zipped around your head, scattering photons. But now, the universe has suddenly become transparent and you can see clearly. There seem to be no planets or stars, only a gas filled with mostly neutral hydrogen atoms. Where are you?

Accepted Answer

A)  You are in the universe when it was about 500 million years old, just before galaxies began to form. 
B)  You are in the universe about 380,000 year after the Big Bang during the formation of the cosmic background radiation. 
C)  You are in the universe about 5 minutes after the Big Bang just as the nucleosynthesis era is ending. 
D)  You are in a closed universe just as it begins to re-collapse. 
E)  You are in intergalactic space within a rich cluster of galaxies.

Question 9

Laboratory experiments conducted with particle accelerators confirm predictions made by the theory that unifies ________.

Accepted Answer

A)  the electromagnetic and weak forces into the electroweak force 
B)  the strong, weak, and electromagnetic forces into the GUT force 
C)  the unification of all four forces into a single "superforce" 
D)  the strong and weak forces into the combined nuclear force

Question 10

Why is the nucleosynthesis era so important in determining the chemical composition of the universe?

Accepted Answer

A)  All the elements except hydrogen were produced in the nucleosynthesis era. 
B)  We can observe spectra from this era to determine what the primordial mix of the elements was at the beginning of the universe. 
C)  Except for a small amount of elements heavier than helium produced later by stars, the chemical composition of the universe is the same now as at the end of the nucleosynthesis era. 
D)  We can study the processes that occurred during the nucleosynthesis era to determine how most of the elements in the universe were created. 
E)  By knowing how much matter was created during the nucleosynthesis era, we can determine whether the universe is open or closed.

Question 11

Evidence for Inflation: What is the observational evidence the universe underwent a brief but very rapid period of inflation at the end of the GUT era, early in the history of the Universe. Does any of this evidence count as direct observational evidence? Does the validity of the Big Bang depend on inflation being correct?

Accepted Answer

The answer of Evidence for Inflation: What is the observational...

Question 12

Observations of the cosmic background radiation from the COBE satellite revealed tiny variations in its temperature by about 1 part in 100,000.

Accepted Answer

A) True 
 B)False

Question 13

Which of the following statements correctly summarizes the events in the early universe according to the Big Bang theory?

Accepted Answer

A)  The universe began with the forces unified. During the first fraction of a second, the forces separated and there was a brief but important episode of inflation. Subatomic particles of both matter and antimatter then began to appear from the energy present in the universe. Most of the particles annihilated to make photons, but some became protons, neutrons, electrons, and neutrinos. The protons and neutrons underwent some fusion during the first three minutes, thereby determining the basic chemical composition of the universe. 
B)  An episode of what we call inflation initiated the event of the Big Bang. Once the Big Bang got underway, particles and forces began to appear one by one. The forces produced protons, which fused to make hydrogen and helium until the universe was about 380,000 years old. Then gravity began to act, turning the hydrogen and helium into galaxies. 
C)  Forces and various subatomic particles began to appear during the first second after the Big Bang. For reasons not understood, the particles were all made of ordinary matter and none were made of antimatter, thus explaining why we live in a universe made of matter. The particles underwent some fusion for the first 380,000 years after the Big Bang, at which time the first stars were born. 
D)  The Big Bang began with the initiation of what we call inflation, which gradually slowed to the current expansion rate of the universe. Forces came to exist for a different reason, having to do with quantum fluctuations in the space-time continuum. Particles came to exist as a result of cracks made when forces froze. Once there were particles, gravity brought them together to make stars, and the stars then turned the particles into hydrogen, helium, and other elements.

Question 14

In principle, if we could see all the way to the cosmological horizon we could see the Big Bang taking place. However, our view is blocked for times prior to about 380,000 years after the Big Bang. Why?

Accepted Answer

A)  Before that time, the universe was too crowded with stars. 
B)  Before that time, the gas in the universe was dense and ionized and therefore did not allow light to travel freely. 
C)  Before that time, the universe was dark so there was no light to illuminate anything. 
D)  380,000 years after the Big Bang marks the time when stars were first born, and thus began to shine the light by which we can see the universe.

Question 15

Which of the following claims cannot be proved or disproved by science?

Accepted Answer

A)  The universe is about 14 billion years old. 
B)  The universe is about 2000 years old. 
C)  The universe was created by God. 
D)  The universe started out very hot.

Question 16

The Planck era refers to the time period

Accepted Answer

A)  before the Big Bang. 
B)  before the Planck time. 
C)  after the Planck time. 
D)  after inflation. 
E)  after the GUT era.

Question 17

What is the significance of the Planck time?

Accepted Answer

A)  Before it, conditions were so extreme that our current understanding of physics is insufficient to predict what might have occurred. 
B)  It is the time at which inflation is thought to have occurred. 
C)  It is the time when the cosmic microwave background was released. 
D)  It is the amount of time required for two protons to fuse to make deuterium.

Question 18

What is Olbers' paradox, and what is its resolution?

Accepted Answer

The answer of What is Olbers' paradox, and what is...

Question 19

Recent measurements of temperature fluctuations in the cosmic microwave background radiation indicate that 72 percent of the mass-energy in the universe must be in the form of dark energy.

Accepted Answer

A) True 
 B)False

Question 20

Briefly explain how Hubble's discovery of a relationship between galactic distance and redshift led to the idea of the Big Bang.

Accepted Answer

The answer of Briefly explain how Hubble's discovery of a...

Exam 17: The Beginning of Time

The Big Bang theory seems to explain how elements were formed during the first few minutes after the Big Bang. Which hypothetical observation below (these are not real observations) would call our current theory into question?

Why can't current theories describe what happened during the Planck era?

Why is the night sky is dark?

Which of the following histories are in the correct order of occurrence?

Why might inflation have occurred at the end of the GUT era?

The observed composition of ordinary matter in the universe-roughly 75 percent hydrogen and 25 percent helium-closely matches theoretical predictions based on the Big Bang model.

Which event in the history of the universe happened last?

Laboratory experiments conducted with particle accelerators confirm predictions made by the theory that unifies ________.

Why is the nucleosynthesis era so important in determining the chemical composition of the universe?

Observations of the cosmic background radiation from the COBE satellite revealed tiny variations in its temperature by about 1 part in 100,000.

Which of the following statements correctly summarizes the events in the early universe according to the Big Bang theory?

In principle, if we could see all the way to the cosmological horizon we could see the Big Bang taking place. However, our view is blocked for times prior to about 380,000 years after the Big Bang. Why?

Which of the following claims cannot be proved or disproved by science?

The Planck era refers to the time period

What is the significance of the Planck time?

What is Olbers' paradox, and what is its resolution?

Recent measurements of temperature fluctuations in the cosmic microwave background radiation indicate that 72 percent of the mass-energy in the universe must be in the form of dark energy.

Briefly explain how Hubble's discovery of a relationship between galactic distance and redshift led to the idea of the Big Bang.