Question 1

Cold-dark-matter models predict:

Accepted Answer

A) large-scale filaments containing both normal matter and dark matter. 
B) no structure on a smaller scale than superclusters. 
C) the universe is less than 10 billion years old. 
D) dense regions of the early universe that led to galaxies formed after decoupling. 
E) that dark matter is the largest component of the universe's density. 
A) large-scale filaments containing both normal matter and dark matter. 
B) no structure on a smaller scale than superclusters. 
C) the universe is less than 10 billion years old. 
D) dense regions of the early universe that led to galaxies formed after decoupling. 
E) that dark matter is the largest component of the universe's density.

Question 2

How do astronomers define the "superforce"?

Accepted Answer

A) a force connecting electromagnetism with the strong and the weak nuclear forces 
B) the GUT, with all five forces combined 
C) the GUT, but with no dark energy added in 
D) a force connecting gravity and the electroweak force 
E) a force including only dark energy and gravity 
A) a force connecting electromagnetism with the strong and the weak nuclear forces 
B) the GUT, with all five forces combined 
C) the GUT, but with no dark energy added in 
D) a force connecting gravity and the electroweak force 
E) a force including only dark energy and gravity

Question 3

At decoupling, the electrons and protons were made from neutron decay.

Accepted Answer

A) True 
 B)False

Question 4

At this time, the universe is:

Accepted Answer

A) radiation dominated. 
B) quark dominated. 
C) lepton dominated. 
D) matter dominated. 
E) dark energy dominated. 
A) radiation dominated. 
B) quark dominated. 
C) lepton dominated. 
D) matter dominated. 
E) dark energy dominated.

Question 5

The crossover point from radiation to matter domination occurred:

Accepted Answer

A) when the strong force separated from the other two forces. 
B) with the emission of the cosmic background radiation. 
C) about 50,000 years after the Big Bang, at a temperature of about $16,000 \mathrm {~K}.$ 
D) with the creation of neutrons and protons, at about $10^{13} \mathrm {~K}$ 
E) with the creation of electrons and positrons at about $6 \times 10 ^ { 9 } \mathrm {~K}$ 
A) when the strong force separated from the other two forces. 
B) with the emission of the cosmic background radiation. 
C) about 50,000 years after the Big Bang, at a temperature of about $16,000 \mathrm {~K}.$ 
D) with the creation of neutrons and protons, at about $10^{13} \mathrm {~K}$ 
E) with the creation of electrons and positrons at about $6 \times 10 ^ { 9 } \mathrm {~K}$

Question 6

How does the energy of the cosmic microwave background compare to the energy radiated byall the stars and galaxies that ever existed?

Accepted Answer

A) They are very close to being equal. 
B) 73% cosmic background, 27% starlight. 
C) About ten times more from the Big Bang than from stars and galaxies. 
D) The starlight now dominates the background, as your eyes show clearly. 
E) We have no way of comparing matter and energy this way. 
A) They are very close to being equal. 
B) 73% cosmic background, 27% starlight. 
C) About ten times more from the Big Bang than from stars and galaxies. 
D) The starlight now dominates the background, as your eyes show clearly. 
E) We have no way of comparing matter and energy this way.

Question 7

Because of their mass, the threshold temperature for electrons is:

Accepted Answer

A) higher than that of neutrons. 
B) lower than that of protons. 
C) higher than that of protons. 
D) lower than that of hydrogen. 
E) higher than that of hydrogen. 
A) higher than that of neutrons. 
B) lower than that of protons. 
C) higher than that of protons. 
D) lower than that of hydrogen. 
E) higher than that of hydrogen.

Question 8

Before the decoupling:

Accepted Answer

A) the Universe was transparent to radiation. 
B) the Universe was opaque to radiation. 
C) protons and electrons combined to form atoms. 
D) there was more helium than hydrogen. 
E) deuterium produced electrons and positrons. 
A) the Universe was transparent to radiation. 
B) the Universe was opaque to radiation. 
C) protons and electrons combined to form atoms. 
D) there was more helium than hydrogen. 
E) deuterium produced electrons and positrons.

Question 9

Why were elements heavier than helium not produced during the Big Bang?

Accepted Answer

Once helium was formed from de

Question 10

Deuterium and helium could be made only during the nuclear epoch.

Accepted Answer

A) True 
 B)False

Question 11

Describe the conditions of matter and radiation when in a state of thermal equilibrium.

Accepted Answer

In thermal equilibrium, matter

Question 12

Sound waves in the early universe are more technically known as ________.

Accepted Answer

baryon aco

Question 13

After the atomic epoch, and before the current stellar epoch, came:

Accepted Answer

A) the black hole epoch, when black holes were common. 
B) the end of the lepton epoch, when neutrinos were formed and escaped from matter. 
C) the liberation of the dark energy. 
D) the galactic epoch, when the main events were galaxy construction. 
E) about three billion years after the Big Bang, with Population I stars forming. 
A) the black hole epoch, when black holes were common. 
B) the end of the lepton epoch, when neutrinos were formed and escaped from matter. 
C) the liberation of the dark energy. 
D) the galactic epoch, when the main events were galaxy construction. 
E) about three billion years after the Big Bang, with Population I stars forming.

Question 14

The best answer to both the flatness and horizon problems is:

Accepted Answer

A) the Steady State Theory. 
B) the GUT theory. 
C) the inflationary epoch. 
D) dark energy. 
E) decoupling. 
A) the Steady State Theory. 
B) the GUT theory. 
C) the inflationary epoch. 
D) dark energy. 
E) decoupling.

Question 15

The nuclear epoch occurred during the formation of:

Accepted Answer

A) only protons and neutrons. 
B) dark energy. 
C) deuterium and helium. 
D) all elements up to iron. 
E) all known elements. 
A) only protons and neutrons. 
B) dark energy. 
C) deuterium and helium. 
D) all elements up to iron. 
E) all known elements.

Question 16

In the process of pair production, which of the following is a possible product pair?

Accepted Answer

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

Question 17

Which of these could be considered as "hot dark matter"?

Accepted Answer

A) deuterium 
B) weakly interacting magnetic particles (WIMPS) 
C) neutrinos 
D) dust close to H II regions 
E) dark energy 
A) deuterium 
B) weakly interacting magnetic particles (WIMPS) 
C) neutrinos 
D) dust close to H II regions 
E) dark energy

Question 18

What are the important relics of the quark epoch? Why?

Accepted Answer

Quarks condensed to form massi

Question 19

In the Grand Unified Theory, the superforce was:

Accepted Answer

A) only dark energy. 
B) a union of the weak and electromagnetic forces. 
C) a union of all matter and energy. 
D) a union of the gravitational, strong and weak nuclear, and electromagnetic forces. 
E) only in effect at low energies. 
A) only dark energy. 
B) a union of the weak and electromagnetic forces. 
C) a union of all matter and energy. 
D) a union of the gravitational, strong and weak nuclear, and electromagnetic forces. 
E) only in effect at low energies.

Question 20

What did the cosmic microwave background tell cosmologists about the early universe?

Accepted Answer

A) Nothing; it is a product of the black hole in the center of our own Galaxy. 
B) the horizon problem, in that the microwave background is almost too isotropic 
C) the discovery of dark energy and its role in accelerating the universe 
D) the discovery of relativistic redshifts and the Big Bang 
E) The dark matter in the universe is mostly baryonic in nature, for a closed Big Bang. 
A) Nothing; it is a product of the black hole in the center of our own Galaxy. 
B) the horizon problem, in that the microwave background is almost too isotropic 
C) the discovery of dark energy and its role in accelerating the universe 
D) the discovery of relativistic redshifts and the Big Bang 
E) The dark matter in the universe is mostly baryonic in nature, for a closed Big Bang.

Exam 27: The Early Universe: Toward the Beginning of Time

Cold-dark-matter models predict:

How do astronomers define the "superforce"?

At decoupling, the electrons and protons were made from neutron decay.

At this time, the universe is:

The crossover point from radiation to matter domination occurred:

How does the energy of the cosmic microwave background compare to the energy radiated byall the stars and galaxies that ever existed?

Because of their mass, the threshold temperature for electrons is:

Before the decoupling:

Why were elements heavier than helium not produced during the Big Bang?

Deuterium and helium could be made only during the nuclear epoch.

Describe the conditions of matter and radiation when in a state of thermal equilibrium.

Sound waves in the early universe are more technically known as ________.

After the atomic epoch, and before the current stellar epoch, came:

The best answer to both the flatness and horizon problems is:

The nuclear epoch occurred during the formation of:

In the process of pair production, which of the following is a possible product pair?

Which of these could be considered as "hot dark matter"?

What are the important relics of the quark epoch? Why?

In the Grand Unified Theory, the superforce was:

What did the cosmic microwave background tell cosmologists about the early universe?

Charting the Heavens: The Foundations of Astronomy

The Copernican Revolution: The Birth of Modern Science

Radiation: Information From the Cosmos

Spectroscopy: the Inner Workings of Atoms

Telescopes: The Tools of Astronomy

The Solar System: Comparative Planetology and Formation Models

Earth: Our Home in Space

The Moon and Mercury: Scorched and Battered Worlds

Venus: Earths Sister Planet

Mars: a Near Miss for Life

Jupiter: Giant of the Solar System

Saturn: Spectacular Rings and Mysterious Moons

Uranus and Neptune: The Outer Worlds of the Solar System

Solar System Debris: Keys to Our Origin

Exoplanets: Planetary Systems Beyond Our Own

The Sun: Our Parent Star

The Stars: Giants, Dwarfs, and the Main Sequence

The Interstellar Medium: Gas and Dust Among the Stars

Star Formation: a Traumatic Birth

Stellar Evolution: The Life and Death of a Star

Stellar Explosions: Novae, Supernovae, and the Formation of the Elements

Neutron Stars and Black Holes: Strange States of Matter

The Milky Way Galaxy: a Spiral in Space

Galaxies: Building Blocks of the Universe

Galaxies and Dark Matter: The Large-Scale Structure of the Cosmos

Cosmology: The Big Bang and the Fate of the Universe

Life in the Universe: Are We Alone

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