Chapter 27

In pair production in the Big Bang, which statement is FALSE? Select one: A. Matter is frozen energy, according to Einstein's E = mc2. B. In addition to familiar neutrons and protons, many other exotic particle and antiparticle pairs formed, but decayed back to radiation. C. Every electron should have a proton formed at the same time with it. D. The heaviest particles and their antiparticles formed first, from collisions of the highest energy gamma rays. E. Even neutrons have their antineutrons, although both lack any charge.

Every electron should have a proton formed at the same time with it.

At decoupling, the electrons and protons were made from neutron decay. Select one: True Incorrect False

False

Decoupling refers to interactions between matter and antimatter at the end of the Radiation Era. Select one: True False

False

Deuterium and helium could be made only during the nuclear epoch. Select one: True False

False

In GUTs, the electromagnetic force and weak nuclear force were the first to separate; then came gravity. Select one: True False

False

Pair production is how a proton and electron are formed together from two photons, with neutrinos also given off. Select one: True False

False

Primordial nucleosynthesis refers to the Big Bang making all elements up to iron. Select one: True False

False

Quarks are made up of subatomic particles, such as protons and electrons. Select one: True False

False

The collision of two gamma rays can result in a single particle. Select one: True False

False

The protons, neutrons, and electrons of our atoms were made in the quark epoch. Select one: True False

False

How hot was the universe at time zero? Select one: A. 1032 K B. 2.73 K C. 5, 800 K D. 16, 000 K E. We have no theory capable to addressing this question.

We have no theory capable to addressing this question.

Why didn't elements heavier than helium form in the first minutes of creation? Select one: A. The electrons slowed down enough to be captured into orbits by protons. B. When He-4 was formed, the expansion cooled the cosmos below 100 million K. C. Only type I supernovae can produce iron and heavier elements. D. The first generation of stars used them up too quickly to observe them. E. There was not enough matter in the universe at that time.

When He-4 was formed, the expansion cooled the cosmos below 100 million K.

The redshift of the universe at decoupling was about: Select one: A. Z = 10. B. Z = 1,100. C. Z = 1,000,000. D. Z = 4. E. Z = 400,000.

Z = 1,100.

How do astronomers define the "superforce"? Select one: A. the GUT, with all five forces combined B. a force including only dark energy and gravity C. the GUT, but with no dark energy added in D. a force connecting gravity and the electroweak force E. a force connecting electromagnetism with the strong and the weak nuclear forces

a force connecting electromagnetism with the strong and the weak nuclear forces

What would help scientists probe the period from zero time to 10-43 second? Select one: A. more detailed observations of the cosmic microwave background B. a better understanding of the nature of dark energy C. a theory incorporating the force of gravity into existing GUTs D. discovery of a white hole, with matter and energy flowing out E. more sophisticated gravity wave detectors

a theory incorporating the force of gravity into existing GUTs

Before the Planck time of 10-43 seconds, the Big Bang must be treated as a singularity, with even general relativity yielding no information about it. Select one: True False

True

Deuterium was made only in primordial nucleosynthesis, since stars destroy it. Select one: True False

True

In GUTs, gravity was the first force to take on a separate identity at the Planck Time. Select one: True False

True

In pair production, the heaviest particles are formed in reactions that have the highest temperatures. Select one: True False

True

Including all energy and mass, both dark and traditional, we seem to live now in a matter dominated universe, since the observed matter density exceeds the observed energy density. Select one: True False

True

Not taking dark energy into account, we seem to live now in a matter dominated universe, since the observed matter density exceeds the observed energy density. Select one: True False

True

Physicists have detected hot dark matter particles in terrestrial laboratories, but it is much harder to observe than cold dark matter. Select one: True False

True

Sound waves in the early universe traveled faster than half of the speed of light. Select one: True False

True

String theories, like GUTs, explain how gravity was combined with the other fundamental forces in the very early universe. Select one: True False

True

The density of the cosmos at the end of the lepton epoch was comparable to iron, about ten times denser than water. Select one: True False

True

The flatness problem is the fact that the observed density of matter is unexpectedly different from the critical density predicted by the inflationary epoch. Select one: True False

True

The horizon problem relates to the isotropy of the microwave background radiation. Select one: True False

True

The majority of dark matter is probably not protons and neutrons. Select one: True False

True

The period before the separation of the gravitational force is the Planck Epoch. Select one: True False

True

The universe expanded by a factor of 1050 during inflation, when the strong force separated from the electromagnetic and weak nuclear forces. Select one: True False

True

When an electron is formed from a gamma-ray collision, a positron is also made. Select one: True False

True

In the Grand Unified Theory, the superforce was: Select one: A. only dark energy. B. a union of the gravitational, strong and weak nuclear, and electromagnetic forces. C. only in effect at low energies. D. a union of all matter and energy. E. a union of the weak and electromagnetic forces.

a union of the gravitational, strong and weak nuclear, and electromagnetic forces.

The crossover point from radiation to matter domination occurred: Select one: A. with the creation of electrons and positrons at about 6 × 109 K. B. about 50,000 years after the Big Bang, at a temperature of about 16,000 K. C. with the emission of the cosmic background radiation. D. with the creation of neutrons and protons, at about 1013 K. E. when the strong force separated from the other two forces.

about 50,000 years after the Big Bang, at a temperature of about 16,000 K.

The stellar epoch, which we are still in today, began: Select one: A. about 100 million years after the Big Bang, with the making of galaxies. B. with the liberation of the dark energy. Incorrect C. with the end of the lepton epoch, when neutrinos were formed and escaped from matter. D. with the end of the quark epoch, when neutrons and protons fused into deuterium. E. about three billion years after the Big Bang, with Population I stars forming.

about three billion years after the Big Bang, with Population I stars forming.

At what point do the weak nuclear and electromagnetic forces split? Select one: A. at 1012 K, when pair production starts for neutrons and protons B. at 10-43 seconds, when all four forces separate as the Planck Era ends C. never, they are still united D. after about 10-10 seconds, when the temperature drops below 10-15 K E. at about four seconds, when at millions of degrees hydrogen forms helium

after about 10-10 seconds, when the temperature drops below 10-15 K

Both protons and neutrons (and their anti-particles) froze out: Select one: A. at 1032 K, at the end of the Inflationary Era. B. about 50,000 years after the Big Bang. C. after 10-43 seconds, at the Planck Era. D. at 1013 K, about .0001 seconds after the Big Bang. E. after about a minute of expansion.

at 1013 K, about .0001 seconds after the Big Bang.

During the nuclear epoch, the temperatures were: Select one: A. higher than 1032 K. B. less than 10 million K. C. about a trillion degrees. D. between 3,000 and 16,000 K. E. comparable to the temperatures inside giant stars today.

comparable to the temperatures inside giant stars today.

At this time, the universe is: Select one: A. radiation dominated. B. quark dominated. C. lepton dominated. D. matter dominated. E. dark energy dominated.

dark energy dominated.

Currently, most of the mass of the matter of the universe is believed to consist of: Select one: A. tachyonic matter, travelling only faster than the speed of light. B. tiny but very numerous black holes. C. baryonic matter, made up of protons and neutrons. D. dark matter not made of protons and neutrons. E. dark energy.

dark matter not made of protons and neutrons.

The scarcity of what isotope is a critical test of the density of the present cosmos? Select one: A. deuterium B. lithium 5 C. carbon 14 D. helium 3 E. helium 4

deuterium

Which of these substances must be primordial? Select one: A. beryllium B. helium C. lithium D. tritium E. deuterium

deuterium

The nuclear epoch occurred during the formation of: Select one: A. all elements up to iron. B. all known elements. C. only protons and neutrons. D. deuterium and helium. E. dark energy.

deuterium and helium.

The critical temperature for nucleosynthesis to begin was the: Select one: A. formation of lithium at 50 million K. B. proton-proton cycle at 10 million K. C. deuterium bottleneck at about 900 million K. D. iron production at 10 billion K. E. triple alpha reaction at 100 million K.

deuterium bottleneck at about 900 million K.

In the process of pair production, which of the following is a possible product pair? Select one: A. electron-positron B. proton-positron C. electron-proton D. electron-neutron E. proton-neutron

electron-positron

Gravity becomes separate from the other forces at the: Select one: A. beginning of particle production, about .0001 seconds into the universe. B. end of the Planck Era, about 10-43 seconds after the Big Bang. C. end of the Inflationary Epoch, about 10-32 seconds into creation. D. end of electron production, about a minute after creation. E. decoupling Event, about a million years after the Big Bang.

end of the Planck Era, about 10-43 seconds after the Big Bang.

The "flatness" problem arises because the curvature of space seems remarkably close to: Select one: A. zero curvature, favoring a spherical cosmos. B. 2.73 K, in spite of the eddies and turbulence that led to galaxy formation. C. infinity, suggesting an open universe is the only possible cosmology. D. .5, suggesting we are split between open and closed universes. E. exactly one.

exactly one.

Ripples in the Cosmic Microwave Background correspond to: Select one: A. matter density fluctuations. B. temperature fluctuations. C. imperfections in measurement techniques or equipment. D. energy fluctuations. E. fluctuations in both matter and radiation.

fluctuations in both matter and radiation.

The Big Bang formed: Select one: A. all elements up to iron. B. only helium. C. only hydrogen. D. hydrogen and helium, but nothing else. E. all elements found in nature now.

hydrogen and helium, but nothing else.

Of the normal elements around us, the Big Bang produced: Select one: A. all elements in much their present proportions. B. hydrogen and helium. C. all elements up to iron. D. only hydrogen. E. none, only energy.

hydrogen and helium.

Concerning dark energy, we do know: Select one: A. combined with dark matter, it will ultimately produce a closed universe. B. its density remains constant over time, so it is not important in the early Universe. C. that it makes up 90% of all the matter and energy in the whole universe. D. that it was revealed with Type II supernovae distances in the late 1990s. E. that it is created when matter annihilates anti-matter.

its density remains constant over time, so it is not important in the early Universe

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

large-scale filaments containing both normal matter and dark matter.

The period from about one to 100 seconds after the Big Bang is called the: Select one: A. lepton epoch. B. quark epoch. C. nuclear epoch. D. atomic epoch. E. pair-production era.

lepton epoch.

Collectively, electrons, muons, and neutrinos are called: Select one: A. baryons. B. hadrons. C. photons. D. pions. E. leptons.

leptons.

Because of their mass, the threshold temperature for electrons is: Select one: A. lower than that of hydrogen. B. lower than that of protons. C. higher than that of hydrogen. D. higher than that of neutrons. E. higher than that of protons.

lower than that of protons.

Before about 4 billion years ago the universe was: Select one: A. radiation dominated. B. quark dominated. C. lepton dominated. D. matter dominated. E. dark energy dominated.

matter dominated.

Which of these could be considered as "hot dark matter"? Select one: A. dark energy B. weakly interacting magnetic particles (WIMPS) C. neutrinos D. deuterium E. dust close to H II regions

neutrinos

Which of these orderings of the epochs is correct? Select one: A. atomic, nuclear, stellar B. nuclear, quark, galactic C. nuclear, lepton, quark D. galactic, stellar, atomic E. Planck, lepton, quark

nuclear, quark, galactic

When new particle pairs are being created as fast as they annihilate, it is: Select one: A. the critical density. B. hydrostatic equilibrium. C. thermal equilibrium. D. the cosmological constant. E. the threshold equilibrium.

thermal equilibrium.

The critical temperature above which pair production can occur is called the: Select one: A. fusion temperature. B. event horizon. C. Chandrasekhar Limit. D. Cosmological Constant. E. threshold temperature.

threshold temperature.

Oscillations in the early universe are most similar to: Select one: A. water waves. B. light waves. Incorrect C. seismic waves. D. sound waves. E. oscillations of stars in the instability strip of the H-R diagram.

water waves.

About how hot was the Big Bang when matter and energy "decoupled"? Select one: A. 15 million K B. 3,000 K C. 2.73 K D. 300 K E. 900 million K

3,000 K

At the end of the first fifteen minutes, the mass ratio of H/He created was about: Select one: A. 27/73. B. 50/50. C. 90/10. D. 1/4. E. 75/25.

75/25.

How does the energy of the cosmic microwave background compare to the energy radiated by all the stars and galaxies that ever existed? Select one: A. They are very close to being equal. B. About ten times more from the Big Bang than from stars and galaxies. C. The starlight now dominates the background, as your eyes show clearly. D. 73% cosmic background, 27% starlight. E. We have no way of comparing matter and energy this way.

About ten times more from the Big Bang than from stars and galaxies.

Which of these did NOT occur at decoupling? Select one: A. Neutral atoms were formed. B. The universe became transparent. C. Electrons began to orbit protons. D. The cosmic microwave radiation was released from matter. E. Matter dominated radiation.

Matter dominated radiation.

The period from about 100 seconds up to 15 minutes after the Big Bang is the: Select one: A. Radiation Era. B. Decoupling Epoch. C. Matter Era. D. Nuclear Epoch. E. Lepton Epoch.

Nuclear Epoch.

What key event took place during the atomic epoch? Select one: A. Atoms in the universe collected to form stars and galaxies. B. The universe expanded and cooled enough to allow the first particles to appear. C. The neutrinos were created. D. The universe underwent a brief period of rapid expansion. E. The universe expanded and cooled enough for electrons to orbit protons.

The universe expanded and cooled enough for electrons to orbit protons.

The quark epoch is when ________ was/were created. Select one: A. everything in normal atoms B. protons and neutrons that still survive C. all known matter D. the rapid inflation of the cosmos E. only dark energy

protons and neutrons that still survive

Which of these orderings of the epochs is correct? Select one: A. nuclear, lepton, quark B. quark, lepton, atomic C. nuclear, stellar, galactic D. Planck, lepton, quark E. Planck, stellar, galactic

quark, lepton, atomic

Most of the deuterium that formed right after the Big Bang: Select one: A. quickly burned into helium nuclei. B. broke down into electrons and neutrons. C. is still around today. D. was found in the globular clusters. E. turned into dark matter.

quickly burned into helium nuclei.

Before about 50,000 years after the Big Bang, the universe was: Select one: A. radiation dominated. B. quark dominated. C. lepton dominated. D. matter dominated. E. dark energy dominated.

radiation dominated.

Observed temperature fluctuations in the Cosmic Microwave Background Radiation are: Select one: A. hundreds of kelvins. B. immeasurably small. C. millions of kelvins. D. a few kelvins. E. tens of millionths of a kelvin.

tens of millionths of a kelvin.

There is observational evidence that supports the theoretical conditions of the universe. The farthest back in the history of the universe this evidence goes is: Select one: A. the beginning of GUT. B. the end of the Planck epoch. C. the end of the Radiation Era. D. the moment of the Big Bang. E. the Recombination Epoch.

the Recombination Epoch.

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

the Universe was opaque to radiation

Scientists are able to use the theories of physics to describe the conditions of the universe back to: Select one: A. the end of the Radiation Era. B. the end of the Planck Epoch. C. the Recombination Epoch. D. the moment of the Big Bang. E. the beginning of GUT.

the end of the Planck Epoch.

Pair production can occur if: Select one: A. the particle and antiparticle have opposite spins. B. one particle is struck by a sufficiently high energy photon that a pair of electrons is formed. C. photons are at the event horizon of a black hole. D. the energy of two photons is greater than the combined mass-energy of a particle-antiparticle pair. E. only virtual particles are produced.

the energy of two photons is greater than the combined mass-energy of a particle-antiparticle pair.

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

the galactic epoch, when the main events were galaxy construction.

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

the horizon problem, in that the microwave background is almost too isotropic

Which of these seems the best present answer to the horizon and flatness problems? Select one: A. symmetry in creation of particles and antiparticles B. Dark Energy speeds the universe on out to infinity. C. the inflationary epoch D. The superforce rules creation. E. the GUT theory

the inflationary epoch

The best answer to both the flatness and horizon problems is: Select one: A. dark energy. B. the Steady State Theory. C. the inflationary epoch. D. decoupling. E. the GUT theory.

the inflationary epoch.

The one theory of the early universe before the Recombination Epoch and after the Planck Epoch that was developed to resolve a conflict between observation and theory is: Select one: A. the theory of inflation. B. the theory of recombination. C. the Grand Unified Theory. D. the quantum quark theory. E. the theory of nucleosynthesis.

the theory of inflation.