Question 1

What caused the Big Bang and the expansion of the universe?

Accepted Answer

A)  separation of the strong nuclear force as a distinct force 
B)  decoupling of radiation from matter 
C)  unknown cause, with expansion starting suddenly and continuing to this time 
D)  universal repulsive force stronger than the gravitational attraction between matter in the universe 
A)  separation of the strong nuclear force as a distinct force 
B)  decoupling of radiation from matter 
C)  unknown cause, with expansion starting suddenly and continuing to this time 
D)  universal repulsive force stronger than the gravitational attraction between matter in the universe

Question 2

The very small detected irregularities in the uniformity of the cosmic microwave background are considered to be very important in the study of the evolution of the universe because they

Accepted Answer

A)  show that the Big Bang explosion was very nonuniform. 
B)  were the seeds of supermassive black holes around which the earliest superclusters of galaxies then formed. 
C)  are thought to have led to the development of the present concentrations of matter and energy in superclusters of galaxies. 
D)  are thought to contain most of the elusive "missing matter" in the form of energy concentration in the universe. 
A)  show that the Big Bang explosion was very nonuniform. 
B)  were the seeds of supermassive black holes around which the earliest superclusters of galaxies then formed. 
C)  are thought to have led to the development of the present concentrations of matter and energy in superclusters of galaxies. 
D)  are thought to contain most of the elusive "missing matter" in the form of energy concentration in the universe.

Question 3

The expansion of the universe takes place

Accepted Answer

A)  only between objects separated by vacuum; as a result, human bodies do not expand, but the Earth-Moon system does. 
B)  between all objects, even between the atoms in human bodies, although the expansion of a person is too small to be measured reliably. 
C)  only over distances the size of a galaxy or larger; consequently, the Milky Way Galaxy expands, but the solar system does not. 
D)  primarily in the huge spaces between clusters of galaxies; "small" objects like galaxies or Earth do not expand. 
A)  only between objects separated by vacuum; as a result, human bodies do not expand, but the Earth-Moon system does. 
B)  between all objects, even between the atoms in human bodies, although the expansion of a person is too small to be measured reliably. 
C)  only over distances the size of a galaxy or larger; consequently, the Milky Way Galaxy expands, but the solar system does not. 
D)  primarily in the huge spaces between clusters of galaxies; "small" objects like galaxies or Earth do not expand.

Question 4

During which period in the universe's history did its galaxies undergo the MOST vigorous period of star formation?

Accepted Answer

A)  the first 500 million years after the Big Bang 
B)  from about 500 million to 2.5 million years after the Big Bang 
C)  the past four billion years 
D)  the past billion years 
A)  the first 500 million years after the Big Bang 
B)  from about 500 million to 2.5 million years after the Big Bang 
C)  the past four billion years 
D)  the past billion years

Question 5

What is the isotropy (or horizon) problem?

Accepted Answer

A)  The universe is not as uniform as the standard cosmological model predicts it should be. 
B)  If the universe expanded at the rate originally predicted, then the parts seen in opposite directions would never have been in equilibrium with each other and should not exhibit the degree of isotropy observed. 
C)  Without modification, the standard theory suggests that an observer on a distant galaxy would not be able to see the Milky Way Galaxy because of the intense cosmological redshift. 
D)  As astronomers observe galaxies on the "horizon," the farthest distance obtainable, the standard theory predicts that the recessional velocity should approach the speed of light. 
A)  The universe is not as uniform as the standard cosmological model predicts it should be. 
B)  If the universe expanded at the rate originally predicted, then the parts seen in opposite directions would never have been in equilibrium with each other and should not exhibit the degree of isotropy observed. 
C)  Without modification, the standard theory suggests that an observer on a distant galaxy would not be able to see the Milky Way Galaxy because of the intense cosmological redshift. 
D)  As astronomers observe galaxies on the "horizon," the farthest distance obtainable, the standard theory predicts that the recessional velocity should approach the speed of light.

Question 6

If the universe had expanded at its original rate beyond the time when the strong nuclear force became a distinct force (about 10-35 s after the Big Bang), the isotropy problem would have arisen: Parts of the universe seen in opposite directions would never have been in equilibrium with each other and should not exhibit the degree of isotropy observed in the cosmic microwave background. The proposed solution to this problem is

Accepted Answer

A)  the cosmological redshift. 
B)  quark confinement. 
C)  cosmic inflation. 
D)  the Grand Unified Theory (GUT). 
A)  the cosmological redshift. 
B)  quark confinement. 
C)  cosmic inflation. 
D)  the Grand Unified Theory (GUT).

Question 7

The cosmic microwave background is found to be extremely uniform throughout space, with only very small fluctuations in intensity. The event that produced this remarkable smoothness in the early universe was

Accepted Answer

A)  the occurrence of the Big Bang everywhere in space at the same time. 
B)  the start of the production of matter in the universe, which smoothed out the irregularities in space. 
C)  an exemplar of Heisenberg's uncertainty principle, which prevented the concentration of radiant energy in localized volumes of space. 
D)  a sudden but brief period of rapid expansion (cosmic inflation) of the universe during the general expansion of the early universe. 
A)  the occurrence of the Big Bang everywhere in space at the same time. 
B)  the start of the production of matter in the universe, which smoothed out the irregularities in space. 
C)  an exemplar of Heisenberg's uncertainty principle, which prevented the concentration of radiant energy in localized volumes of space. 
D)  a sudden but brief period of rapid expansion (cosmic inflation) of the universe during the general expansion of the early universe.

Question 8

At about what time after the Big Bang did the universe pass through the transition from being radiation-dominated to being matter-dominated?

Accepted Answer

A)  at the Planck time, 10-43 s 
B)  about 15 billion years, as stars began to form 
C)  500,000 years 
D)  30,000 years 
A)  at the Planck time, 10-43 s 
B)  about 15 billion years, as stars began to form 
C)  500,000 years 
D)  30,000 years

Question 9

Why does the observable universe have an "edge"?

Accepted Answer

A)  Astronomers cannot see any farther out into space than the distance that light has traveled over the lifetime of the universe. 
B)  The density of neutrinos at the "edge" becomes so large that photons cannot penetrate this barrier, and this prevents observers from seeing beyond this point. 
C)  Absorbing matter prevents observers from seeing beyond a certain distance. 
D)  There are so many galaxies in the universe that every line of sight eventually hits a galaxy, stopping observers from seeing any farther. 
A)  Astronomers cannot see any farther out into space than the distance that light has traveled over the lifetime of the universe. 
B)  The density of neutrinos at the "edge" becomes so large that photons cannot penetrate this barrier, and this prevents observers from seeing beyond this point. 
C)  Absorbing matter prevents observers from seeing beyond a certain distance. 
D)  There are so many galaxies in the universe that every line of sight eventually hits a galaxy, stopping observers from seeing any farther.

Question 10

What experimental evidence do physicists have for the direct transformation of energy into matter?

Accepted Answer

A)  increase in the force upon a body when it is accelerated upward (e.g., in an elevator) 
B)  conversion of gamma-ray photons into electrons and antielectrons (i.e., positrons) 
C)  blueshift of light because of the motion of its source 
D)  relativistic increase in mass of an object when it is moving very rapidly 
A)  increase in the force upon a body when it is accelerated upward (e.g., in an elevator) 
B)  conversion of gamma-ray photons into electrons and antielectrons (i.e., positrons) 
C)  blueshift of light because of the motion of its source 
D)  relativistic increase in mass of an object when it is moving very rapidly

Question 11

Which two forces are infinite in extent?

Accepted Answer

A)  gravity and electromagnetism 
B)  gravity and the strong nuclear force 
C)  electromagnetism and the strong nuclear force 
D)  the two nuclear forces, strong and weak 
A)  gravity and electromagnetism 
B)  gravity and the strong nuclear force 
C)  electromagnetism and the strong nuclear force 
D)  the two nuclear forces, strong and weak

Question 12

Which of the four fundamental forces holds the electrons in the atom?

Accepted Answer

A)  strong nuclear force 
B)  gravitational force 
C)  weak nuclear force 
D)  electromagnetic force 
A)  strong nuclear force 
B)  gravitational force 
C)  weak nuclear force 
D)  electromagnetic force

Question 13

According to Hubble's law, how old is the universe? (H0 = Hubble constant)

Accepted Answer

A)  v/H0 (where v = recession velocity in km/s) 
B)  r/H0 (where r = distance in Mpc) 
C)  H0 
D)  1/H0 
A)  v/H0 (where v = recession velocity in km/s) 
B)  r/H0 (where r = distance in Mpc) 
C)  H0 
D)  1/H0

Question 14

Which of these statements describes the state of the universe during the inflationary epoch, from approximately 10-35 s to 10-33 s after the Big Bang?

Accepted Answer

A)  There were only two distinct forces: the strong, weak, and electromagnetic theories were all unified at that time. 
B)  There were only three distinct forces: gravity, strong, and electroweak forces. 
C)  Only quarks existed but they had not yet formed into other elementary particles. 
D)  Elementary particles such as neutrons and protons existed but they had not yet formed nuclei. 
A)  There were only two distinct forces: the strong, weak, and electromagnetic theories were all unified at that time. 
B)  There were only three distinct forces: gravity, strong, and electroweak forces. 
C)  Only quarks existed but they had not yet formed into other elementary particles. 
D)  Elementary particles such as neutrons and protons existed but they had not yet formed nuclei.

Question 15

Grand unified theories, or GUTs, predict that at temperatures above 1027 K, the

Accepted Answer

A)  strong and weak forces are indistinguishable from each other, but the other forces are different. 
B)  strong, weak, electromagnetic, and gravitational forces are indistinguishable from each other. 
C)  weak and electromagnetic forces are indistinguishable from each other, but the other forces are different. 
D)  strong, weak, and electromagnetic forces are indistinguishable from each other, but gravity is different. 
A)  strong and weak forces are indistinguishable from each other, but the other forces are different. 
B)  strong, weak, electromagnetic, and gravitational forces are indistinguishable from each other. 
C)  weak and electromagnetic forces are indistinguishable from each other, but the other forces are different. 
D)  strong, weak, and electromagnetic forces are indistinguishable from each other, but gravity is different.

Question 16

When is the weak nuclear force encountered?

Accepted Answer

A)  when a quark is transformed into another quark 
B)  when a positively charged nucleus repels another positively charged nucleus in the core of a star like the Sun 
C)  when two quarks interact inside a proton or neutron 
D)  when an atom absorbs a photon and one of the electrons in the atom is sent into a higher energy level 
A)  when a quark is transformed into another quark 
B)  when a positively charged nucleus repels another positively charged nucleus in the core of a star like the Sun 
C)  when two quarks interact inside a proton or neutron 
D)  when an atom absorbs a photon and one of the electrons in the atom is sent into a higher energy level

Question 17

Who first predicted the existence of the cosmic microwave background radiation, the radiation left over from the Big Bang?

Accepted Answer

A)  Ralph Alpher and George Gamow 
B)  Arno Penzias and Robert Wilson 
C)  Anthony Hewish and Jocelyn Bell 
D)  Robert Dicke and P. J. E. Peebles 
A)  Ralph Alpher and George Gamow 
B)  Arno Penzias and Robert Wilson 
C)  Anthony Hewish and Jocelyn Bell 
D)  Robert Dicke and P. J. E. Peebles

Question 18

How does the observed amount of visible matter in the universe compare with the amount required to make the geometry flat?

Accepted Answer

A)  The observed amount of visible matter is about 1/3 of the amount needed. 
B)  The observed amount of visible matter equals the amount needed, to within observational uncertainty. 
C)  The observed amount of visible matter is about twice the amount needed. 
D)  The observed amount of visible matter is about 1/25 of the amount needed. 
A)  The observed amount of visible matter is about 1/3 of the amount needed. 
B)  The observed amount of visible matter equals the amount needed, to within observational uncertainty. 
C)  The observed amount of visible matter is about twice the amount needed. 
D)  The observed amount of visible matter is about 1/25 of the amount needed.

Question 19

Where is Earth?

Accepted Answer

A)  at the exact center of an expanding universe, as shown by the universal expansion away from Earth in all directions 
B)  near the edge of an expanding universe, as shown by the microwave radiation coming to Earth from the edge 
C)  near but probably not right at the center of the universe, as shown by the fact that the edge is so far away from Earth 
D)  somewhere in an expanding universe but not in any special part of it 
A)  at the exact center of an expanding universe, as shown by the universal expansion away from Earth in all directions 
B)  near the edge of an expanding universe, as shown by the microwave radiation coming to Earth from the edge 
C)  near but probably not right at the center of the universe, as shown by the fact that the edge is so far away from Earth 
D)  somewhere in an expanding universe but not in any special part of it

Question 20

What kind of curvature (geometry of space) does the universe have if the universe is open?

Accepted Answer

A)  hyperbolic 
B)  parabolic 
C)  spherical 
D)  flat 
A)  hyperbolic 
B)  parabolic 
C)  spherical 
D)  flat

What caused the Big Bang and the expansion of the universe?

The very small detected irregularities in the uniformity of the cosmic microwave background are considered to be very important in the study of the evolution of the universe because they

The expansion of the universe takes place

During which period in the universe's history did its galaxies undergo the MOST vigorous period of star formation?

What is the isotropy (or horizon) problem?

The cosmic microwave background is found to be extremely uniform throughout space, with only very small fluctuations in intensity. The event that produced this remarkable smoothness in the early universe was

At about what time after the Big Bang did the universe pass through the transition from being radiation-dominated to being matter-dominated?

Why does the observable universe have an "edge"?

What experimental evidence do physicists have for the direct transformation of energy into matter?

Which two forces are infinite in extent?

Which of the four fundamental forces holds the electrons in the atom?

According to Hubble's law, how old is the universe? (H₀ = Hubble constant)

Which of these statements describes the state of the universe during the inflationary epoch, from approximately 10^-35 s to 10^-33 s after the Big Bang?

Grand unified theories, or GUTs, predict that at temperatures above 10²⁷ K, the

When is the weak nuclear force encountered?

Who first predicted the existence of the cosmic microwave background radiation, the radiation left over from the Big Bang?

How does the observed amount of visible matter in the universe compare with the amount required to make the geometry flat?

Where is Earth?

What kind of curvature (geometry of space) does the universe have if the universe is open?

Discovering the Night Sky

Gravitation and the Motion of the Planets

Light and Telescopes

Atomic Physics and Spectra

Exoplanets and the Formation of Planetary Systems

Formation of the Solar System

Earth and the Moon

The Other Terrestrial Planets

The Outer Planets

Vagabonds of the Solar System

The Sun: Our Extraordinary Star

Characterizing Stars

The Lives of Stars From Birth Through Middle Age

The Death of Stars

Black Holes: Matters of Gravity

The Milky Way Galaxy

Galaxies

Quasars and Other Active Galaxies

Astrobiology

Filters

Exam 19: Cosmology

What caused the Big Bang and the expansion of the universe?

The very small detected irregularities in the uniformity of the cosmic microwave background are considered to be very important in the study of the evolution of the universe because they

The expansion of the universe takes place

During which period in the universe's history did its galaxies undergo the MOST vigorous period of star formation?

What is the isotropy (or horizon) problem?

The cosmic microwave background is found to be extremely uniform throughout space, with only very small fluctuations in intensity. The event that produced this remarkable smoothness in the early universe was

At about what time after the Big Bang did the universe pass through the transition from being radiation-dominated to being matter-dominated?

Why does the observable universe have an "edge"?

What experimental evidence do physicists have for the direct transformation of energy into matter?

Which two forces are infinite in extent?

Which of the four fundamental forces holds the electrons in the atom?

According to Hubble's law, how old is the universe? (H0 = Hubble constant)

Which of these statements describes the state of the universe during the inflationary epoch, from approximately 10-35 s to 10-33 s after the Big Bang?

Grand unified theories, or GUTs, predict that at temperatures above 1027 K, the

When is the weak nuclear force encountered?

Who first predicted the existence of the cosmic microwave background radiation, the radiation left over from the Big Bang?

How does the observed amount of visible matter in the universe compare with the amount required to make the geometry flat?

Where is Earth?

What kind of curvature (geometry of space) does the universe have if the universe is open?

Discovering the Night Sky

Gravitation and the Motion of the Planets

Light and Telescopes

Atomic Physics and Spectra

Exoplanets and the Formation of Planetary Systems

Formation of the Solar System

Earth and the Moon

The Other Terrestrial Planets

The Outer Planets

Vagabonds of the Solar System

The Sun: Our Extraordinary Star

Characterizing Stars

The Lives of Stars From Birth Through Middle Age

The Death of Stars

Black Holes: Matters of Gravity

The Milky Way Galaxy

Galaxies

Quasars and Other Active Galaxies

Astrobiology

Filters

According to Hubble's law, how old is the universe? (H₀ = Hubble constant)

Which of these statements describes the state of the universe during the inflationary epoch, from approximately 10^-35 s to 10^-33 s after the Big Bang?

Grand unified theories, or GUTs, predict that at temperatures above 10²⁷ K, the