Question 1

If the geometry of space is spherical,what is the future of the universe?

Accepted Answer

A)  The future of the universe is not related to the geometry of space. 
B)  The universe will expand forever, not stopping even when infinite time has elapsed. 
C)  The universe will hardly expand forever; if it has any more matter in it than it does, it will eventually stop expanding and start to collapse. 
D)  The universe will expand to a maximum size and then collapse into a Big Crunch. 
A)  The future of the universe is not related to the geometry of space. 
B)  The universe will expand forever, not stopping even when infinite time has elapsed. 
C)  The universe will hardly expand forever; if it has any more matter in it than it does, it will eventually stop expanding and start to collapse. 
D)  The universe will expand to a maximum size and then collapse into a Big Crunch.

Question 2

Which statement is a CORRECT description of the expansion of the universe?

Accepted Answer

A)  Spacetime is something real, with galaxies inside it; as spacetime expands, the galaxies (or superclusters of galaxies) are carried along by the expansion. 
B)  Space is a vacuum, but the vacuum has real properties; as galaxies (or superclusters of galaxies) hurtle outward, the expansion is gradually slowing down by the resistance of space to the passage of the galaxies. 
C)  Spacetime is static, but dark matter, which is concentrated in the outer part of the universe, pulls outward on the galaxies. 
D)  Space is a vacuum, which is really nothing at all; the galaxies (or superclusters of galaxies) are hurtling outward through this nothingness. 
A)  Spacetime is something real, with galaxies inside it; as spacetime expands, the galaxies (or superclusters of galaxies) are carried along by the expansion. 
B)  Space is a vacuum, but the vacuum has real properties; as galaxies (or superclusters of galaxies) hurtle outward, the expansion is gradually slowing down by the resistance of space to the passage of the galaxies. 
C)  Spacetime is static, but dark matter, which is concentrated in the outer part of the universe, pulls outward on the galaxies. 
D)  Space is a vacuum, which is really nothing at all; the galaxies (or superclusters of galaxies) are hurtling outward through this nothingness.

Question 3

Physicists speculate that,early in its history,the universe shifted from a "false vacuum" state to a "true vacuum" state.What is the significance of this transition?

Accepted Answer

A)  The "false vacuum" describes the state of the universe before the Planck time, 10-⁴³ s. During this time, the laws of physics as we currently understand them did not apply. 
B)  The transition was from a high-energy state to a low-energy state. The consequent release of energy fueled the inflationary epoch. 
C)  The transition was one from a low-energy state to a high-energy state. The consequent intake of energy caused the universe at the end of the inflationary epoch to be much cooler than it had been at the beginning of the inflationary epoch. 
D)  In its transition to the true vacuum, the universe became trapped in a state of minimum energy, unable to expand or contract. 
A)  The "false vacuum" describes the state of the universe before the Planck time, 10-⁴³ s. During this time, the laws of physics as we currently understand them did not apply. 
B)  The transition was from a high-energy state to a low-energy state. The consequent release of energy fueled the inflationary epoch. 
C)  The transition was one from a low-energy state to a high-energy state. The consequent intake of energy caused the universe at the end of the inflationary epoch to be much cooler than it had been at the beginning of the inflationary epoch. 
D)  In its transition to the true vacuum, the universe became trapped in a state of minimum energy, unable to expand or contract.

Question 4

What is the cosmic light horizon?

Accepted Answer

A)  The cosmic light horizon is the distance beyond which we cannot see because light cannot have traveled any farther in the finite age of the universe. 
B)  The cosmic light horizon is the distance beyond which we cannot see because no stars or galaxies had yet formed at those distances (because we see back in time as we look out into space). 
C)  The cosmic light horizon is the distance beyond which our own radio and television signals have not traveled through the universe. 
D)  The cosmic light horizon is the distance beyond which we cannot see because of absorbing matter in the universe. 
A)  The cosmic light horizon is the distance beyond which we cannot see because light cannot have traveled any farther in the finite age of the universe. 
B)  The cosmic light horizon is the distance beyond which we cannot see because no stars or galaxies had yet formed at those distances (because we see back in time as we look out into space). 
C)  The cosmic light horizon is the distance beyond which our own radio and television signals have not traveled through the universe. 
D)  The cosmic light horizon is the distance beyond which we cannot see because of absorbing matter in the universe.

Question 5

The cosmic background radiation that was left over after the Big Bang of the universe and that pervades all observable space has an effective blackbody temperature of approximately:

Accepted Answer

A)  273 K. 
B)  0 K. 
C)  10 K. 
D)  3 K. 
A)  273 K. 
B)  0 K. 
C)  10 K. 
D)  3 K.

Question 6

For how long did continuous star formation last in spiral galaxies?

Accepted Answer

A)  about the first 8 to 10 billion years of the galaxy's life 
B)  about the first one billion years of the galaxy's life 
C)  about the first one million years of the galaxy's life 
D)  continuously throughout the galaxy's life, right to the present day 
A)  about the first 8 to 10 billion years of the galaxy's life 
B)  about the first one billion years of the galaxy's life 
C)  about the first one million years of the galaxy's life 
D)  continuously throughout the galaxy's life, right to the present day

Question 7

What is the range of the strong nuclear force compared with the size of the nucleus,10-¹⁴ m?

Accepted Answer

A)  the same since it is the strong force that holds the nucleus together 
B)  10 times larger than the size of an atomic nucleus 
C)  infinite since it has no limit 
D)  10 times smaller than the size of an atomic nucleus 
A)  the same since it is the strong force that holds the nucleus together 
B)  10 times larger than the size of an atomic nucleus 
C)  infinite since it has no limit 
D)  10 times smaller than the size of an atomic nucleus

Question 8

What designation do we give to the first stars?

Accepted Answer

A)  Population 0 
B)  Population I 
C)  Population II 
D)  Population III 
A)  Population 0 
B)  Population I 
C)  Population II 
D)  Population III

Question 9

Within which time frame from the initial Big Bang do we believe all four fundamental forces of nature were united into a single force?

Accepted Answer

A)  t = 0 to 10⁶ years, when radiation dominated the universe 
B)  t = 0 to 1 s, when photons interchanged freely with electron-positron pairs 
C)  t = 0 to 10-³⁵ s, when the strong nuclear force "froze out" of the universe 
D)  t = 0 to 10-⁴³ s, the Planck time, when gravity "froze out" of the universe 
A)  t = 0 to 10⁶ years, when radiation dominated the universe 
B)  t = 0 to 1 s, when photons interchanged freely with electron-positron pairs 
C)  t = 0 to 10-³⁵ s, when the strong nuclear force "froze out" of the universe 
D)  t = 0 to 10-⁴³ s, the Planck time, when gravity "froze out" of the universe

Question 10

Why does the observable universe have an "edge"?

Accepted Answer

A)  We 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 us from seeing beyond this point. 
C)  Absorbing matter prevents us 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 us from seeing any farther. 
A)  We 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 us from seeing beyond this point. 
C)  Absorbing matter prevents us 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 us from seeing any farther.

Question 11

Which statement does NOT correctly describe the universe at the era of recombination?

Accepted Answer

A)  The temperature of the universe was about 3 K. 
B)  The universe was about 500,000 years old. 
C)  The universe became transparent to radiation. 
D)  Electrons and protons combined to form neutral hydrogen atoms. 
A)  The temperature of the universe was about 3 K. 
B)  The universe was about 500,000 years old. 
C)  The universe became transparent to radiation. 
D)  Electrons and protons combined to form neutral hydrogen atoms.

Question 12

Which cosmological problem is "dark energy" believed to solve?

Accepted Answer

A)  Why is the universe flat? 
B)  Why did the universe suddenly inflate during the Big Bang? 
C)  Why is the temperature of the cosmic background radiation so smooth (isotropic) around the sky? 
D)  Why is the night sky dark? 
A)  Why is the universe flat? 
B)  Why did the universe suddenly inflate during the Big Bang? 
C)  Why is the temperature of the cosmic background radiation so smooth (isotropic) around the sky? 
D)  Why is the night sky dark?

Question 13

Opposite sides of the universe have the same temperature,yet according to the standard Big Bang theory,these points are too far apart for light to have traveled from one to the other in the age of the universe; that is,they cannot have exchanged heat to even out their temperature.Why,then,do they have the same temperature?

Accepted Answer

A)  Light (and heat) could travel much faster in the early universe, allowing them to exchange heat while the universe was young. 
B)  The expansion of the universe has always been the same everywhere; therefore, all parts of the universe have the same temperature, regardless of whether they have ever exchanged heat or not. 
C)  It is pure coincidence that opposite sides of the universe have the same temperature. 
D)  Opposite sides of the universe were originally close together and evened out their temperature, and then a rapid inflation of the universe carried them far apart. 
A)  Light (and heat) could travel much faster in the early universe, allowing them to exchange heat while the universe was young. 
B)  The expansion of the universe has always been the same everywhere; therefore, all parts of the universe have the same temperature, regardless of whether they have ever exchanged heat or not. 
C)  It is pure coincidence that opposite sides of the universe have the same temperature. 
D)  Opposite sides of the universe were originally close together and evened out their temperature, and then a rapid inflation of the universe carried them far apart.

Question 14

In relation to the universe,what does isotropy mean?

Accepted Answer

A)  The universe has the same expansion speed at all distances. 
B)  The universe is the same at all distances. 
C)  The universe at any given distance is the same at all times. 
D)  The universe looks the same in all directions. 
A)  The universe has the same expansion speed at all distances. 
B)  The universe is the same at all distances. 
C)  The universe at any given distance is the same at all times. 
D)  The universe looks the same in all directions.

Question 15

If the cosmological constant exists,what physical effect is believed to create it?

Accepted Answer

A)  New matter is constantly being created in the expanding voids between superclusters of galaxies, and the energy released by this creation accelerates the expansion of the universe. 
B)  No one knows. The cosmological constant has been hypothesized to exist because we see the universal expansion accelerating, but its source is still a mystery. 
C)  Energy released by nuclear reactions in stars and then emitted into space is heating the universe and accelerating its expansion. 
D)  Virtual particles that constantly appear and disappear add energy to empty space, and this vacuum energy provides a constant repulsive force that accelerates the universe. 
A)  New matter is constantly being created in the expanding voids between superclusters of galaxies, and the energy released by this creation accelerates the expansion of the universe. 
B)  No one knows. The cosmological constant has been hypothesized to exist because we see the universal expansion accelerating, but its source is still a mystery. 
C)  Energy released by nuclear reactions in stars and then emitted into space is heating the universe and accelerating its expansion. 
D)  Virtual particles that constantly appear and disappear add energy to empty space, and this vacuum energy provides a constant repulsive force that accelerates the universe.

Question 16

When Hubble first calculated the recessional speeds of galaxies in the 1920s,he used the:

Accepted Answer

A)  Doppler shift relationship. This was an error, and the calculations had to be repeated using the cosmological redshift relationship. 
B)  Doppler shift relationship. This was an error, and the calculations had to be repeated using the gravitational redshift relationship. 
C)  Doppler shift relationship. This was correct because the non-relativistic cosmological redshift relationship gives the same result. 
D)  the cosmological redshift relationship. This was an error, and the calculations had to be repeated using the Doppler shift relationship. 
A)  Doppler shift relationship. This was an error, and the calculations had to be repeated using the cosmological redshift relationship. 
B)  Doppler shift relationship. This was an error, and the calculations had to be repeated using the gravitational redshift relationship. 
C)  Doppler shift relationship. This was correct because the non-relativistic cosmological redshift relationship gives the same result. 
D)  the cosmological redshift relationship. This was an error, and the calculations had to be repeated using the Doppler shift relationship.

Question 17

Why did the formation of particle-antiparticle pairs (such as protons and antiprotons)from gamma rays come to an end in the first second after start of the Big Bang?

Accepted Answer

A)  Expansion of the universe carried the gamma rays too far apart for them to collide and form particle-antiparticle pairs. 
B)  The gamma-ray energy decreased as the universe expanded. 
C)  The universe became transparent to radiation, so gamma rays and particles no longer interacted. 
D)  The formation of particle-antiparticle pairs exhausted the supply of gamma rays, preventing further formation of particle-antiparticle pairs. 
A)  Expansion of the universe carried the gamma rays too far apart for them to collide and form particle-antiparticle pairs. 
B)  The gamma-ray energy decreased as the universe expanded. 
C)  The universe became transparent to radiation, so gamma rays and particles no longer interacted. 
D)  The formation of particle-antiparticle pairs exhausted the supply of gamma rays, preventing further formation of particle-antiparticle pairs.

Question 18

The first 10-⁴³ s of the age of the universe,during which all four fundamental forces were united,is called the:

Accepted Answer

A)  Planck era. 
B)  inflationary era. 
C)  event horizon. 
D)  Hubble time. 
A)  Planck era. 
B)  inflationary era. 
C)  event horizon. 
D)  Hubble time.

Question 19

Einstein introduced a "cosmological constant" into his formulation of the structure of the universe as described by his general theory of relativity.How did he envision that this cosmological constant would manifest itself?

Accepted Answer

A)  as many "white holes" that would contribute matter to an expanding universe to maintain constant density, as required by the cosmological principle-a continuous creation universe 
B)  as an extra "gravity" that would hold the universe against continuous expansion 
C)  as antimatter that, by annihilating real matter, would translate matter into energy, thereby maintaining a constant mass density in a condensing universe 
D)  as a form of energy that, on its own, would make the universe expand-a form of antigravity 
A)  as many "white holes" that would contribute matter to an expanding universe to maintain constant density, as required by the cosmological principle-a continuous creation universe 
B)  as an extra "gravity" that would hold the universe against continuous expansion 
C)  as antimatter that, by annihilating real matter, would translate matter into energy, thereby maintaining a constant mass density in a condensing universe 
D)  as a form of energy that, on its own, would make the universe expand-a form of antigravity

Question 20

Recent results from very bright supernovae in very distant galaxies seem to indicate that the expansion of the universe:

Accepted Answer

A)  has now stopped and the universe will shortly begin to contract again toward a Big Crunch. 
B)  is decelerating (slowing down). 
C)  is continuing at a constant rate and has done so since just after the Big Bang. 
D)  is accelerating (speeding up). 
A)  has now stopped and the universe will shortly begin to contract again toward a Big Crunch. 
B)  is decelerating (slowing down). 
C)  is continuing at a constant rate and has done so since just after the Big Bang. 
D)  is accelerating (speeding up).

If the geometry of space is spherical,what is the future of the universe?

Which statement is a CORRECT description of the expansion of the universe?

Physicists speculate that,early in its history,the universe shifted from a "false vacuum" state to a "true vacuum" state.What is the significance of this transition?

What is the cosmic light horizon?

The cosmic background radiation that was left over after the Big Bang of the universe and that pervades all observable space has an effective blackbody temperature of approximately:

For how long did continuous star formation last in spiral galaxies?

What is the range of the strong nuclear force compared with the size of the nucleus,10-¹⁴ m?

What designation do we give to the first stars?

Within which time frame from the initial Big Bang do we believe all four fundamental forces of nature were united into a single force?

Why does the observable universe have an "edge"?

Which statement does NOT correctly describe the universe at the era of recombination?

Which cosmological problem is "dark energy" believed to solve?

In relation to the universe,what does isotropy mean?

If the cosmological constant exists,what physical effect is believed to create it?

When Hubble first calculated the recessional speeds of galaxies in the 1920s,he used the:

Why did the formation of particle-antiparticle pairs (such as protons and antiprotons)from gamma rays come to an end in the first second after start of the Big Bang?

The first 10-⁴³ s of the age of the universe,during which all four fundamental forces were united,is called the:

Einstein introduced a "cosmological constant" into his formulation of the structure of the universe as described by his general theory of relativity.How did he envision that this cosmological constant would manifest itself?

Recent results from very bright supernovae in very distant galaxies seem to indicate that the expansion of the universe:

Discovering the Night Sky

Gravitation and the Waltz of the Planets

Light and Telescopes

Formation of the Solar System and Other Planetary Systems

Exoplanets

The Terrestrial Planets and Their Moons

The Outer Planets and Their Moons

Vagabonds of the Solar System

The Sun: Our Extraordinary Ordinary Star

Characterizing Stars

The Lives of the Stars From Birth Through Middle Age

The Deaths and Remnants of Stars

The Galaxies

Astrobiology

Filters

Exam 14: Cosmology

If the geometry of space is spherical,what is the future of the universe?

Which statement is a CORRECT description of the expansion of the universe?

Physicists speculate that,early in its history,the universe shifted from a "false vacuum" state to a "true vacuum" state.What is the significance of this transition?

What is the cosmic light horizon?

The cosmic background radiation that was left over after the Big Bang of the universe and that pervades all observable space has an effective blackbody temperature of approximately:

For how long did continuous star formation last in spiral galaxies?

What is the range of the strong nuclear force compared with the size of the nucleus,10-¹⁴ m?

What designation do we give to the first stars?

Within which time frame from the initial Big Bang do we believe all four fundamental forces of nature were united into a single force?

Why does the observable universe have an "edge"?

Which statement does NOT correctly describe the universe at the era of recombination?

Which cosmological problem is "dark energy" believed to solve?

In relation to the universe,what does isotropy mean?

If the cosmological constant exists,what physical effect is believed to create it?

When Hubble first calculated the recessional speeds of galaxies in the 1920s,he used the:

Why did the formation of particle-antiparticle pairs (such as protons and antiprotons)from gamma rays come to an end in the first second after start of the Big Bang?

The first 10-⁴³ s of the age of the universe,during which all four fundamental forces were united,is called the:

Einstein introduced a "cosmological constant" into his formulation of the structure of the universe as described by his general theory of relativity.How did he envision that this cosmological constant would manifest itself?

Recent results from very bright supernovae in very distant galaxies seem to indicate that the expansion of the universe:

Discovering the Night Sky

Gravitation and the Waltz of the Planets

Light and Telescopes

Formation of the Solar System and Other Planetary Systems

Exoplanets

The Terrestrial Planets and Their Moons

The Outer Planets and Their Moons

Vagabonds of the Solar System

The Sun: Our Extraordinary Ordinary Star

Characterizing Stars

The Lives of the Stars From Birth Through Middle Age

The Deaths and Remnants of Stars

The Galaxies

Astrobiology

Filters