Question 1

What are the particles that make up protons and neutrons?

Accepted Answer

A)  quarks 
B)  muons 
C)  gravitons 
D)  neutrinos 
A)  quarks 
B)  muons 
C)  gravitons 
D)  neutrinos

Question 2

What do we mean when we say that the universe is homogeneous?

Accepted Answer

A)  At any given time and on a large enough scale, the universe looks the same at all locations. 
B)  There are no mass concentrations anywhere in the universe. 
C)  The universe is static and unchanging. 
D)  At any given time, the universe looks the same in all directions. 
A)  At any given time and on a large enough scale, the universe looks the same at all locations. 
B)  There are no mass concentrations anywhere in the universe. 
C)  The universe is static and unchanging. 
D)  At any given time, the universe looks the same in all directions.

Question 3

When Hubble did his early work on the expanding universe,he knew nothing about the cosmological redshift.He used the Doppler shift equations instead,but these gave him the correct answer.Why?

Accepted Answer

A)  These two sets of equations (Doppler shift and cosmological redshift) are the same and always give the same result for all cases. 
B)  Hubble was using only ordinary galaxies. If he had used galaxies with AGNs, the equations would not have worked. 
C)  Hubble was fortunate enough to use only galaxies for which the gravitational redshift and the cosmological redshift nearly cancel, so the Doppler shift provided essentially the whole effect. 
D)  Hubble was using only relatively nearby galaxies for which the non-relativistic cosmological redshift and the Doppler shift provide the same result. 
A)  These two sets of equations (Doppler shift and cosmological redshift) are the same and always give the same result for all cases. 
B)  Hubble was using only ordinary galaxies. If he had used galaxies with AGNs, the equations would not have worked. 
C)  Hubble was fortunate enough to use only galaxies for which the gravitational redshift and the cosmological redshift nearly cancel, so the Doppler shift provided essentially the whole effect. 
D)  Hubble was using only relatively nearby galaxies for which the non-relativistic cosmological redshift and the Doppler shift provide the same result.

Question 4

The predicted temperature of the early universe at which the four forces of nature would have been unified is _____ K.

Accepted Answer

A)  10²⁷ 
B)  10³² 
C)  10⁶ 
D)  10¹⁵ 
A)  10²⁷ 
B)  10³² 
C)  10⁶ 
D)  10¹⁵

Question 5

Measurement of the sizes of hot spots in the temperature distribution of the cosmic microwave background suggests that the universe is flat.Yet the combined density of all the matter and energy we see,plus the dark matter we infer,is only about a quarter of the critical density.What conclusion have we drawn from this discrepancy?

Accepted Answer

A)  The universe is not flat after all. 
B)  There must be a large amount of luminous matter and radiation in the universe that we have not yet found. 
C)  The universe is smaller than we have been assuming and thus the measured density is larger. 
D)  There is an entity to which we have given the name "dark energy" that contributes to the total density but that we cannot detect by the usual methods. 
A)  The universe is not flat after all. 
B)  There must be a large amount of luminous matter and radiation in the universe that we have not yet found. 
C)  The universe is smaller than we have been assuming and thus the measured density is larger. 
D)  There is an entity to which we have given the name "dark energy" that contributes to the total density but that we cannot detect by the usual methods.

Question 6

What is the range of the electromagnetic force (the maximum distance over which it acts)?

Accepted Answer

A)  10-¹⁵ m (1 femtometer, or roughly the size of a proton) 
B)  10-⁹ m (1 nanometer, or roughly the size of a hydrogen atom) 
C)  a few thousand meters, or roughly the size of Earth 
D)  infinity 
A)  10-¹⁵ m (1 femtometer, or roughly the size of a proton) 
B)  10-⁹ m (1 nanometer, or roughly the size of a hydrogen atom) 
C)  a few thousand meters, or roughly the size of Earth 
D)  infinity

Question 7

How was most of the helium in the universe created?

Accepted Answer

A)  by nuclear reactions in the cores of stars and then thrown out into space by supernovae 
B)  by high-energy processes during the collapse of pregalactic clouds during the formation of galaxies 
C)  by nuclear reactions during the first 3 minutes following the Big Bang 
D)  by the collision of cosmic rays with hydrogen nuclei in interstellar gas clouds 
A)  by nuclear reactions in the cores of stars and then thrown out into space by supernovae 
B)  by high-energy processes during the collapse of pregalactic clouds during the formation of galaxies 
C)  by nuclear reactions during the first 3 minutes following the Big Bang 
D)  by the collision of cosmic rays with hydrogen nuclei in interstellar gas clouds

Question 8

What is it that keeps localized regions of space,such as things on Earth,planetary systems,star clusters,and whole galaxies,from participating in the general expansion of the universe?

Accepted Answer

A)  their locations in places where irregularities in the chaotic Big Bang explosion permitted matter to condense 
B)  mutual gravitational attraction between objects in these systems 
C)  centrifugal force produced by the motion of the regions around a massive central object (e.g., the Sun, a supermassive black hole, etc.) 
D)  powerful and all-pervading gravitational pulls from the central supermassive black holes of galaxies that holds everything in the galaxies in place 
A)  their locations in places where irregularities in the chaotic Big Bang explosion permitted matter to condense 
B)  mutual gravitational attraction between objects in these systems 
C)  centrifugal force produced by the motion of the regions around a massive central object (e.g., the Sun, a supermassive black hole, etc.) 
D)  powerful and all-pervading gravitational pulls from the central supermassive black holes of galaxies that holds everything in the galaxies in place

Question 9

We presently consider the universe to be matter dominated.In this stage,the number of photons:

Accepted Answer

A)  vastly outnumbers the number of particles. 
B)  is vastly outnumbered by the number of particles. 
C)  is greatly outnumbered by the number of particles, but is less than the number of particles plus antiparticles. 
D)  is close to being equal to the number of particles 
A)  vastly outnumbers the number of particles. 
B)  is vastly outnumbered by the number of particles. 
C)  is greatly outnumbered by the number of particles, but is less than the number of particles plus antiparticles. 
D)  is close to being equal to the number of particles

Question 10

How does the observed amount of visible matter in the universe compare with the amount required to just close the universe?

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 1/200 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 1/200 of the amount needed.

Question 11

In a primordial,pre-galactic gas cloud,what is believed to have been the MOST important condition that caused the cloud to become a spiral galaxy (as opposed to some other type of galaxy)?

Accepted Answer

A)  The cloud started off with a lot of dust and heavy elements. 
B)  The initial rate of star formation was high. 
C)  The cloud started off flattened and disk-shaped before it collapsed. 
D)  The initial rate of star formation was low. 
A)  The cloud started off with a lot of dust and heavy elements. 
B)  The initial rate of star formation was high. 
C)  The cloud started off flattened and disk-shaped before it collapsed. 
D)  The initial rate of star formation was low.

Question 12

How many fundamental forces are there in nature at the present time under normal conditions?

Accepted Answer

A)  three: strong, electromagnetic, and gravitational 
B)  six: color, strong, weak, magnetic, electric, and gravitational 
C)  four: strong, weak, electromagnetic, and gravitational 
D)  five: strong, weak, magnetic, electric, and gravitational 
A)  three: strong, electromagnetic, and gravitational 
B)  six: color, strong, weak, magnetic, electric, and gravitational 
C)  four: strong, weak, electromagnetic, and gravitational 
D)  five: strong, weak, magnetic, electric, and gravitational

Question 13

How does the observed total amount of matter in the universe,including dark matter,compare with the amount of matter required to just close the universe?

Accepted Answer

A)  The observed total amount of matter equals the amount needed, to within observational uncertainty. 
B)  The observed total amount of matter is about 1/3 of the amount needed. 
C)  The observed total amount of matter is about twice the amount needed. 
D)  The observed total amount of matter is about 1/200 of the amount needed. 
A)  The observed total amount of matter equals the amount needed, to within observational uncertainty. 
B)  The observed total amount of matter is about 1/3 of the amount needed. 
C)  The observed total amount of matter is about twice the amount needed. 
D)  The observed total amount of matter is about 1/200 of the amount needed.

Question 14

Which statement about Hubble's original data is CORRECT?

Accepted Answer

A)  Hubble's original data were just from the Local Group of galaxies. But the Hubble expansion applies to galaxy-to-galaxy distances within galaxy clusters, so he was able to see the universal expansion within these data. 
B)  Hubble's original data were for superclusters of galaxies, so he was able to see the effect of the expansion within these data. 
C)  The Hubble expansion does not apply to galaxy-to-galaxy distances, but the Doppler effect does. Since Hubble used only data from the Local Group, he was actually measuring only Doppler shifts. 
D)  The Hubble expansion does not apply to galaxy-to-galaxy distances, but it does apply to cluster-to-cluster distances. Hubble's original data were included galaxies beyond the Local Group, so he was able to see the universal expansion within these data. 
A)  Hubble's original data were just from the Local Group of galaxies. But the Hubble expansion applies to galaxy-to-galaxy distances within galaxy clusters, so he was able to see the universal expansion within these data. 
B)  Hubble's original data were for superclusters of galaxies, so he was able to see the effect of the expansion within these data. 
C)  The Hubble expansion does not apply to galaxy-to-galaxy distances, but the Doppler effect does. Since Hubble used only data from the Local Group, he was actually measuring only Doppler shifts. 
D)  The Hubble expansion does not apply to galaxy-to-galaxy distances, but it does apply to cluster-to-cluster distances. Hubble's original data were included galaxies beyond the Local Group, so he was able to see the universal expansion within these data.

Question 15

The cosmic background radiation is the:

Accepted Answer

A)  result of the radioactive decay of heavier, unstable elements produced in supernova explosions. 
B)  faint glow along the elliptic, caused by sunlight scattering from dust particles. 
C)  electromagnetic remnants of the explosion in which the universe was born. 
D)  radio noise from hot gas in rich clusters of galaxies. 
A)  result of the radioactive decay of heavier, unstable elements produced in supernova explosions. 
B)  faint glow along the elliptic, caused by sunlight scattering from dust particles. 
C)  electromagnetic remnants of the explosion in which the universe was born. 
D)  radio noise from hot gas in rich clusters of galaxies.

Question 16

What is M-theory?

Accepted Answer

A)  a theory of the universe in which all galaxies began as a common type "M galaxy" and then evolved into the types we see today 
B)  a type of dark matter theory in which the dark matter is made of "M" particles 
C)  a superstring theory in which there are 11 dimensions, instead of the usual ten, and all five string theories are equivalent 
D)  a cosmologic theory in which cosmic inflation occurred multiple times rather than just once 
A)  a theory of the universe in which all galaxies began as a common type "M galaxy" and then evolved into the types we see today 
B)  a type of dark matter theory in which the dark matter is made of "M" particles 
C)  a superstring theory in which there are 11 dimensions, instead of the usual ten, and all five string theories are equivalent 
D)  a cosmologic theory in which cosmic inflation occurred multiple times rather than just once

Question 17

When a gamma-ray photon undergoes pair production,what is one possibility for the final products?

Accepted Answer

A)  an electron and a positron (the antielectron) 
B)  an electron and an antineutrino 
C)  a proton, an electron, and an antineutrino 
D)  two X-ray photons, each with half the energy of the original gamma ray 
A)  an electron and a positron (the antielectron) 
B)  an electron and an antineutrino 
C)  a proton, an electron, and an antineutrino 
D)  two X-ray photons, each with half the energy of the original gamma ray

Question 18

During the epoch of cosmic inflation,which property of the universe changed?

Accepted Answer

A)  temperature 
B)  pressure 
C)  density 
D)  scale factor of spacetime 
A)  temperature 
B)  pressure 
C)  density 
D)  scale factor of spacetime

Question 19

Symmetry breaking is associated with which one of the fundamental forces?

Accepted Answer

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

Question 20

During the formation of the universe,where did the density enhancements come from that subsequently collapsed to form superclusters of galaxies?

Accepted Answer

A)  turbulence during the time when the universe was opaque, which left denser regions that were free to collapse when the universe became transparent 
B)  quantum fluctuations in the density of matter during the early Big Bang, which were later expanded by inflation 
C)  spatial variations in the rate heating from pair annihilation after the first second of the Big Bang 
D)  random gravitational fragmentation of the matter in the universe after the era of recombination 
A)  turbulence during the time when the universe was opaque, which left denser regions that were free to collapse when the universe became transparent 
B)  quantum fluctuations in the density of matter during the early Big Bang, which were later expanded by inflation 
C)  spatial variations in the rate heating from pair annihilation after the first second of the Big Bang 
D)  random gravitational fragmentation of the matter in the universe after the era of recombination

What are the particles that make up protons and neutrons?

What do we mean when we say that the universe is homogeneous?

When Hubble did his early work on the expanding universe,he knew nothing about the cosmological redshift.He used the Doppler shift equations instead,but these gave him the correct answer.Why?

The predicted temperature of the early universe at which the four forces of nature would have been unified is _____ K.

What is the range of the electromagnetic force (the maximum distance over which it acts)?

How was most of the helium in the universe created?

What is it that keeps localized regions of space,such as things on Earth,planetary systems,star clusters,and whole galaxies,from participating in the general expansion of the universe?

We presently consider the universe to be matter dominated.In this stage,the number of photons:

How does the observed amount of visible matter in the universe compare with the amount required to just close the universe?

In a primordial,pre-galactic gas cloud,what is believed to have been the MOST important condition that caused the cloud to become a spiral galaxy (as opposed to some other type of galaxy)?

How many fundamental forces are there in nature at the present time under normal conditions?

How does the observed total amount of matter in the universe,including dark matter,compare with the amount of matter required to just close the universe?

Which statement about Hubble's original data is CORRECT?

The cosmic background radiation is the:

What is M-theory?

When a gamma-ray photon undergoes pair production,what is one possibility for the final products?

During the epoch of cosmic inflation,which property of the universe changed?

Symmetry breaking is associated with which one of the fundamental forces?

During the formation of the universe,where did the density enhancements come from that subsequently collapsed to form superclusters of galaxies?

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

What are the particles that make up protons and neutrons?

What do we mean when we say that the universe is homogeneous?

When Hubble did his early work on the expanding universe,he knew nothing about the cosmological redshift.He used the Doppler shift equations instead,but these gave him the correct answer.Why?

The predicted temperature of the early universe at which the four forces of nature would have been unified is _____ K.

What is the range of the electromagnetic force (the maximum distance over which it acts)?

How was most of the helium in the universe created?

What is it that keeps localized regions of space,such as things on Earth,planetary systems,star clusters,and whole galaxies,from participating in the general expansion of the universe?

We presently consider the universe to be matter dominated.In this stage,the number of photons:

How does the observed amount of visible matter in the universe compare with the amount required to just close the universe?

In a primordial,pre-galactic gas cloud,what is believed to have been the MOST important condition that caused the cloud to become a spiral galaxy (as opposed to some other type of galaxy)?

How many fundamental forces are there in nature at the present time under normal conditions?

How does the observed total amount of matter in the universe,including dark matter,compare with the amount of matter required to just close the universe?

Which statement about Hubble's original data is CORRECT?

The cosmic background radiation is the:

What is M-theory?

When a gamma-ray photon undergoes pair production,what is one possibility for the final products?

During the epoch of cosmic inflation,which property of the universe changed?

Symmetry breaking is associated with which one of the fundamental forces?

During the formation of the universe,where did the density enhancements come from that subsequently collapsed to form superclusters of galaxies?

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