Question 1

Why would we expect the rate of expansion of the universe to be slowing down?

Accepted Answer

A)  The gravitational pull of all objects in the universe on each other would lead to slowdown. 
B)  All expansions after explosions naturally slow down with time. 
C)  Galaxies feel a kind of friction as they move through space, which slows them down. 
D)  The greater the distance between two objects (such as galaxies or superclusters), the harder it is to push them farther apart. 
A)  The gravitational pull of all objects in the universe on each other would lead to slowdown. 
B)  All expansions after explosions naturally slow down with time. 
C)  Galaxies feel a kind of friction as they move through space, which slows them down. 
D)  The greater the distance between two objects (such as galaxies or superclusters), the harder it is to push them farther apart.

Question 2

The Big Bang theory is the most widely accepted model of the early universe today.Which statement is NOT one of the reasons for this?

Accepted Answer

A)  The observed expansion of the universe is consistent with the Big Bang theory. 
B)  No alternate theories have been proposed. 
C)  The observed cosmic microwave background is consistent with the Big Bang theory. 
D)  The observed cosmic neutrino background is consistent with the Big Bang theory. 
A)  The observed expansion of the universe is consistent with the Big Bang theory. 
B)  No alternate theories have been proposed. 
C)  The observed cosmic microwave background is consistent with the Big Bang theory. 
D)  The observed cosmic neutrino background is consistent with the Big Bang theory.

Question 3

In modern particle physics,the proton and the neutron are now thought to be composed of more fundamental particles called:

Accepted Answer

A)  photons. 
B)  gluons. 
C)  neutrinos. 
D)  quarks. 
A)  photons. 
B)  gluons. 
C)  neutrinos. 
D)  quarks.

Question 4

What significant event occurred about 500,000 years after the start of the Big Bang?

Accepted Answer

A)  All the galaxies we see today formed. 
B)  Electrons and nuclei combined to form neutral atoms. 
C)  Quarks became confined. 
D)  The formation of helium stopped. 
A)  All the galaxies we see today formed. 
B)  Electrons and nuclei combined to form neutral atoms. 
C)  Quarks became confined. 
D)  The formation of helium stopped.

Question 5

Which scientist discovered that the equations he had derived predicted an expanding universe,then modified his equations to eliminate this expansion?

Accepted Answer

A)  Albert Einstein 
B)  Isaac Newton 
C)  Stephen Hawking 
D)  Edwin Hubble 
A)  Albert Einstein 
B)  Isaac Newton 
C)  Stephen Hawking 
D)  Edwin Hubble

Question 6

As currently understood,what happens to the density of matter and the density of dark energy as the universe expands?

Accepted Answer

A)  Both the density of matter and the density of dark energy increase as the universe expands. 
B)  The matter density decreases, but the density of dark energy increases. 
C)  The matter density decreases, but the density of dark energy remains constant. 
D)  Both the density of matter and the density of dark energy decrease as the universe expands. 
A)  Both the density of matter and the density of dark energy increase as the universe expands. 
B)  The matter density decreases, but the density of dark energy increases. 
C)  The matter density decreases, but the density of dark energy remains constant. 
D)  Both the density of matter and the density of dark energy decrease as the universe expands.

Question 7

Newton reached the conclusion that the universe must consist of an infinite expanse of stars because:

Accepted Answer

A)  he and his colleagues had observed the uniform distribution of stars all over the sky. 
B)  he was unable to detect the movement of stars around a common center, which his theory required for stability against collapse in a finite universe. 
C)  of his religious conviction that the creator would create nothing less than an infinite universe. 
D)  he reasoned that if stars were not uniformly distributed everywhere, then denser portions of the universe would clump together under their own gravity. 
A)  he and his colleagues had observed the uniform distribution of stars all over the sky. 
B)  he was unable to detect the movement of stars around a common center, which his theory required for stability against collapse in a finite universe. 
C)  of his religious conviction that the creator would create nothing less than an infinite universe. 
D)  he reasoned that if stars were not uniformly distributed everywhere, then denser portions of the universe would clump together under their own gravity.

Question 8

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

Accepted Answer

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

Question 9

The cosmic background radiation is:

Accepted Answer

A)  the flux of visible radiation in empty space, contributed by all visible stars in the universe. 
B)  the radio noise generated by Earthbound transmitters, spreading out into space since about 1920. 
C)  the beam of atomic nuclei known as cosmic rays that continuously rain down on Earth from all directions in space. 
D)  low-intensity radio noise, with a 3 K blackbody temperature, almost uniform in intensity in all directions. 
A)  the flux of visible radiation in empty space, contributed by all visible stars in the universe. 
B)  the radio noise generated by Earthbound transmitters, spreading out into space since about 1920. 
C)  the beam of atomic nuclei known as cosmic rays that continuously rain down on Earth from all directions in space. 
D)  low-intensity radio noise, with a 3 K blackbody temperature, almost uniform in intensity in all directions.

Question 10

Physicists are attempting to develop a Theory of Everything.What would be unique about such a theory?

Accepted Answer

A)  It would describe both relativistic and non-relativistic physics. 
B)  It would include the actions of the electroweak force. 
C)  It would be able to describe the universe during the Planck era. 
D)  It would be able to describe the universe before the Planck era. 
A)  It would describe both relativistic and non-relativistic physics. 
B)  It would include the actions of the electroweak force. 
C)  It would be able to describe the universe during the Planck era. 
D)  It would be able to describe the universe before the Planck era.

Question 11

The four physical forces at work in the universe are gravitational,electromagnetic,strong nuclear,and weak nuclear forces.Which two of these are very short-ranged,extending over distances of only about 10-¹⁵ m?

Accepted Answer

A)  strong nuclear and electromagnetic forces 
B)  electromagnetic and weak nuclear forces 
C)  strong and weak nuclear forces 
D)  gravitational and electromagnetic forces 
A)  strong nuclear and electromagnetic forces 
B)  electromagnetic and weak nuclear forces 
C)  strong and weak nuclear forces 
D)  gravitational and electromagnetic forces

Question 12

When did the inflationary period begin?

Accepted Answer

A)  when the strong force became a separate force 
B)  when pair production ceased 
C)  when gravity became a separate force 
D)  when the electromagnetic force became a separate force 
A)  when the strong force became a separate force 
B)  when pair production ceased 
C)  when gravity became a separate force 
D)  when the electromagnetic force became a separate force

Question 13

Because of the travel time of light,we see more distant parts of the universe as they were when the universe was younger,but we cannot see back "into" times when the universe was opaque and light could not travel freely.Using photons,then,what is the furthest back in time that we can see as we look out into the universe?

Accepted Answer

A)  1/1,000,000 seconds after the start of the Big Bang 
B)  500,000 years after the start of the Big Bang 
C)  3 minutes after the start of the Big Bang 
D)  3000 years after the start of the Big Bang 
A)  1/1,000,000 seconds after the start of the Big Bang 
B)  500,000 years after the start of the Big Bang 
C)  3 minutes after the start of the Big Bang 
D)  3000 years after the start of the Big Bang

Question 14

What is an advantage of quintessence over the cosmological constant as a description of dark energy?

Accepted Answer

A)  Einstein's reasoning in rejecting the cosmological constant still seems to be true today. 
B)  The cosmological constant would have to have, from the beginning of the universe, the right value to give a flat universe now: an amazing coincidence. The quintessence model does not have this requirement. 
C)  Quintessence is a well-established concept in physics, going back to ancient times, whereas the cosmological constant is a relatively new and untested concept. 
D)  The quintessence model predicts the correct age for the universe; the cosmological constant does not. 
A)  Einstein's reasoning in rejecting the cosmological constant still seems to be true today. 
B)  The cosmological constant would have to have, from the beginning of the universe, the right value to give a flat universe now: an amazing coincidence. The quintessence model does not have this requirement. 
C)  Quintessence is a well-established concept in physics, going back to ancient times, whereas the cosmological constant is a relatively new and untested concept. 
D)  The quintessence model predicts the correct age for the universe; the cosmological constant does not.

Question 15

Penzias and Wilson had no difficulty making their initial observation of the cosmic microwave background radiation at a wavelength of 7.35 millimeters.But it required other telescopes to verify the complete blackbody spectrum of the radiation.Why? (See Figure 14-4,Comins,Discovering the Essential Universe,6th ed.)

Accepted Answer

A)  The microwave receiver of Penzias and Wilson could be pointed at only one region of the sky, and a complete sky scan was necessary for the full blackbody curve. 
B)  Penzias and Wilson had, by coincidence, been observing the curve near its peak, where the intensity was strongest. The rest of the curve required more sensitive receivers. 
C)  The peak of the curve and the sharp fall-off on the short wavelength side occur at wavelengths of 1 millimeter or shorter, and this radiation is blocked by Earth's atmosphere. Thus, balloons and satellites had to be used. 
D)  Because of the changing seasons, the source of this radiation moved out of the night sky for Penzias and Wilson soon after they made their initial observation, so further measurements had to be made by observers elsewhere on Earth. 
A)  The microwave receiver of Penzias and Wilson could be pointed at only one region of the sky, and a complete sky scan was necessary for the full blackbody curve. 
B)  Penzias and Wilson had, by coincidence, been observing the curve near its peak, where the intensity was strongest. The rest of the curve required more sensitive receivers. 
C)  The peak of the curve and the sharp fall-off on the short wavelength side occur at wavelengths of 1 millimeter or shorter, and this radiation is blocked by Earth's atmosphere. Thus, balloons and satellites had to be used. 
D)  Because of the changing seasons, the source of this radiation moved out of the night sky for Penzias and Wilson soon after they made their initial observation, so further measurements had to be made by observers elsewhere on Earth.

Question 16

The fact that matter exists today is evidence that matter particles outnumber antimatter particles in the universe.This imbalance was caused by:

Accepted Answer

A)  matter inflation. 
B)  symmetry breaking. 
C)  chirality. 
D)  the cosmic overshift. 
A)  matter inflation. 
B)  symmetry breaking. 
C)  chirality. 
D)  the cosmic overshift.

Question 17

The conditions in the early universe at the time matter became decoupled from radiation were (in terms of age t and equivalent temperature T):

Accepted Answer

A)  t = 2 × 10¹¹ years , T = 3 K 
B)  t = 3 minutes, T = 10⁷ K 
C)  t = 380,000 years, T = 3000 K 
D)  The universe was never radiation-dominated since matter has always dominated by generating the gravitational field into which the universe has expanded. 
A)  t = 2 × 10¹¹ years , T = 3 K 
B)  t = 3 minutes, T = 10⁷ K 
C)  t = 380,000 years, T = 3000 K 
D)  The universe was never radiation-dominated since matter has always dominated by generating the gravitational field into which the universe has expanded.

Question 18

What kind of curvature (geometry of space)does the universe have if it is just on the boundary between being open and being closed?

Accepted Answer

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

Question 19

At the start of the Big Bang,all the fundamental forces were unified and behaved like a single force.As the universe expanded and cooled during the Big Bang,which was the FIRST to become a separate force?

Accepted Answer

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

Question 20

What will happen if the universe is closed?

Accepted Answer

A)  The universe will expand past its maximum size, then fragment into mini-universes. 
B)  The universe will eventually fall back in on itself, heading toward a "Big Crunch." 
C)  The universe will expand forever. 
D)  The universe will reach a maximum size and remain there, like a balloon being blown up. 
A)  The universe will expand past its maximum size, then fragment into mini-universes. 
B)  The universe will eventually fall back in on itself, heading toward a "Big Crunch." 
C)  The universe will expand forever. 
D)  The universe will reach a maximum size and remain there, like a balloon being blown up.

Why would we expect the rate of expansion of the universe to be slowing down?

The Big Bang theory is the most widely accepted model of the early universe today.Which statement is NOT one of the reasons for this?

In modern particle physics,the proton and the neutron are now thought to be composed of more fundamental particles called:

What significant event occurred about 500,000 years after the start of the Big Bang?

Which scientist discovered that the equations he had derived predicted an expanding universe,then modified his equations to eliminate this expansion?

As currently understood,what happens to the density of matter and the density of dark energy as the universe expands?

Newton reached the conclusion that the universe must consist of an infinite expanse of stars because:

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

The cosmic background radiation is:

Physicists are attempting to develop a Theory of Everything.What would be unique about such a theory?

The four physical forces at work in the universe are gravitational,electromagnetic,strong nuclear,and weak nuclear forces.Which two of these are very short-ranged,extending over distances of only about 10-¹⁵ m?

When did the inflationary period begin?

What is an advantage of quintessence over the cosmological constant as a description of dark energy?

The fact that matter exists today is evidence that matter particles outnumber antimatter particles in the universe.This imbalance was caused by:

The conditions in the early universe at the time matter became decoupled from radiation were (in terms of age t and equivalent temperature T):

What kind of curvature (geometry of space)does the universe have if it is just on the boundary between being open and being closed?

At the start of the Big Bang,all the fundamental forces were unified and behaved like a single force.As the universe expanded and cooled during the Big Bang,which was the FIRST to become a separate force?

What will happen if the universe is closed?

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

Why would we expect the rate of expansion of the universe to be slowing down?

The Big Bang theory is the most widely accepted model of the early universe today.Which statement is NOT one of the reasons for this?

In modern particle physics,the proton and the neutron are now thought to be composed of more fundamental particles called:

What significant event occurred about 500,000 years after the start of the Big Bang?

Which scientist discovered that the equations he had derived predicted an expanding universe,then modified his equations to eliminate this expansion?

As currently understood,what happens to the density of matter and the density of dark energy as the universe expands?

Newton reached the conclusion that the universe must consist of an infinite expanse of stars because:

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

The cosmic background radiation is:

Physicists are attempting to develop a Theory of Everything.What would be unique about such a theory?

The four physical forces at work in the universe are gravitational,electromagnetic,strong nuclear,and weak nuclear forces.Which two of these are very short-ranged,extending over distances of only about 10-¹⁵ m?

When did the inflationary period begin?

What is an advantage of quintessence over the cosmological constant as a description of dark energy?

The fact that matter exists today is evidence that matter particles outnumber antimatter particles in the universe.This imbalance was caused by:

The conditions in the early universe at the time matter became decoupled from radiation were (in terms of age t and equivalent temperature T):

What kind of curvature (geometry of space)does the universe have if it is just on the boundary between being open and being closed?

At the start of the Big Bang,all the fundamental forces were unified and behaved like a single force.As the universe expanded and cooled during the Big Bang,which was the FIRST to become a separate force?

What will happen if the universe is closed?

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