Question 1

The apparent recessional velocities of galaxies at large distances are due mainly to the actual motions of the galaxies through space.

Accepted Answer

A) True 
 B)False

Question 2

Is dark energy responsible for the expansion of the universe?

Accepted Answer

A) No.The expansion would happen without dark energy,but dark energy is causing the expansion rate to decrease. 
B) Yes.Dark energy is currently the driving force in the universe's expansion. 
C) No.Dark energy is only responsible for the observed rapid motions of stars within galaxies. 
D) No.The expansion would happen without dark energy,but dark energy is causing the expansion rate to increase. 
E) No.The dark energy has no effect on the expansion. 
A) No.The expansion would happen without dark energy,but dark energy is causing the expansion rate to decrease. 
B) Yes.Dark energy is currently the driving force in the universe's expansion. 
C) No.Dark energy is only responsible for the observed rapid motions of stars within galaxies. 
D) No.The expansion would happen without dark energy,but dark energy is causing the expansion rate to increase. 
E) No.The dark energy has no effect on the expansion.

Question 3

The Hubble Space Telescope can be used to study galaxies at a redshift equal to 2.How much has the universe expanded since that the light was emitted from these galaxies?

Accepted Answer

The expansion factor at z = 2

Question 4

The CMB is a snapshot of the radiation in the universe at a redshift of z ≈ 1,000 when the universe was:

Accepted Answer

A) 1,000 times smaller than it is today 
B) 10 times smaller than it is today 
C) two times smaller than it is today 
D) the same size as it is today 
E) 10 times larger than it is today 
A) 1,000 times smaller than it is today 
B) 10 times smaller than it is today 
C) two times smaller than it is today 
D) the same size as it is today 
E) 10 times larger than it is today

Question 5

Does the temperature of the cosmic background radiation tell us about the age of the universe?

Accepted Answer

A) Yes,since it was produced at a redshift of approximately 1,000. 
B) No,we still need to know the Hubble constant to know the universe's age. 
C) No,the temperature does not but the size of temperature variations in the CMB does tell us the age. 
D) Yes,in combination with information on cosmic nucleosynthesis. 
E) No,the CMB formed at a wide variety of times and gives no information on the age of the whole universe. 
A) Yes,since it was produced at a redshift of approximately 1,000. 
B) No,we still need to know the Hubble constant to know the universe's age. 
C) No,the temperature does not but the size of temperature variations in the CMB does tell us the age. 
D) Yes,in combination with information on cosmic nucleosynthesis. 
E) No,the CMB formed at a wide variety of times and gives no information on the age of the whole universe.

Question 6

What caused early astronomers to believe that our galaxy is only about 6,000 light-years across?

Accepted Answer

A) Telescopes were not powerful enough to observe stars farther away. 
B) Interstellar dust blocked visible light from stars farther away. 
C) Stars farther away could not be resolved as individual objects. 
D) Astronomers miscalculated the distances to stars,believing that the stars were 50 times closer than they actually were. 
E) Astronomers assumed all red stars were faint main-sequence stars,and they confused more luminous red giants with them. 
A) Telescopes were not powerful enough to observe stars farther away. 
B) Interstellar dust blocked visible light from stars farther away. 
C) Stars farther away could not be resolved as individual objects. 
D) Astronomers miscalculated the distances to stars,believing that the stars were 50 times closer than they actually were. 
E) Astronomers assumed all red stars were faint main-sequence stars,and they confused more luminous red giants with them.

Question 7

Does Hubble's law imply that our galaxy is sitting at the center of the universe? Explain.

Accepted Answer

Our galaxy is not at the center of the u

Question 8

What important event in the universe's history marked the creation of the cosmic background radiation?

Accepted Answer

The CMB is a relic of the time in the un

Question 9

Suppose the expansion of the whole universe began only about 2 billion years ago,and before that the universe was static and not expanding.What should we expect in such a situation?

Accepted Answer

A) We would see redshifts increasing with distance until a distance of approximately 2 billion light years. 
B) We would see a universe that was isotropic but not homogenous. 
C) Distant galaxies would be much smaller than our own,since they have not been expanding for 13 billion years. 
D) The cosmic microwave background would be perfectly uniform in temperature. 
E) We would not expect evidence for a Big Bang. 
A) We would see redshifts increasing with distance until a distance of approximately 2 billion light years. 
B) We would see a universe that was isotropic but not homogenous. 
C) Distant galaxies would be much smaller than our own,since they have not been expanding for 13 billion years. 
D) The cosmic microwave background would be perfectly uniform in temperature. 
E) We would not expect evidence for a Big Bang.

Question 10

What did Edwin Hubble study in the Andromeda Galaxy that proved it was an individual galaxy and not part of our own Milky Way?

Accepted Answer

A) Cepheid stars 
B) Type I supernovae 
C) globular clusters 
D) red giant stars 
E) RR Lyrae variables 
A) Cepheid stars 
B) Type I supernovae 
C) globular clusters 
D) red giant stars 
E) RR Lyrae variables

Question 11

If the distance of a galaxy is 10 Mpc,what is its recessional velocity if the Hubble constant is 70 km/s/Mpc?

Accepted Answer

A) 700 km/s 
B) 1,000 km/s 
C) 3,500 km/s 
D) 5,000 km/s 
E) 7,000 km/s 
A) 700 km/s 
B) 1,000 km/s 
C) 3,500 km/s 
D) 5,000 km/s 
E) 7,000 km/s

Question 12

As the universe expands,the sizes of galaxies expand a measurable amount as well.

Accepted Answer

A) True 
 B)False

Question 13

Name two predictions of the standard Big Bang theory that have been verified by observations.

Accepted Answer

The existence of cos

Question 14

The Sun is 27 percent helium by mass.Where was the majority of this helium manufactured?

Accepted Answer

A) in Type II supernovae explosions that happened before the Sun formed 
B) in low-mass stars that lived and died before the Sun formed 
C) in nuclear burning that happened in the Sun's core 
D) in the Big Bang 
E) by accreting Jupiter-mass planets in the early era of the Solar System 
A) in Type II supernovae explosions that happened before the Sun formed 
B) in low-mass stars that lived and died before the Sun formed 
C) in nuclear burning that happened in the Sun's core 
D) in the Big Bang 
E) by accreting Jupiter-mass planets in the early era of the Solar System

Question 15

Which of the following is NOT a prediction of the standard Big Bang theory that has been successfully verified by observations?

Accepted Answer

A) The universe is expanding. 
B) The most distant galaxies are redder because they are older. 
C) Helium and lithium were made as the universe cooled after the initial Big Bang. 
D) The early universe was very hot and dense. 
E) The most distant galaxies are redder because their light has been stretched during the time it took for the light to reach Earth. 
A) The universe is expanding. 
B) The most distant galaxies are redder because they are older. 
C) Helium and lithium were made as the universe cooled after the initial Big Bang. 
D) The early universe was very hot and dense. 
E) The most distant galaxies are redder because their light has been stretched during the time it took for the light to reach Earth.

Question 16

Does the expansion of the Universe make the Sun bigger? What about the Milky Way? Why or why not?

Accepted Answer

The expansion of the universe is only de

Question 17

The existence of the cosmic background radiation tells us that the early universe was:

Accepted Answer

A) much hotter than it is today 
B) much colder than it is today 
C) composed entirely of radiation at early times 
D) composed entirely of stars at early times 
E) about the same temperature as today,but was much more dense 
A) much hotter than it is today 
B) much colder than it is today 
C) composed entirely of radiation at early times 
D) composed entirely of stars at early times 
E) about the same temperature as today,but was much more dense

Question 18

The cosmological principle says physical laws that the universe is homogeneous and isotropic.

Accepted Answer

A) True 
 B)False

Question 19

You see a galaxy in which the Hα line (rest wavelength = 656.3 nm)is observed at a wavelength of 756.3 nm.What would be the observed wavelength of a particular helium line,which has a rest wavelength of 1,083 nm?

Accepted Answer

A) 1,083 nm 
B) 1,183 nm 
C) 1,248 nm 
D) 1,440 nm 
E) 3,142 nm 
A) 1,083 nm 
B) 1,183 nm 
C) 1,248 nm 
D) 1,440 nm 
E) 3,142 nm

Question 20

In an imaginary universe,astronomers find that there are thousands of galaxies within a few million light years,but beyond those galaxies there is nothing but empty space.Such a universe would be:

Accepted Answer

A) isotropic and homogeneous 
B) isotropic but not homogenous 
C) homogeneous but not isotropic 
D) neither homogeneous nor isotropic 
E) lacking any evidence for the Big Bang 
A) isotropic and homogeneous 
B) isotropic but not homogenous 
C) homogeneous but not isotropic 
D) neither homogeneous nor isotropic 
E) lacking any evidence for the Big Bang

Exam 19: The Expanding Universe

The apparent recessional velocities of galaxies at large distances are due mainly to the actual motions of the galaxies through space.

Is dark energy responsible for the expansion of the universe?

The Hubble Space Telescope can be used to study galaxies at a redshift equal to 2.How much has the universe expanded since that the light was emitted from these galaxies?

The CMB is a snapshot of the radiation in the universe at a redshift of z ≈ 1,000 when the universe was:

Does the temperature of the cosmic background radiation tell us about the age of the universe?

What caused early astronomers to believe that our galaxy is only about 6,000 light-years across?

Does Hubble's law imply that our galaxy is sitting at the center of the universe? Explain.

What important event in the universe's history marked the creation of the cosmic background radiation?

Suppose the expansion of the whole universe began only about 2 billion years ago,and before that the universe was static and not expanding.What should we expect in such a situation?

What did Edwin Hubble study in the Andromeda Galaxy that proved it was an individual galaxy and not part of our own Milky Way?

If the distance of a galaxy is 10 Mpc,what is its recessional velocity if the Hubble constant is 70 km/s/Mpc?

As the universe expands,the sizes of galaxies expand a measurable amount as well.

Name two predictions of the standard Big Bang theory that have been verified by observations.

The Sun is 27 percent helium by mass.Where was the majority of this helium manufactured?

Which of the following is NOT a prediction of the standard Big Bang theory that has been successfully verified by observations?

Does the expansion of the Universe make the Sun bigger? What about the Milky Way? Why or why not?

The existence of the cosmic background radiation tells us that the early universe was:

The cosmological principle says physical laws that the universe is homogeneous and isotropic.

You see a galaxy in which the Hα line (rest wavelength = 656.3 nm)is observed at a wavelength of 756.3 nm.What would be the observed wavelength of a particular helium line,which has a rest wavelength of 1,083 nm?

In an imaginary universe,astronomers find that there are thousands of galaxies within a few million light years,but beyond those galaxies there is nothing but empty space.Such a universe would be:

Why Learn Astronomy

Patterns in the Skymotions of Earth

Motion of Astronomical Bodies

Gravity and Orbits

Light

The Tools of the Astronomer

The Birth and Evolution of Planetary Systems

The Terrestrial Planets and Earths Moon

Atmospheres of the Terrestrial Planets

Worlds of Gas and Liquid the Giant Planets

Planetary Adornments Moons and Rings

Dwarf Planets and Small Solar System Bodies

Taking the Measure of Stars

Our Starthe Sun

Star Formation and the Interstellar Medium

Evolution of Low-Mass Stars

Evolution of High-Mass Stars

Relativity and Black Holes

Galaxies

The Milky Waya Normal Spiral Galaxy

Modern Cosmology

Large-Scale Structure in the Universe

Life

Filters