Question 1

Will the Sun get larger over many billions of years?

Accepted Answer

A)  Yes, because of changes taking place in its interior. 
B)  Yes, because the rate of expansion of the universe is increasing. 
C)  No, because the Earth is at center of the universe's expansion. 
D)  Yes, because of the expansion of the universe is pulling the Sun apart. 
E)  No. It has always been the same size. 
A)  Yes, because of changes taking place in its interior. 
B)  Yes, because the rate of expansion of the universe is increasing. 
C)  No, because the Earth is at center of the universe's expansion. 
D)  Yes, because of the expansion of the universe is pulling the Sun apart. 
E)  No. It has always been the same size.

Question 2

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 3

Where in the universe did the Big Bang take place?

Accepted Answer

A)  near the Milky Way Galaxy 
B)  near the Virgo cluster 
C)  near some unknown location on the other side of the universe 
D)  everywhere in the universe 
E)  at the center of the universe, not too far from the center of the cosmic background radiation 
A)  near the Milky Way Galaxy 
B)  near the Virgo cluster 
C)  near some unknown location on the other side of the universe 
D)  everywhere in the universe 
E)  at the center of the universe, not too far from the center of the cosmic background radiation

Question 4

Name three "rungs" in the distance ladder that let us estimate the value of the Hubble constant.

Accepted Answer

Trigonometric parallax, period

Question 5

When we measure distances to very faint galaxies with Type I supernovae, the accuracy of the measurement is only as good as that of the calibration of Cepheid stars.

Accepted Answer

A) True 
 B)False

Question 6

Astronomers use galactic redshift as a measure of:

Accepted Answer

A)  gravity 
B)  luminosity 
C)  velocity 
D)  mass 
E)  distance 
A)  gravity 
B)  luminosity 
C)  velocity 
D)  mass 
E)  distance

Question 7

The abundance of various elements formed from Big Bang nucleosynthesis depended only on the temperature of normal matter in the early universe.

Accepted Answer

A) True 
 B)False

Question 8

The figure below shows the current measurements of the abundances of various light elements in the universe (vertical yellow bar), along with theoretical predictions. If you redetermined the abundance of ordinary helium (4He) and it was 90% of the current value, what would you conclude about the density of normal matter in today's universe?

Accepted Answer

A)  It would be higher, and all the various density indicators would agree. 
B)  It would be higher, but the various density indicators would disagree. 
C)  It would be lower, but the various density indicators would disagree about its value. 
D)  It would be lower, but the various density indicators would agree. 
E)  It would be about the same as current observations suggest. 
A)  It would be higher, and all the various density indicators would agree. 
B)  It would be higher, but the various density indicators would disagree. 
C)  It would be lower, but the various density indicators would disagree about its value. 
D)  It would be lower, but the various density indicators would agree. 
E)  It would be about the same as current observations suggest.

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

We can measure the value of H0 directly with no intermediate steps.

Accepted Answer

A) True 
 B)False

Question 11

In the Great Debate of 1920, Curtis and Shapley argued over whether or not:

Accepted Answer

A)  the Big Bang occurred 
B)  the age of the universe was 14 billion years 
C)  the universe was contracting 
D)  life existed outside of Earth 
E)  the spiral nebulae were located outside the Milky Way 
A)  the Big Bang occurred 
B)  the age of the universe was 14 billion years 
C)  the universe was contracting 
D)  life existed outside of Earth 
E)  the spiral nebulae were located outside the Milky Way

Question 12

Which of the following lists distance indicators that are used to measure distances ranging from the very nearest to the very farthest?

Accepted Answer

A)  Cepheids, parallax, main-sequence fitting, Type I supernovae 
B)  parallax, main-sequence fitting, Cepheids, Type I supernovae 
C)  parallax, main-sequence fitting, Type I supernovae, Cepheids 
D)  main-sequence fitting, parallax, Cepheids, Type I supernovae 
E)  Cepheids, Type I supernovae, main-sequence fitting, parallax 
A)  Cepheids, parallax, main-sequence fitting, Type I supernovae 
B)  parallax, main-sequence fitting, Cepheids, Type I supernovae 
C)  parallax, main-sequence fitting, Type I supernovae, Cepheids 
D)  main-sequence fitting, parallax, Cepheids, Type I supernovae 
E)  Cepheids, Type I supernovae, main-sequence fitting, parallax

Question 13

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

Accepted Answer

A) True 
 B)False

Question 14

If you measured the distances and recessional velocities for a sample of galaxies and plotted the data to get the figure below, what value would you derive for the Hubble constant?

Accepted Answer

A)  10 km/s/Mpc 
B)  50 km/s/Mpc 
C)  70 km/s/Mpc 
D)  100 km/s/Mpc 
E)  500 km/s/Mpc 
A)  10 km/s/Mpc 
B)  50 km/s/Mpc 
C)  70 km/s/Mpc 
D)  100 km/s/Mpc 
E)  500 km/s/Mpc

Question 15

You see a galaxy in which the H$\alpha$ 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 16

The current temperature of the cosmic microwave background radiation is 17 K.

Accepted Answer

A) True 
 B)False

Question 17

The temperature of the CMB is hotter on one side of the sky than on the other by approximately 3 mK. What does this tell us?

Accepted Answer

A)  The Earth has a peculiar velocity of about 8,000 km/s with respect to the CMB. 
B)  The Earth has a peculiar velocity of about 400 km/s with respect to the CMB. 
C)  The Earth is near the center of the universe's expansion, but not exactly at the middle. 
D)  The universe is expanding faster on one side of us than the other. 
E)  The universe is homogeneous but not isotropic. 
A)  The Earth has a peculiar velocity of about 8,000 km/s with respect to the CMB. 
B)  The Earth has a peculiar velocity of about 400 km/s with respect to the CMB. 
C)  The Earth is near the center of the universe's expansion, but not exactly at the middle. 
D)  The universe is expanding faster on one side of us than the other. 
E)  The universe is homogeneous but not isotropic.

Question 18

The CMB is a snapshot of the radiation in the universe at a redshift of z $\approx$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 19

If a galaxy has an apparent velocity of 700 km/s, what is its distance if the Hubble constant is 70 km/s/Mpc?

Accepted Answer

A)  10 Mpc 
B)  70 Mpc 
C)  100 Mpc 
D)  700 Mpc 
E)  1,000 Mpc 
A)  10 Mpc 
B)  70 Mpc 
C)  100 Mpc 
D)  700 Mpc 
E)  1,000 Mpc

Question 20

Galaxies move away from us in all directions because:

Accepted Answer

A)  the force of gravity increases with distance 
B)  the force of gravity weakens with distance 
C)  space is expanding 
D)  our galaxy has expelled all other galaxies 
E)  we are at the center of the expansion of the universe 
A)  the force of gravity increases with distance 
B)  the force of gravity weakens with distance 
C)  space is expanding 
D)  our galaxy has expelled all other galaxies 
E)  we are at the center of the expansion of the universe

Exam 19: The Expanding Universe

Will the Sun get larger over many billions of years?

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

Where in the universe did the Big Bang take place?

Name three "rungs" in the distance ladder that let us estimate the value of the Hubble constant.

When we measure distances to very faint galaxies with Type I supernovae, the accuracy of the measurement is only as good as that of the calibration of Cepheid stars.

Astronomers use galactic redshift as a measure of:

The abundance of various elements formed from Big Bang nucleosynthesis depended only on the temperature of normal matter in the early universe.

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?

We can measure the value of H0 directly with no intermediate steps.

In the Great Debate of 1920, Curtis and Shapley argued over whether or not:

Which of the following lists distance indicators that are used to measure distances ranging from the very nearest to the very farthest?

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

If you measured the distances and recessional velocities for a sample of galaxies and plotted the data to get the figure below, what value would you derive for the Hubble constant?

You see a galaxy in which the H α\alphaα 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?

The current temperature of the cosmic microwave background radiation is 17 K.

The temperature of the CMB is hotter on one side of the sky than on the other by approximately 3 mK. What does this tell us?

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

If a galaxy has an apparent velocity of 700 km/s, what is its distance if the Hubble constant is 70 km/s/Mpc?

Galaxies move away from us in all directions because:

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 Adornmentsmoons 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

We can measure the value of H₀ directly with no intermediate steps.

You see a galaxy in which the H $\alpha$ 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?

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