Question 1

Even with infinitely powerful telescopes, we can look back in time only until the time when

Accepted Answer

A)  galaxies first formed 
B)  hydrogen and helium formed 
C)  stars first formed 
D)  gravity split off from a superforce 
E)  recombination happened 
A)  galaxies first formed 
B)  hydrogen and helium formed 
C)  stars first formed 
D)  gravity split off from a superforce 
E)  recombination happened

Question 2

What are two observations that, when combined, tell us that the universe has$\Omega$mass + $\Omega$$\wedge$ = 1 and is flat?

Accepted Answer

Correct answers are any two pa

Question 3

How does the existence of dark energy affect the expansion of the universe?

Accepted Answer

A)  It is possible for the mass density of the universe to be below the critical density and still collapse. 
B)  It is possible for the mass density of the universe to be below the critical density and still expand forever. 
C)  It is impossible to have a collapsing universe, regardless of its density. 
D)  It is impossible to have an expanding universe, regardless of its density. 
E)  It is impossible for the mass density of the universe to be above the critical density and still expand forever. 
A)  It is possible for the mass density of the universe to be below the critical density and still collapse. 
B)  It is possible for the mass density of the universe to be below the critical density and still expand forever. 
C)  It is impossible to have a collapsing universe, regardless of its density. 
D)  It is impossible to have an expanding universe, regardless of its density. 
E)  It is impossible for the mass density of the universe to be above the critical density and still expand forever.

Question 4

The Big Rip could occur in a universe where the effect of __________ increases with time.

Accepted Answer

A)  quantum mechanics 
B)  luminous matter 
C)  dark energy 
D)  gravity 
E)  dark matter 
A)  quantum mechanics 
B)  luminous matter 
C)  dark energy 
D)  gravity 
E)  dark matter

Question 5

Which of the following are NOT considered carrier particles used to mediate forces between other particles?

Accepted Answer

A)  photons 
B)  gluons 
C)  gravitons 
D)  quarks 
E)  W+particles 
A)  photons 
B)  gluons 
C)  gravitons 
D)  quarks 
E)  W+particles

Question 6

What is the "flatness problem" in cosmology?

Accepted Answer

If the mass and energy density of the un

Question 7

In the 1990s, astronomers found that distant Type I supernova were __________ than they expected, leading them to conclude that __________.

Accepted Answer

A)  brighter; the universe's expansion rate was decreasing with time 
B)  brighter; the universe was finite in size 
C)  fainter; the universe's expansion rate has been increasing with time 
D)  fainter; the universe was infinite in size 
E)  fainter; the universe was finite in size 
A)  brighter; the universe's expansion rate was decreasing with time 
B)  brighter; the universe was finite in size 
C)  fainter; the universe's expansion rate has been increasing with time 
D)  fainter; the universe was infinite in size 
E)  fainter; the universe was finite in size

Question 8

Which of these is a restatement of the anthropic principle?

Accepted Answer

A)  Life evolves to create more complex species. 
B)  Any galaxy must have living things. 
C)  The values of physical constants must allow for our existence. 
D)  There must be other civilizations in the universe. 
E)  Dark energy will pull the universe apart. 
A)  Life evolves to create more complex species. 
B)  Any galaxy must have living things. 
C)  The values of physical constants must allow for our existence. 
D)  There must be other civilizations in the universe. 
E)  Dark energy will pull the universe apart.

Question 9

At what stage in the universe's history do we think the asymmetry between matter and antimatter was created?

Accepted Answer

A)  at the very moment the Big Bang occurred 
B)  around the time gravity separated out of the single superforce 
C)  around the time the strong force separated out of the grand unified theory 
D)  around the time the weak force and electromagnetism separated 
E)  around the time the electric and magnetic forces separated 
A)  at the very moment the Big Bang occurred 
B)  around the time gravity separated out of the single superforce 
C)  around the time the strong force separated out of the grand unified theory 
D)  around the time the weak force and electromagnetism separated 
E)  around the time the electric and magnetic forces separated

Question 10

Why does the overall mass and energy density of the universe decide its ultimate fate?

Accepted Answer

A)  The greater the density of the universe, the more black holes will form, which will devour surrounding material more quickly. 
B)  The greater the density of the universe, the more gravitationally bound the universe will be. 
C)  The greater the density of the universe, the more massive stars it will contain, and the faster it will evolve. 
D)  The greater the density of the universe, the more stars it will form over time and the longer the universe will last. 
E)  The greater the density of the universe, the more supernova will explode, forcing the universe to expand forever. 
A)  The greater the density of the universe, the more black holes will form, which will devour surrounding material more quickly. 
B)  The greater the density of the universe, the more gravitationally bound the universe will be. 
C)  The greater the density of the universe, the more massive stars it will contain, and the faster it will evolve. 
D)  The greater the density of the universe, the more stars it will form over time and the longer the universe will last. 
E)  The greater the density of the universe, the more supernova will explode, forcing the universe to expand forever.

Question 11

The universe can be infinite in size for which shapes of the universe?

Accepted Answer

A)  open 
B)  closed 
C)  flat 
D)  closed and flat 
E)  open and flat 
A)  open 
B)  closed 
C)  flat 
D)  closed and flat 
E)  open and flat

Question 12

What are the names of the two particles that mediate the electromagnetic force in quantum electrodynamics (QED) and the strong force in quantum chromodynamics (QCD)?

Accepted Answer

The photon is the particle tha

Question 13

In the superstring theory that successfully unites gravity and quantum mechanics, the universe must have:

Accepted Answer

A)  four dimensions (three spatial and one temporal) 
B)  six dimensions (three spatial and three temporal) 
C)  seven dimensions (six spatial and one temporal) 
D)  nine dimensions (eight spatial and one temporal) 
E)  11 dimensions (10 spatial and 1 temporal) 
A)  four dimensions (three spatial and one temporal) 
B)  six dimensions (three spatial and three temporal) 
C)  seven dimensions (six spatial and one temporal) 
D)  nine dimensions (eight spatial and one temporal) 
E)  11 dimensions (10 spatial and 1 temporal)

Question 14

The four fundamental forces of nature are gravity, electromagnetism, the weak force, and the strong force.

Accepted Answer

A) True 
 B)False

Question 15

If  $\Omega$ mass = 0.5 today and there were no dark energy, the universe would:

Accepted Answer

A)  expand forever 
B)  slow its expansion but never reverse it 
C)  stop expanding and eventually collapse 
D)  oscillate between expansion and collapse 
E)  expand so quickly that the universe is ripped apart 
A)  expand forever 
B)  slow its expansion but never reverse it 
C)  stop expanding and eventually collapse 
D)  oscillate between expansion and collapse 
E)  expand so quickly that the universe is ripped apart

Question 16

The critical mass density of the universe today is 9.5 *10-27 kg/m3. Using the current observed value of $\Omega$luminous, what is the average density of protons in the universe? If they were spread evenly throughout the universe, what would be their typical separation? Note that the typical separation between protons would be roughly equal to the cube root of the average volume occupied by one proton, and the mass of a proton is 1.7 * 10-27 kg.

Accepted Answer

The @#LAT-DLM&_luminous = 0.02 there the

Question 17

The weak force mediates the beta decay of neutrons into protons, electrons, and antineutrinos.

Accepted Answer

A) True 
 B)False

Question 18

Why does the critical mass density of the universe depend on the value of Hubble's constant, H0?

Accepted Answer

H₀ is an indication of how fast

Question 19

What would the universe be like if there were complete symmetry between matter and antimatter?

Accepted Answer

A)  It would look similar to our universe, but half of it would be composed of antimatter. 
B)  We would observe two universes, one an antimatter reflection of the other. 
C)  There would be no universe, because all of the matter and antimatter would have been annihilated. 
D)  There would be a universe, but it would be completely composed of photons from the CMB. 
E)  It would look similar to our universe, but the charges of all of the particles would be reversed. 
A)  It would look similar to our universe, but half of it would be composed of antimatter. 
B)  We would observe two universes, one an antimatter reflection of the other. 
C)  There would be no universe, because all of the matter and antimatter would have been annihilated. 
D)  There would be a universe, but it would be completely composed of photons from the CMB. 
E)  It would look similar to our universe, but the charges of all of the particles would be reversed.

Question 20

The figure below illustrates pair production in the early universe, with one particle labeled with a question mark.   What type of particle must this be?

Accepted Answer

A)  proton 
B)  electron 
C)  antiproton 
D)  positron 
E)  neutron 
A)  proton 
B)  electron 
C)  antiproton 
D)  positron 
E)  neutron

Exam 22: Modern Cosmology

Even with infinitely powerful telescopes, we can look back in time only until the time when

What are two observations that, when combined, tell us that the universe has Ω\OmegaΩ mass + Ω\OmegaΩ ∧\wedge∧ = 1 and is flat?

How does the existence of dark energy affect the expansion of the universe?

The Big Rip could occur in a universe where the effect of __________ increases with time.

Which of the following are NOT considered carrier particles used to mediate forces between other particles?

What is the "flatness problem" in cosmology?

In the 1990s, astronomers found that distant Type I supernova were __________ than they expected, leading them to conclude that __________.

Which of these is a restatement of the anthropic principle?

At what stage in the universe's history do we think the asymmetry between matter and antimatter was created?

Why does the overall mass and energy density of the universe decide its ultimate fate?

The universe can be infinite in size for which shapes of the universe?

What are the names of the two particles that mediate the electromagnetic force in quantum electrodynamics (QED) and the strong force in quantum chromodynamics (QCD)?

In the superstring theory that successfully unites gravity and quantum mechanics, the universe must have:

The four fundamental forces of nature are gravity, electromagnetism, the weak force, and the strong force.

If Ω\OmegaΩ mass = 0.5 today and there were no dark energy, the universe would:

The weak force mediates the beta decay of neutrons into protons, electrons, and antineutrinos.

Why does the critical mass density of the universe depend on the value of Hubble's constant, H0?

What would the universe be like if there were complete symmetry between matter and antimatter?

The figure below illustrates pair production in the early universe, with one particle labeled with a question mark. What type of particle must this 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 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

The Expanding Universe

Galaxies

The Milky Waya Normal Spiral Galaxy

Large-Scale Structure in the Universe

Life

Filters

What are two observations that, when combined, tell us that the universe has $\Omega$ _mass + $\Omega$ _$\wedge$ = 1 and is flat?

In the 1990s, astronomers found that distant Type I supernova were than they expected, leading them to conclude that .

If $\Omega$ _mass = 0.5 today and there were no dark energy, the universe would:

Why does the critical mass density of the universe depend on the value of Hubble's constant, H₀?