Question 1

Why would it be very improbable for our universe to have $\Omega$m +$\Omega$$\bigwedge$= 0.9?

Accepted Answer

A)  It would quickly evolve to have a much different value of $\Omega$m + $\Omega$$\bigwedge$. 
B)  In order to exist, every universe must have $\Omega$m + $\Omega$$\bigwedge$  = 1. 
C)  We know $\Omega$m =1, based on the average density of galaxies. 
D)  The CMB fluctuations tell us that $\Omega$m+$\Omega$$\bigwedge$  = 0.7. 
E)  Dark energy studies tell us $\Omega$$\bigwedge$ = 0.9. 
A)  It would quickly evolve to have a much different value of $\Omega$m + $\Omega$$\bigwedge$. 
B)  In order to exist, every universe must have $\Omega$m + $\Omega$$\bigwedge$  = 1. 
C)  We know $\Omega$m =1, based on the average density of galaxies. 
D)  The CMB fluctuations tell us that $\Omega$m+$\Omega$$\bigwedge$  = 0.7. 
E)  Dark energy studies tell us $\Omega$$\bigwedge$ = 0.9. A

Question 2

The effect of matter on the universe is to

Accepted Answer

A)  amplify the effects of dark energy. 
B)  "smooth out" the shape of space at all scales. 
C)  accelerate expansion. 
D)  decelerate expansion. 
E)  do nothing, as mass has no effect on the large-scale universe at any time. 
A)  amplify the effects of dark energy. 
B)  "smooth out" the shape of space at all scales. 
C)  accelerate expansion. 
D)  decelerate expansion. 
E)  do nothing, as mass has no effect on the large-scale universe at any time. D

Question 3

If the fate of the universe were determined solely by what is currently known to be the total mass of the universe in luminous and dark matter (excluding dark energy), astronomers would predict that we live in a universe that will

Accepted Answer

A)  expand forever. 
B)  slow its expansion and eventually reach a steady state. 
C)  stop expanding and eventually collapse. 
D)  oscillate between expansion and collapse. 
E)  expand so quickly that it will rip apart. 
A)  expand forever. 
B)  slow its expansion and eventually reach a steady state. 
C)  stop expanding and eventually collapse. 
D)  oscillate between expansion and collapse. 
E)  expand so quickly that it will rip apart. A

Question 4

Choose the correct statement about inflation.

Accepted Answer

A)  It helps solve both the problems of the flatness of the universe and the smoothness of the cosmic background radiation. 
B)  It assumes that at some point in the future dark energy will decay and the universe will expand rapidly by a factor of 1030. 
C)  When the universe was approximately 1 second old, its size grew by a factor of 1030. 
D)  It is the best version for a TOE. 
E)  Scientists have obtained direct and undisputable observational evidence that inflation did occur. 
A)  It helps solve both the problems of the flatness of the universe and the smoothness of the cosmic background radiation. 
B)  It assumes that at some point in the future dark energy will decay and the universe will expand rapidly by a factor of 1030. 
C)  When the universe was approximately 1 second old, its size grew by a factor of 1030. 
D)  It is the best version for a TOE. 
E)  Scientists have obtained direct and undisputable observational evidence that inflation did occur.

Question 5

What can solve the flatness and horizon problem in cosmology, and why?

Accepted Answer

The concept of inflation in the very ear

Question 6

Explain why astronomers cannot accurately model the exact history of the universe in the first few fractions of a second after the Big Bang.

Accepted Answer

Very shortly after its burst into existe

Question 7

Current observations suggest that the density of all matter and the density of dark energy are

Accepted Answer

A)  ( $\Omega$m = 0.3 and  $\Omega$ $\bigwedge$ 0 =0.7, respectively.) 
B)  ( $\Omega$m = 0.02 and  $\Omega$ $\bigwedge$  = 0.5, respectively.) 
C)  ( $\Omega$m = 0.0 and  $\Omega$ $\bigwedge$  =0.9, respectively.) 
D)  ( $\Omega$m =0.7 and  $\Omega$ $\bigwedge$  =0.3, respectively.) 
E)  ( $\Omega$m = 0.02 and  $\Omega$ $\bigwedge$  = 0.0, respectively.) 
A)  ( $\Omega$m = 0.3 and  $\Omega$ $\bigwedge$ 0 =0.7, respectively.) 
B)  ( $\Omega$m = 0.02 and  $\Omega$ $\bigwedge$  = 0.5, respectively.) 
C)  ( $\Omega$m = 0.0 and  $\Omega$ $\bigwedge$  =0.9, respectively.) 
D)  ( $\Omega$m =0.7 and  $\Omega$ $\bigwedge$  =0.3, respectively.) 
E)  ( $\Omega$m = 0.02 and  $\Omega$ $\bigwedge$  = 0.0, respectively.)

Question 8

What fundamental force is responsible for holding the nucleons together inside atomic nuclei?

Accepted Answer

A)  electromagnetic 
B)  gravity 
C)  weak nuclear 
D)  dark energy 
E)  strong nuclear 
A)  electromagnetic 
B)  gravity 
C)  weak nuclear 
D)  dark energy 
E)  strong nuclear

Question 9

What particles are the carriers of the electromagnetic force?

Accepted Answer

A)  electrons 
B)  magnetic monopoles 
C)  gluons 
D)  photons 
E)  W + 
A)  electrons 
B)  magnetic monopoles 
C)  gluons 
D)  photons 
E)  W +

Question 10

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

Accepted Answer

A)  expand forever. 
B)  slow its expansion and eventually stop. 
C)  stop expanding and eventually collapse. 
D)  oscillate between expansion and collapse. 
E)  expand so quickly that it would be ripped apart. 
A)  expand forever. 
B)  slow its expansion and eventually stop. 
C)  stop expanding and eventually collapse. 
D)  oscillate between expansion and collapse. 
E)  expand so quickly that it would be ripped apart.

Question 11

Which fundamental force is responsible for radioactive beta decays?

Accepted Answer

A)  electromagnetic 
B)  gravity 
C)  weak nuclear 
D)  photons 
E)  strong nuclear 
A)  electromagnetic 
B)  gravity 
C)  weak nuclear 
D)  photons 
E)  strong nuclear

Question 12

If there were no dark energy in the universe, the value of ________ alone would determine the evolution and fate of the universe.

Accepted Answer

A)  H0 
B)  1/H0 
C)  G 
D)  ( $\Omega$m) 
E)  ( $\Omega$ $\bigwedge$ ) 
A)  H0 
B)  1/H0 
C)  G 
D)  ( $\Omega$m) 
E)  ( $\Omega$ $\bigwedge$ )

Question 13

Grand unified theories are very attractive because they can explain

Accepted Answer

A)  why we have five fundamental forces in the universe today. 
B)  why the Big Bang never made any antimatter. 
C)  why the universe consists mostly of matter. 
D)  the accelerating expansion of the universe. 
E)  what happens inside a black hole. 
A)  why we have five fundamental forces in the universe today. 
B)  why the Big Bang never made any antimatter. 
C)  why the universe consists mostly of matter. 
D)  the accelerating expansion of the universe. 
E)  what happens inside a black hole.

Question 14

The figure below shows five possible graphs of the scale factor of the universe as a function of time.Which of these graphs represent our universe, where  $\Omega$m = 0.3 and  $\Omega$  $\bigwedge$ =0.7?

Accepted Answer

A)  A 
B)  B 
C)  C 
D)  D 
E)  E 
A)  A 
B)  B 
C)  C 
D)  D 
E)  E

Question 15

The left panel of the figure below illustrates the classical view of the electric force, while the right panel illustrates the QED view.Explain the fundamental differences between these two views of the electromagnetic force.

Accepted Answer

In the classical view a proton produces

Question 16

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 17

The figure below shows a graph of the scale factor, RU, with time, for three different scenarios.The age of the universe is the difference between now and the time at which RU is zero. Which curve illustrates an accelerating universe?

Accepted Answer

A)  A 
B)  B 
C)  C 
D)  All of these curves are valid for an accelerating universe. 
E)  None of these curves is valid for an accelerating universe. 
A)  A 
B)  B 
C)  C 
D)  All of these curves are valid for an accelerating universe. 
E)  None of these curves is valid for an accelerating universe.

Question 18

Which of the four fundamental forces is the weakest?

Accepted Answer

A)  electromagnetic 
B)  gravity 
C)  weak nuclear 
D)  magnetic 
E)  strong nuclear 
A)  electromagnetic 
B)  gravity 
C)  weak nuclear 
D)  magnetic 
E)  strong nuclear

Question 19

Why does the production of electron-positron pairs require less-energetic photons than the production of proton-antiproton pairs?

Accepted Answer

The two photons involved in the creation

Question 20

The observations that show that the expansion of the universe is speeding up tell us the universe must contain

Accepted Answer

A)  gravity. 
B)  dark matter. 
C)  an effect opposing gravity. 
D)  black holes. 
E)  cosmic microwave background radiation. 
A)  gravity. 
B)  dark matter. 
C)  an effect opposing gravity. 
D)  black holes. 
E)  cosmic microwave background radiation.

Exam 22: Cosmology

Why would it be very improbable for our universe to have Ω\OmegaΩ m + Ω\OmegaΩ ⋀\bigwedge⋀ = 0.9?

The effect of matter on the universe is to

If the fate of the universe were determined solely by what is currently known to be the total mass of the universe in luminous and dark matter (excluding dark energy), astronomers would predict that we live in a universe that will

Choose the correct statement about inflation.

What can solve the flatness and horizon problem in cosmology, and why?

Explain why astronomers cannot accurately model the exact history of the universe in the first few fractions of a second after the Big Bang.

Current observations suggest that the density of all matter and the density of dark energy are

What fundamental force is responsible for holding the nucleons together inside atomic nuclei?

What particles are the carriers of the electromagnetic force?

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

Which fundamental force is responsible for radioactive beta decays?

If there were no dark energy in the universe, the value of ________ alone would determine the evolution and fate of the universe.

Grand unified theories are very attractive because they can explain

The figure below shows five possible graphs of the scale factor of the universe as a function of time.Which of these graphs represent our universe, where Ω\OmegaΩ m = 0.3 and Ω\OmegaΩ ⋀\bigwedge⋀ =0.7?

The left panel of the figure below illustrates the classical view of the electric force, while the right panel illustrates the QED view.Explain the fundamental differences between these two views of the electromagnetic force.

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

The figure below shows a graph of the scale factor, RU, with time, for three different scenarios.The age of the universe is the difference between now and the time at which RU is zero. Which curve illustrates an accelerating universe?

Which of the four fundamental forces is the weakest?

Why does the production of electron-positron pairs require less-energetic photons than the production of proton-antiproton pairs?

The observations that show that the expansion of the universe is speeding up tell us the universe must contain

Thinking Like an Astronomer

Patterns in the Skymotions of Earth and the Moon

Motion of Astronomical Bodies

Gravity and Orbits

Light

The Tools of the Astronomer

The Formation of Planetary Systems

The Terrestrial Planets and Earths Moon

Atmospheres of the Terrestrial Planets

Worlds of Gas and Liquidthe Giant Planets

Planetary Moons and Rings

Dwarf Planets and Small Solar System Bodies

Taking the Measure of Stars

Our Starthe Sun

The Interstellar Medium and Star Formation

Evolution of Low-Mass Stars

Evolution of High-Mass Stars

Relativity and Black Holes

Galaxies

The Milky Waya Normal Spiral Galaxy

The Expanding Universe

Large-Scale Structure in the Universe

Life

Filters

Why would it be very improbable for our universe to have $\Omega$ _m + $\Omega$ _$\bigwedge$= 0.9?

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

The figure below shows a graph of the scale factor, R_U, with time, for three different scenarios.The age of the universe is the difference between now and the time at which R_U is zero. Which curve illustrates an accelerating universe?