Question 1

Explain why inflation could lead to an infinite number of multiverses inside our own universe.Are they likely to be similar to or different from our own universe?

Accepted Answer

Because inflation made the universe trem

Question 2

The universe can be infinite in size for which large-scale geometries?

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 3

What is basis for the idea of multiverses, and what evidence is there for the existence of multiverses?

Accepted Answer

If the cosmological principle does not h

Question 4

Why is the smoothness of the cosmic microwave background radiation (CMB) considered a problem?

Accepted Answer

A)  A smooth CMB implies that the expansion of the universe should be constant with time 
B)  Because a relatively smooth CMB implies the universe should be one gigantic galaxy, not many billions of billions of galaxies. 
C)  A universe this smooth should have matter spread out so evenly, that no stars or galaxies should be able to form. 
D)  Because two opposite sides of the universe could not have been in contact, and so should not have been able to reach similar temperatures. 
E)  A universe with a CMB this smooth should have ended in a Big Crunch by now. 
A)  A smooth CMB implies that the expansion of the universe should be constant with time 
B)  Because a relatively smooth CMB implies the universe should be one gigantic galaxy, not many billions of billions of galaxies. 
C)  A universe this smooth should have matter spread out so evenly, that no stars or galaxies should be able to form. 
D)  Because two opposite sides of the universe could not have been in contact, and so should not have been able to reach similar temperatures. 
E)  A universe with a CMB this smooth should have ended in a Big Crunch by now.

Question 5

Compared to an electron, the antiparticle of an electron has

Accepted Answer

A)  the same charge but negative mass. 
B)  the same mass but opposite charge. 
C)  opposite charge and higher mass. 
D)  the same charge and higher mass. 
E)  opposite charge and negative mass. 
A)  the same charge but negative mass. 
B)  the same mass but opposite charge. 
C)  opposite charge and higher mass. 
D)  the same charge and higher mass. 
E)  opposite charge and negative mass.

Question 6

In the very early universe, which of the following types of particles and antiparticles first stopped being spontaneously formed out of photons and why?

Accepted Answer

A)  protons and neutrons, because their formation requires a larger number of photons 
B)  electrons and positrons, because their formation requires a smaller number of photons 
C)  protons and antiprotons, because their formation requires higher-energy photons 
D)  electrons and neutrinos, because their formation requires lower-energy photons 
E)  Protons, antiprotons, electrons, and neutrinos stopped forming at the same time. 
A)  protons and neutrons, because their formation requires a larger number of photons 
B)  electrons and positrons, because their formation requires a smaller number of photons 
C)  protons and antiprotons, because their formation requires higher-energy photons 
D)  electrons and neutrinos, because their formation requires lower-energy photons 
E)  Protons, antiprotons, electrons, and neutrinos stopped forming at the same time.

Question 7

In a universe dominated by an accelerated expansion rate, the actual age of the universe is ________ the Hubble time.

Accepted Answer

A)  older than 
B)  younger than 
C)  negligible compared with 
D)  the same as 
E)  independent of 
A)  older than 
B)  younger than 
C)  negligible compared with 
D)  the same as 
E)  independent of

Question 8

Imagine that you lived in a universe where there is enough mass to slow the expansion rate of the universe.Would the Hubble constant measured using very distant galaxies be different from what is observed in galaxies that are closer to us? Explain your answer.

Accepted Answer

If the universe were slowing down,it mus

Question 9

The flatness problem arises because only a universe with a value of ________ can have that value forever and also contain matter.

Accepted Answer

A)  ($\Omega$m + $\Omega$ $\bigwedge$  =0) 
B)  ($\Omega$m +$\Omega$ $\bigwedge$  =1) 
C)  ($\Omega$m +$\Omega$ $\bigwedge$  = 0.7) 
D)  ($\Omega$m+$\Omega$ $\bigwedge$  =0.02) 
E)  ($\Omega$m =$\Omega$ $\bigwedge$  =0) 
A)  ($\Omega$m + $\Omega$ $\bigwedge$  =0) 
B)  ($\Omega$m +$\Omega$ $\bigwedge$  =1) 
C)  ($\Omega$m +$\Omega$ $\bigwedge$  = 0.7) 
D)  ($\Omega$m+$\Omega$ $\bigwedge$  =0.02) 
E)  ($\Omega$m =$\Omega$ $\bigwedge$  =0)

Question 10

In some particle physics theories, the universe must have more than three spatial dimensions, but we experience only three.Why would we not see the other spatial dimensions?

Accepted Answer

A)  The other nine spatial dimensions are too small to be noticeable. 
B)  The other seven spatial dimensions are tightly wrapped around each other and have not expanded. 
C)  The other seven spatial dimensions undergo inflation and flatten themselves out. 
D)  The other nine spatial dimensions wrap around each another and form the temporal dimension. 
E)  The other seven spatial dimensions are completely full of dark matter. 
A)  The other nine spatial dimensions are too small to be noticeable. 
B)  The other seven spatial dimensions are tightly wrapped around each other and have not expanded. 
C)  The other seven spatial dimensions undergo inflation and flatten themselves out. 
D)  The other nine spatial dimensions wrap around each another and form the temporal dimension. 
E)  The other seven spatial dimensions are completely full of dark matter.

Question 11

String theory is

Accepted Answer

A)  a confirmed fact. 
B)  the correct theory, but we don't fully understand it, like gravity. 
C)  currently untestable. 
D)  experimentally verified, but the theory does not fully explain the evidence. 
E)  pure science fiction, with no grounding in science or mathematics. 
A)  a confirmed fact. 
B)  the correct theory, but we don't fully understand it, like gravity. 
C)  currently untestable. 
D)  experimentally verified, but the theory does not fully explain the evidence. 
E)  pure science fiction, with no grounding in science or mathematics.

Question 12

In a universe with no dark energy, what will happen to the expansion of the universe in the future if (a)  $\Omega$m $\gt$ 1, (b)  $\Omega$m =1, and (c)  $\Omega$m   $\lt$ 1?

Accepted Answer

For each case: (a)The universe's expansi

Question 13

Which of the fundamental forces in nature have an infinite range of action?

Accepted Answer

A)  electromagnetic and gravity 
B)  strong nuclear and gravity 
C)  strong and weak nuclear 
D)  electromagnetic and strong nuclear 
E)  All four fundamental forces have an infinite range of action. 
A)  electromagnetic and gravity 
B)  strong nuclear and gravity 
C)  strong and weak nuclear 
D)  electromagnetic and strong nuclear 
E)  All four fundamental forces have an infinite range of action.

Question 14

In the string theory that could successfully unite 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)  eleven 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)  eleven dimensions (10 spatial and 1 temporal).

Question 15

Why does inflation not violate the fundamental rule that nothing can travel through space faster than the speed of light?

Accepted Answer

Although the inflation scenario proposes

Question 16

What would be the eventual state of the universe if the mass density  $\Omega$ =  $\Omega$0, and dark energy did not exist?

Accepted Answer

Given an infinite am

Question 17

Which of the curves in the figure shown below would best describe the scenario of a Big Rip for the universe?

Accepted Answer

A)  A 
B)  B 
C)  C 
D)  all three of them 
E)  none of them 
A)  A 
B)  B 
C)  C 
D)  all three of them 
E)  none of them

Question 18

What is the "flatness problem" in cosmology?

Accepted Answer

If the mass and energy density of the un

Question 19

How does the critical density, $\rho$c, depend on the observed value of the Hubble constant, H0?

Accepted Answer

The Hubble constant is a sort of measure

Question 20

Which list correctly orders objects from the first one to form after the Big Bang to the last one to form?

Accepted Answer

A)  neutral atoms, protons, nuclei 
B)  protons, nuclei, neutral atoms 
C)  nuclei, neutral atoms, protons 
D)  protons, neutral atoms, nuclei 
E)  nuclei, protons, neutral atoms 
A)  neutral atoms, protons, nuclei 
B)  protons, nuclei, neutral atoms 
C)  nuclei, neutral atoms, protons 
D)  protons, neutral atoms, nuclei 
E)  nuclei, protons, neutral atoms

Exam 22: Cosmology

Explain why inflation could lead to an infinite number of multiverses inside our own universe.Are they likely to be similar to or different from our own universe?

The universe can be infinite in size for which large-scale geometries?

What is basis for the idea of multiverses, and what evidence is there for the existence of multiverses?

Why is the smoothness of the cosmic microwave background radiation (CMB) considered a problem?

Compared to an electron, the antiparticle of an electron has

In the very early universe, which of the following types of particles and antiparticles first stopped being spontaneously formed out of photons and why?

In a universe dominated by an accelerated expansion rate, the actual age of the universe is ________ the Hubble time.

Imagine that you lived in a universe where there is enough mass to slow the expansion rate of the universe.Would the Hubble constant measured using very distant galaxies be different from what is observed in galaxies that are closer to us? Explain your answer.

The flatness problem arises because only a universe with a value of ________ can have that value forever and also contain matter.

In some particle physics theories, the universe must have more than three spatial dimensions, but we experience only three.Why would we not see the other spatial dimensions?

String theory is

In a universe with no dark energy, what will happen to the expansion of the universe in the future if (a) Ω\OmegaΩ m >\gt> 1, (b) Ω\OmegaΩ m =1, and (c) Ω\OmegaΩ m <\lt< 1?

Which of the fundamental forces in nature have an infinite range of action?

In the string theory that could successfully unite gravity and quantum mechanics, the universe must have

Why does inflation not violate the fundamental rule that nothing can travel through space faster than the speed of light?

What would be the eventual state of the universe if the mass density Ω\OmegaΩ = Ω\OmegaΩ 0, and dark energy did not exist?

Which of the curves in the figure shown below would best describe the scenario of a Big Rip for the universe?

What is the "flatness problem" in cosmology?

How does the critical density, ρ\rhoρ c, depend on the observed value of the Hubble constant, H0?

Which list correctly orders objects from the first one to form after the Big Bang to the last one to form?

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

In a universe with no dark energy, what will happen to the expansion of the universe in the future if (a) $\Omega$ _m $\gt$ 1, (b) $\Omega$ _m =1, and (c) $\Omega$ _m $\lt$ 1?

What would be the eventual state of the universe if the mass density $\Omega$ = $\Omega$ ₀, and dark energy did not exist?

How does the critical density, $\rho$ _c, depend on the observed value of the Hubble constant, H₀?