Question 1

Directly after the Big Bang, the universe was filled with a variety of charged particles, antiparticles, and photons.

Accepted Answer

A) True 
 B)False

Question 2

Figure 2
-Figure 2 shows a graph of the value of  $\Omega$mass as a function of time in a universe with no dark energy. The five different curves correspond to universes with slightly different values for  $\Omega$mass one second after the Big Bang. Which line corresponds to a universe with the smallest value of  $\Omega$mass one second after the Big Bang?

Accepted Answer

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

Question 3

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

Accepted Answer

A)  " $\Omega$luminous = 0.1,  $\Omega$mass = 0.3,  $\Omega$$\wedge$  = 0.7" 
B)  " $\Omega$ luminous =0.02,  $\Omega$ mass = 0.5,  $\Omega$ $\wedge$  =.5" 
C)  " $\Omega$ luminous =0,  $\Omega$ mass = 0.1,  $\Omega$ $\wedge$  = 0.9" 
D)  " $\Omega$ luminous =0.02,  $\Omega$ mass = 0.3,  $\Omega$ $\wedge$  = 0.7" 
E)  " $\Omega$ luminous = 0.1,  $\Omega$ mass = 0.2,  $\Omega$ $\wedge$  = 0.7" 
A)  " $\Omega$luminous = 0.1,  $\Omega$mass = 0.3,  $\Omega$$\wedge$  = 0.7" 
B)  " $\Omega$ luminous =0.02,  $\Omega$ mass = 0.5,  $\Omega$ $\wedge$  =.5" 
C)  " $\Omega$ luminous =0,  $\Omega$ mass = 0.1,  $\Omega$ $\wedge$  = 0.9" 
D)  " $\Omega$ luminous =0.02,  $\Omega$ mass = 0.3,  $\Omega$ $\wedge$  = 0.7" 
E)  " $\Omega$ luminous = 0.1,  $\Omega$ mass = 0.2,  $\Omega$ $\wedge$  = 0.7"

Question 4

A grand unified theory unites which forces?

Accepted Answer

A)  only electromagnetism, weak nuclear, and strong nuclear forces 
B)  only gravity and strong nuclear forces 
C)  only electromagnetism, gravity, and weak nuclear forces 
D)  only gravity and electromagnetism forces 
E)  all four known forces 
A)  only electromagnetism, weak nuclear, and strong nuclear forces 
B)  only gravity and strong nuclear forces 
C)  only electromagnetism, gravity, and weak nuclear forces 
D)  only gravity and electromagnetism forces 
E)  all four known forces

Question 5

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 6

In the superstring theory that successfully unites gravity and quantum mechanics, the universe must have 11 dimensions (10 spatial and 1 temporal).

Accepted Answer

A) True 
 B)False

Question 7

Figure 1
-Figure 1 shows five graphs of the scale factor of the universe as a function of time. Which of these graphs would occur for a universe with  $\Omega$ mass $\gt$ 1 and  $\Omega$ 1$\wedge$  = 0?

Accepted Answer

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

Question 8

If the fate of the universe were determined SOLELY by what we currently know 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 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 9

Observations of Type I supernovae in distant galaxies confirm that the expansion of the universe is decreasing over time.

Accepted Answer

A) True 
 B)False

Question 10

If dark energy is currently causing the expansion rate of the universe to increase with time, does this mean that you should worry that the Sun, the Earth, and your body itself are expanding? Why or why not?

Accepted Answer

Dark energy is indeed causing space to e

Question 11

According to superstring theory, how are different varieties of elementary particles similar? How do they differ?

Accepted Answer

In superstring theory, all ele

Question 12

What is the difference between a grand unified theory and a theory of everything?

Accepted Answer

A TOE can link all four fundam

Question 13

Astronomers have confirmed the Grand Unified Theory by observing that protons decay in laboratory experiments.

Accepted Answer

A) True 
 B)False

Question 14

The critical density of the universe is closest to:

Accepted Answer

A)  1 proton/m3 
B)  1 g/m3 
C)  1 kg/m3 
D)  1 MEarth/m3 
E)  1 M $\odot$ /m3 
A)  1 proton/m3 
B)  1 g/m3 
C)  1 kg/m3 
D)  1 MEarth/m3 
E)  1 M $\odot$ /m3

Question 15

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

Accepted Answer

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

Question 16

If there were enough mass to slow down the expansion rate of the universe, how 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. Is this what we observe in our universe?

Accepted Answer

If the universe were slowing down, it mu

Question 17

Soon after the Big Bang, we believe the four fundamental forces of nature were united into one superforce, and __________ was the first to split off from the others.

Accepted Answer

A)  the strong force 
B)  electromagnetism 
C)  the weak force 
D)  gravity 
E)  nucleosynthesis 
A)  the strong force 
B)  electromagnetism 
C)  the weak force 
D)  gravity 
E)  nucleosynthesis

Question 18

In a universe with an accelerating expansion rate, the actual age of the universe is __________ the Hubble time.

Accepted Answer

A)  larger than 
B)  smaller than 
C)  negligible compared to 
D)  the same as 
E)  independent of 
A)  larger than 
B)  smaller than 
C)  negligible compared to 
D)  the same as 
E)  independent of

Question 19

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

At the very moment of its creation, the

Question 20

If the Hubble constant were larger than it is, how would that change the measured age of the universe? Explain your answer.

Accepted Answer

If the Hubble constant were larger, then

Exam 22: Modern Cosmology

Directly after the Big Bang, the universe was filled with a variety of charged particles, antiparticles, and photons.

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

A grand unified theory unites which forces?

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?

In the superstring theory that successfully unites gravity and quantum mechanics, the universe must have 11 dimensions (10 spatial and 1 temporal).

Figure 1 -Figure 1 shows five graphs of the scale factor of the universe as a function of time. Which of these graphs would occur for a universe with Ω\OmegaΩ mass >\gt> 1 and Ω\OmegaΩ 1 ∧\wedge∧ = 0?

If the fate of the universe were determined SOLELY by what we currently know 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:

Observations of Type I supernovae in distant galaxies confirm that the expansion of the universe is decreasing over time.

If dark energy is currently causing the expansion rate of the universe to increase with time, does this mean that you should worry that the Sun, the Earth, and your body itself are expanding? Why or why not?

According to superstring theory, how are different varieties of elementary particles similar? How do they differ?

What is the difference between a grand unified theory and a theory of everything?

Astronomers have confirmed the Grand Unified Theory by observing that protons decay in laboratory experiments.

The critical density of the universe is closest to:

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

If there were enough mass to slow down the expansion rate of the universe, how 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. Is this what we observe in our universe?

Soon after the Big Bang, we believe the four fundamental forces of nature were united into one superforce, and __________ was the first to split off from the others.

In a universe with an accelerating expansion rate, the actual age of the universe is __________ the Hubble time.

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

If the Hubble constant were larger than it is, how would that change the measured age of the universe? Explain your answer.

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

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