Question 1

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. C

Question 2

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 A

Question 3

If Ω mass + Ω Λ = 1 today and dark energy were a cosmological constant,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 A

Question 4

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 5

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 6

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 7

Which of the following is FALSE?

Accepted Answer

A) When the universe was young,matter worked to slow the expansion rate of the universe. 
B) The Big Bang occurred approximately 13.7 billion years ago. 
C) Only in the last 5 to 6 billion years has dark energy caused the universe's expansion rate to increase over time. 
D) Throughout the age of the universe,dark energy has caused its expansion rate to increase over time. 
E) Astrophysicists are unsure whether or not dark energy always will continue to increase the expansion rate of the universe. 
A) When the universe was young,matter worked to slow the expansion rate of the universe. 
B) The Big Bang occurred approximately 13.7 billion years ago. 
C) Only in the last 5 to 6 billion years has dark energy caused the universe's expansion rate to increase over time. 
D) Throughout the age of the universe,dark energy has caused its expansion rate to increase over time. 
E) Astrophysicists are unsure whether or not dark energy always will continue to increase the expansion rate of the universe.

Question 8

The force that binds three quarks together to make up a proton or neutron is called the weak force.

Accepted Answer

A) True 
 B)False

Question 9

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 10

The standard model of particle physics is incomplete because it leaves which question(s)unanswered?

Accepted Answer

A) Why do neutrinos have mass? 
B) Why is the strong nuclear force much stronger than the weak nuclear force? 
C) How is gravity related to the other three fundamental forces? 
D) How does gravity work over such long distances? 
E) all of the above 
A) Why do neutrinos have mass? 
B) Why is the strong nuclear force much stronger than the weak nuclear force? 
C) How is gravity related to the other three fundamental forces? 
D) How does gravity work over such long distances? 
E) all of the above

Question 11

What is the Planck era?

Accepted Answer

A) the earliest moments after the Big Bang 
B) a period when quantum mechanics is needed to describe spacetime in addition to particles 
C) the time period when a theory of everything (TO
E) is needed to understand the universe 
D) When spacetime can be described as a quantum mechanical "foam" rather than a smooth sheet 
E) all of the above 
A) the earliest moments after the Big Bang 
B) a period when quantum mechanics is needed to describe spacetime in addition to particles 
C) the time period when a theory of everything (TO
E) is needed to understand the universe 
D) When spacetime can be described as a quantum mechanical "foam" rather than a smooth sheet 
E) all of the above

Question 12

As the universe cooled shortly after the Big Bang,which was the first fundamental force to separate itself out from the others?

Accepted Answer

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

Question 13

The critical mass density of the universe today is 9.5 × 10−27 kg/m3.Using the current observed value of Ωluminous,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 Ω_luminous = 0.02 there the average density o

Question 14

In quantum electrodynamics (QED),what mediates the electromagnetic force between particles?

Accepted Answer

In QED,the electromagnetic for

Question 15

If the sum of the mass and energy density in the universe yields Ω < 1,then the universe will recollapse in a Big Crunch.

Accepted Answer

A) True 
 B)False

Question 16

How would astronomers describe the antiparticle of an electron?

Accepted Answer

A) It would have the same charge but opposite spin. 
B) It would have the same mass but opposite charge. 
C) It would have the opposite charge and higher mass. 
D) It would have the opposite spin and higher mass. 
E) It would have the opposite charge but same spin. 
A) It would have the same charge but opposite spin. 
B) It would have the same mass but opposite charge. 
C) It would have the opposite charge and higher mass. 
D) It would have the opposite spin and higher mass. 
E) It would have the opposite charge but same spin.

Question 17

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

Accepted Answer

A TOE can link all four fundam

Question 18

What do astronomers believe is currently having the largest effect on the change in the expansion rate of the present-day universe?

Accepted Answer

A) dark matter 
B) baryonic (normal)matter 
C) dark energy 
D) radiation pressure 
E) gravity 
A) dark matter 
B) baryonic (normal)matter 
C) dark energy 
D) radiation pressure 
E) gravity

Question 19

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 20

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

Exam 22: Modern Cosmology

Which of these is a restatement of the anthropic principle?

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

If Ω mass + Ω Λ = 1 today and dark energy were a cosmological constant,the universe would:

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:

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

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

Which of the following is FALSE?

The force that binds three quarks together to make up a proton or neutron is called the weak force.

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

The standard model of particle physics is incomplete because it leaves which question(s)unanswered?

What is the Planck era?

As the universe cooled shortly after the Big Bang,which was the first fundamental force to separate itself out from the others?

In quantum electrodynamics (QED),what mediates the electromagnetic force between particles?

If the sum of the mass and energy density in the universe yields Ω < 1,then the universe will recollapse in a Big Crunch.

How would astronomers describe the antiparticle of an electron?

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

What do astronomers believe is currently having the largest effect on the change in the expansion rate of the present-day universe?

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

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

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 Adornments Moons 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

If Ω _mass + Ω _Λ = 1 today and dark energy were a cosmological constant,the universe would: