Question 1

What happened to the quarks that existed freely during the particle era?

Accepted Answer

A) They combined in groups to make protons,neutrons,and their antiparticles. 
B) They froze out of the soup of particles at the end of the era. 
C) They evaporated. 
D) They combined in groups to make electrons and neutrinos. 
E) They combined in groups to make W and Z bosons. 
A) They combined in groups to make protons,neutrons,and their antiparticles. 
B) They froze out of the soup of particles at the end of the era. 
C) They evaporated. 
D) They combined in groups to make electrons and neutrinos. 
E) They combined in groups to make W and Z bosons.

Question 2

Which statement about the cosmic microwave background is not true?

Accepted Answer

A) Its spectrum corresponds to a temperature of just under 3 degrees above absolute zero. 
B) With the exception of very small variations,it appears essentially the same in all directions in which we look into space. 
C) It is the result of a mixture of radiation from many independent sources,such as stars and galaxies. 
D) It is thought to be radiation that began its journey to our telescopes when the universe was about 380,000 years old. 
A) Its spectrum corresponds to a temperature of just under 3 degrees above absolute zero. 
B) With the exception of very small variations,it appears essentially the same in all directions in which we look into space. 
C) It is the result of a mixture of radiation from many independent sources,such as stars and galaxies. 
D) It is thought to be radiation that began its journey to our telescopes when the universe was about 380,000 years old.

Question 3

When we say that the electromagnetic and weak forces "freeze out" from the electroweak force at 10⁻¹⁰ seconds after the Big Bang,we mean that

Accepted Answer

A) these forces are important only at temperatures below the freezing point of water-a temperature that the universe reached at an age of about 10⁻¹⁰ second. 
B) "freezing out" was a term coined by particle physicists who think that the Big Bang theory is really cool. 
C) prior to this time the electromagnetic and weak forces maintained a single identity,but they possessed separate identities following this time. 
D) following this time neither the electromagnetic nor the weak force was ever important in the universe again. 
E) quantum fluctuations by high-speed,relativistic particles in a state of false vacuum cause disturbances in the spacetime continuum,leading to the process described in the question this answer refers to. 
A) these forces are important only at temperatures below the freezing point of water-a temperature that the universe reached at an age of about 10⁻¹⁰ second. 
B) "freezing out" was a term coined by particle physicists who think that the Big Bang theory is really cool. 
C) prior to this time the electromagnetic and weak forces maintained a single identity,but they possessed separate identities following this time. 
D) following this time neither the electromagnetic nor the weak force was ever important in the universe again. 
E) quantum fluctuations by high-speed,relativistic particles in a state of false vacuum cause disturbances in the spacetime continuum,leading to the process described in the question this answer refers to.

Question 4

Observations of the cosmic background radiation from the COBE satellite revealed tiny variations in its temperature from one place to another (corresponding to a few millionths of a degree Kelvin).

Accepted Answer

A) True 
 B)False

Question 5

What did COBE find regarding the smoothness of the cosmic background radiation?

Accepted Answer

COBE found that the cosmic background ra

Question 6

The four fundamental forces that operate in the universe today are

Accepted Answer

A) strong force,weak force,electromagnetic force,gravity. 
B) strong force,weak force,electric force,magnetic force. 
C) nuclear force,electromagnetic force,gravity,tidal force. 
D) nuclear force,gravity,electric force,magnetic force. 
A) strong force,weak force,electromagnetic force,gravity. 
B) strong force,weak force,electric force,magnetic force. 
C) nuclear force,electromagnetic force,gravity,tidal force. 
D) nuclear force,gravity,electric force,magnetic force.

Question 7

Refer to this scenario for the following questions:
Lost in Spacetime.Just when you thought it was safe to take final exams ...a vindictive multi-dimensional being reaches down (up? over? through?)to Earth and pulls you out of the universe.You are thrown back into the universe at a place of this being's choosing,and she permits you to leave only after you have identified your surroundings.You are subject to several tests.
Through a scientifically unexplainable miracle,you are able to survive in every one of the places you are tested.(Lest you become too comfortable,however,you certainly are able to feel any associated pain due to high temperature,pressure,gravity,etc. )In each case described below,identify your surroundings.In some cases,the surroundings described may exist only during eras of the universe (past or future)other than our own time;in those cases,you should identify both the place and the time where you are located.
-At last you are in a place where the heat and high density are no longer bothering you.However,although the density is very low,the gas around you is extremely high in temperature.In fact,the temperature is so high that it is emitting lots of X-rays,which are creating cancer-causing mutations in your body at a rapid rate.Well,at least the view is great! There are no stars anywhere within about 10,000 light-years of you,but at slightly greater distances your sky is brightened by many beautiful,star-filled structures,some with majestic spiral shapes.Where are you?

Accepted Answer

A) You are in the universe when it was about 200 million years old,just before galaxies began forming. 
B) You are in the center of the Milky Way Galaxy,looking outward into the Local Group. 
C) You are somewhere between the Andromeda and Milky Way galaxies in the Local Group. 
D) You are in intergalactic space within a rich cluster of thousands of galaxies. 
E) You are in the outskirts of a galaxy whose nucleus is a powerful quasar. 
A) You are in the universe when it was about 200 million years old,just before galaxies began forming. 
B) You are in the center of the Milky Way Galaxy,looking outward into the Local Group. 
C) You are somewhere between the Andromeda and Milky Way galaxies in the Local Group. 
D) You are in intergalactic space within a rich cluster of thousands of galaxies. 
E) You are in the outskirts of a galaxy whose nucleus is a powerful quasar.

Question 8

Helium originates from

Accepted Answer

A) stellar nucleosynthesis only. 
B) the Big Bang only. 
C) stellar nucleosynthesis with a small contribution from the Big Bang. 
D) the Big Bang with a small contribution from stellar nucleosynthesis. 
E) radioactive decay of heavier elements only. 
A) stellar nucleosynthesis only. 
B) the Big Bang only. 
C) stellar nucleosynthesis with a small contribution from the Big Bang. 
D) the Big Bang with a small contribution from stellar nucleosynthesis. 
E) radioactive decay of heavier elements only.

Question 9

What is Olbers' paradox and what is its resolution?

Accepted Answer

If the universe were infinite and unchan

Question 10

Briefly explain why radiation was trapped for 300,000 years during the era of nuclei,and why the cosmic background radiation broke free at the end of this era.

Accepted Answer

During the era of nuclei,the universe co

Question 11

What do we mean by inflation,and why might it have occurred at the end of the GUT era?

Accepted Answer

The inflation of the universe occurred o

Question 12

Laboratory experiments conducted with particle accelerators confirm predictions made by the theory that unifies

Accepted Answer

A) the electromagnetic and weak forces into the electroweak force. 
B) the strong,weak,and electromagnetic forces into the GUT force. 
C) the unification of all four forces into a single "superforce." 
D) the strong and weak forces into the combined nuclear force. 
A) the electromagnetic and weak forces into the electroweak force. 
B) the strong,weak,and electromagnetic forces into the GUT force. 
C) the unification of all four forces into a single "superforce." 
D) the strong and weak forces into the combined nuclear force.

Question 13

Why can't current theories describe what happened during the Planck era?

Accepted Answer

A) We do not know how hot or dense the universe was during that time. 
B) We do not understand the properties of antimatter. 
C) We do not yet have a theory that links quantum mechanics and general relativity. 
D) The Planck era was the time before the Big Bang,and we cannot describe what happened before that instant. 
A) We do not know how hot or dense the universe was during that time. 
B) We do not understand the properties of antimatter. 
C) We do not yet have a theory that links quantum mechanics and general relativity. 
D) The Planck era was the time before the Big Bang,and we cannot describe what happened before that instant.

Question 14

If observations had shown that the cosmic microwave background was perfectly smooth (rather than having very slight variations in temperature),then we would have no way to account for

Accepted Answer

A) the relationship between the strong and the weak force. 
B) the fact that our universe is expanding. 
C) how galaxies came to exist. 
D) the existence of helium in the universe. 
A) the relationship between the strong and the weak force. 
B) the fact that our universe is expanding. 
C) how galaxies came to exist. 
D) the existence of helium in the universe.

Question 15

Process of Science: Inflation can explain some general features of the Universe but it is not directly testable and cannot be considered a theory.

Accepted Answer

A) True 
 B)False

Question 16

What do we mean by inflation?

Accepted Answer

A) what happened the instant after the Big Bang 
B) a sudden expansion of the universe after the strong force froze out from the GUT force 
C) the expansion of the universe that we still observe today 
D) the sudden release of photons when a particle and antiparticle annihilate each other 
E) the separation that occurs after two photons collide and create a particle and an antiparticle 
A) what happened the instant after the Big Bang 
B) a sudden expansion of the universe after the strong force froze out from the GUT force 
C) the expansion of the universe that we still observe today 
D) the sudden release of photons when a particle and antiparticle annihilate each other 
E) the separation that occurs after two photons collide and create a particle and an antiparticle

Question 17

What is postulated to have caused a sudden inflation of the early universe?

Accepted Answer

A) the annihilation of matter and antimatter 
B) the separation of the electromagnetic and weak forces 
C) the "freezing out" of the strong force from the GUT force 
D) the energy released in the fusion of protons and neutrons to produce helium 
E) giant quantum fluctuations 
A) the annihilation of matter and antimatter 
B) the separation of the electromagnetic and weak forces 
C) the "freezing out" of the strong force from the GUT force 
D) the energy released in the fusion of protons and neutrons to produce helium 
E) giant quantum fluctuations

Question 18

Which of the following is not an observed characteristic of the cosmic microwave background?

Accepted Answer

A) It has a perfect thermal radiation spectrum. 
B) Its temperature is the same everywhere,except for small variations at the level of 1 part in 100,000. 
C) Its temperature is a little less than 3 Kelvin (3 degrees above absolute zero). 
D) It contains prominent spectral lines of hydrogen,the primary chemical ingredient of the universe. 
A) It has a perfect thermal radiation spectrum. 
B) Its temperature is the same everywhere,except for small variations at the level of 1 part in 100,000. 
C) Its temperature is a little less than 3 Kelvin (3 degrees above absolute zero). 
D) It contains prominent spectral lines of hydrogen,the primary chemical ingredient of the universe.

Question 19

According to the Big Bang theory,why do we live in a universe that is made of almost entirely of matter rather than antimatter?

Accepted Answer

A) During the first 0.001 second after the Big Bang,particles and antiparticles were made in almost but not perfectly equal numbers.Everything annihilated except the very slight excess of matter particles. 
B) GUT theories predict that under the conditions that prevailed in the early universe,the normal laws of physics would have been suspended so that only matter particles were created,and no particles of antimatter. 
C) The fact that we live in a universe made of matter is not surprising,because antimatter has never been shown to exist for real. 
D) Einstein's famous equation E = mc² tells us that energy can turn into matter,but does not tell us that it can turn into antimatter. 
A) During the first 0.001 second after the Big Bang,particles and antiparticles were made in almost but not perfectly equal numbers.Everything annihilated except the very slight excess of matter particles. 
B) GUT theories predict that under the conditions that prevailed in the early universe,the normal laws of physics would have been suspended so that only matter particles were created,and no particles of antimatter. 
C) The fact that we live in a universe made of matter is not surprising,because antimatter has never been shown to exist for real. 
D) Einstein's famous equation E = mc² tells us that energy can turn into matter,but does not tell us that it can turn into antimatter.

Question 20

GUT theories predict that protons will eventually decay,causing all solid objects in the universe to fall apart if the universe keeps expanding forever.

Accepted Answer

A) True 
 B)False

Exam 22: The Birth of the Universe

What happened to the quarks that existed freely during the particle era?

Which statement about the cosmic microwave background is not true?

When we say that the electromagnetic and weak forces "freeze out" from the electroweak force at 10⁻¹⁰ seconds after the Big Bang,we mean that

Observations of the cosmic background radiation from the COBE satellite revealed tiny variations in its temperature from one place to another (corresponding to a few millionths of a degree Kelvin).

What did COBE find regarding the smoothness of the cosmic background radiation?

The four fundamental forces that operate in the universe today are

Helium originates from

What is Olbers' paradox and what is its resolution?

Briefly explain why radiation was trapped for 300,000 years during the era of nuclei,and why the cosmic background radiation broke free at the end of this era.

What do we mean by inflation,and why might it have occurred at the end of the GUT era?

Laboratory experiments conducted with particle accelerators confirm predictions made by the theory that unifies

Why can't current theories describe what happened during the Planck era?

If observations had shown that the cosmic microwave background was perfectly smooth (rather than having very slight variations in temperature),then we would have no way to account for

Process of Science: Inflation can explain some general features of the Universe but it is not directly testable and cannot be considered a theory.

What do we mean by inflation?

What is postulated to have caused a sudden inflation of the early universe?

Which of the following is not an observed characteristic of the cosmic microwave background?

According to the Big Bang theory,why do we live in a universe that is made of almost entirely of matter rather than antimatter?

GUT theories predict that protons will eventually decay,causing all solid objects in the universe to fall apart if the universe keeps expanding forever.

A Modern View of the Universe

Discovering the Universe for Yourself

The Science of Astronomy

Making Sense of the Universe: Understanding Motion, Energy, and Gravity

Light and Matter: Reading Messages from the Cosmos

Telescopes: Portals of Discovery

Our Planetary System

Formation of the Solar System

Planetary Geology: Earth and the Other Terrestrial Worlds

Planetary Atmospheres: Earth and the Other Terrestrial Worlds

Jovian Planet Systems

Asteroids, Comets, and Dwarf Planets: Their Nature, Orbits, and Impacts

Other Planetary Systems: The New Science of Distant Worlds

Our Star

Surveying the Stars

Star Birth

Star Stuff

The Bizarre Stellar Graveyard

Our Galaxy

Galaxies and the Foundations of Modern Cosmology

Galaxy Evolution

Dark Matter, Dark Energy, and the Fate of the Universe

Life in the Universe

Celestial Timekeeping and Navigation

Space and Time

Spacetime and Gravity

Building Blocks of the Universe

Filters