Question 1

Why did the era of nuclei end when the universe was about 380,000 years old?

Accepted Answer

A) All the free particles had combined to form the nuclei of atoms. 
B) The universe had expanded and cooled to a temperature of about 3,000 K,cool enough for stable,neutral atoms to form. 
C) Neutrinos and electrons were finally able to escape the plasma of the early universe and no longer heated the other particles. 
D) Photons were finally able to escape the plasma of the early universe and no longer heated the hydrogen and helium ions. 
E) No theory can explain this. 
A) All the free particles had combined to form the nuclei of atoms. 
B) The universe had expanded and cooled to a temperature of about 3,000 K,cool enough for stable,neutral atoms to form. 
C) Neutrinos and electrons were finally able to escape the plasma of the early universe and no longer heated the other particles. 
D) Photons were finally able to escape the plasma of the early universe and no longer heated the hydrogen and helium ions. 
E) No theory can explain this. B

Question 2

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,someplace fairly comfortable.Very weak gravity is holding you to the surface of the small object on which you sit.Your object is apparently moving away from a star,perhaps one that it orbits with a period of thousands of years.Around you,geysers are spouting gas into space.Looking back along the object's orbit,you see particles of dust that the geysers apparently blew off the object when it was nearer to the star that it is now leaving behind.You conclude that the geysers were recently much more active but are now settling down into a quiescent state that may last for millennia.You also soon realize that you are closer to home than you have been in all your previous journeys.Perhaps if you can somehow find a small rocket,a heat shield,and a good parachute,you can escape and head home for your final exam.Where are you?

Accepted Answer

A) You are on an asteroid near the center of a galaxy,heading in toward a massive black hole. 
B) You have been shrunk in size and are riding a grain of interstellar dust that is carrying you on an orbit about our very own Sun. 
C) You are riding a jet of gas from a quasar that is headed in the direction of an ordinary star. 
D) You are on comet Hale-Bopp,circa May 1997. 
E) You are at Disneyland on the Moon,riding the new "wild and wet" roller coaster. 
A) You are on an asteroid near the center of a galaxy,heading in toward a massive black hole. 
B) You have been shrunk in size and are riding a grain of interstellar dust that is carrying you on an orbit about our very own Sun. 
C) You are riding a jet of gas from a quasar that is headed in the direction of an ordinary star. 
D) You are on comet Hale-Bopp,circa May 1997. 
E) You are at Disneyland on the Moon,riding the new "wild and wet" roller coaster. D

Question 3

(From a science quiz that appeared in the weekly magazine The Economist. )Economic history is easier to write than the history of the universe.Nevertheless,most cosmologists now think that when the universe was formed in which of the following manners?

Accepted Answer

A) First there was a Big Bang,then inflation (of space)caused recession (of all matter,away from the Big Bang). 
B) First there was inflation,which caused the Big Bang,then recession. 
C) First there was a Big Bang.There has not been any inflation yet,but if it comes it will cause recession. 
A) First there was a Big Bang,then inflation (of space)caused recession (of all matter,away from the Big Bang). 
B) First there was inflation,which caused the Big Bang,then recession. 
C) First there was a Big Bang.There has not been any inflation yet,but if it comes it will cause recession. A

Question 4

Approximately how long did the era of nucleosynthesis last?

Accepted Answer

A) 10⁻¹⁰ second 
B) 0.001 second 
C) 5 seconds 
D) 5 minutes 
E) 5 years 
A) 10⁻¹⁰ second 
B) 0.001 second 
C) 5 seconds 
D) 5 minutes 
E) 5 years

Question 5

What kinds of atomic nuclei formed during the era of nucleosynthesis?

Accepted Answer

A) only hydrogen 
B) only helium 
C) hydrogen and helium and trace amounts of deuterium and lithium 
D) roughly equal amounts of each of the following: hydrogen,helium,deuterium and lithium 
E) nuclei of all the chemical elements 
A) only hydrogen 
B) only helium 
C) hydrogen and helium and trace amounts of deuterium and lithium 
D) roughly equal amounts of each of the following: hydrogen,helium,deuterium and lithium 
E) nuclei of all the chemical elements

Question 6

What was the significance of the end of the era of nucleosynthesis,when the universe was about 5 minutes old?

Accepted Answer

A) The proportions of dark matter and luminous matter had been determined. 
B) The basic chemical composition of the universe had been determined. 
C) It marks the time at which the first stars formed. 
D) It marks the time at which the expansion of the universe had settled down to its current rate. 
A) The proportions of dark matter and luminous matter had been determined. 
B) The basic chemical composition of the universe had been determined. 
C) It marks the time at which the first stars formed. 
D) It marks the time at which the expansion of the universe had settled down to its current rate.

Question 7

Where do the photons in the cosmic background radiation originate?

Accepted Answer

A) the moment of the Big Bang 
B) the end of the Planck era 
C) during the era of nucleosynthesis 
D) the end of the era of nuclei 
E) during the era of galaxy formation 
A) the moment of the Big Bang 
B) the end of the Planck era 
C) during the era of nucleosynthesis 
D) the end of the era of nuclei 
E) during the era of galaxy formation

Question 8

)Why is the era of nucleosynthesis so important in determining the chemical composition of the universe?

Accepted Answer

A) All the elements except hydrogen were produced after the era of nucleosynthesis. 
B) We can observe spectra from this era to determine what the primordial mix of the elements was at the beginning of the universe. 
C) Except for the small amount of matter produced later by stars,the chemical composition of the universe is the same now as at the end of the era of nucleosynthesis. 
D) We can study the processes that occurred during the era of nucleosynthesis to determine how most of the elements in the universe were created. 
E) By knowing how much matter was created during the era of nucleosynthesis,we can determine whether the universe is open or closed. 
A) All the elements except hydrogen were produced after the era of nucleosynthesis. 
B) We can observe spectra from this era to determine what the primordial mix of the elements was at the beginning of the universe. 
C) Except for the small amount of matter produced later by stars,the chemical composition of the universe is the same now as at the end of the era of nucleosynthesis. 
D) We can study the processes that occurred during the era of nucleosynthesis to determine how most of the elements in the universe were created. 
E) By knowing how much matter was created during the era of nucleosynthesis,we can determine whether the universe is open or closed.

Question 9

What do we mean by inflation?

Accepted Answer

A) the expansion of the universe that we still observe today 
B) the sudden release of photons when a particle and antiparticle annihilate one another 
C) a sudden and extremely rapid expansion of the universe that occurred in a tiny fraction of a second during the universe's first second of existence 
D) quantum fluctuations by high speed,relativistic particles in a state of false vacuum that caused disturbances in the space-time continuum leading to the process described in the question to which this answer refers 
A) the expansion of the universe that we still observe today 
B) the sudden release of photons when a particle and antiparticle annihilate one another 
C) a sudden and extremely rapid expansion of the universe that occurred in a tiny fraction of a second during the universe's first second of existence 
D) quantum fluctuations by high speed,relativistic particles in a state of false vacuum that caused disturbances in the space-time continuum leading to the process described in the question to which this answer refers

Question 10

What is meant by the microwave observations of the cosmic background radiation revealing the "genetic code" of the universe?

Accepted Answer

The latest microwave observations of the

Question 11

Olbers' paradox is an apparently simple question,but its resolution suggests that the universe is finite in age.What is the question?

Accepted Answer

A) What would it be like to ride on a beam of light? 
B) How many stars are in the universe? 
C) Can we measure the position and momentum of an electron at the same time? 
D) Why is the sky dark at night? 
A) What would it be like to ride on a beam of light? 
B) How many stars are in the universe? 
C) Can we measure the position and momentum of an electron at the same time? 
D) Why is the sky dark at night?

Question 12

Which of the following statements about the cosmic background radiation is not true?

Accepted Answer

A) It has a temperature of about 3 degrees K above absolute zero. 
B) It is the result of a mixture of radiation from many independent sources,such as stars and galaxies. 
C) It had a much higher temperature in the past. 
D) It was discovered by Penzias and Wilson in the early 1960s. 
E) It appears essentially the same in all directions (it is isotropic). 
A) It has a temperature of about 3 degrees K above absolute zero. 
B) It is the result of a mixture of radiation from many independent sources,such as stars and galaxies. 
C) It had a much higher temperature in the past. 
D) It was discovered by Penzias and Wilson in the early 1960s. 
E) It appears essentially the same in all directions (it is isotropic).

Question 13

Current measurements of the density of the universe support the prediction of the theory of inflation that the universe should be flat.

Accepted Answer

A) True 
 B)False

Question 14

How many forces operated in the universe during the GUT era?

Accepted Answer

A) one,what we call the "super force" 
B) two,gravity and the GUT force 
C) two,gravity and the electroweak force 
D) three,gravity,the strong force,and the electroweak force 
E) all of the above forces 
A) one,what we call the "super force" 
B) two,gravity and the GUT force 
C) two,gravity and the electroweak force 
D) three,gravity,the strong force,and the electroweak force 
E) all of the above forces

Question 15

Briefly describe one of the three quandaries that are solved by inflation;that is,describe either the structure problem,the smoothness problem,or the flatness problem.

Accepted Answer

Structure problem: The fact that there a

Question 16

Why didn't the Big Bang produce many heavier elements than helium?

Accepted Answer

By the time helium nuclei could exist in

Question 17

The Big Bang predicts that one in four atoms in the universe is helium.

Accepted Answer

A) True 
 B)False

Question 18

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.
-You are on the surface of an object,and you have a fairly clear view out into space.It might be very nice,except for one major drawback: You are very squashed.Also,light you observe from distant objects is apparently slightly blueshifted (compared to what it normally looks like).The surface of the object is composed primarily of carbon and oxygen,and the horizon distance is about the same as that on Earth.By observing the stellar background for a few weeks,you realize that there are several planets orbiting your object.Where are you?

Accepted Answer

A) You are on the surface of Earth. 
B) You are on the surface of a planet that is somewhat more massive than Earth. 
C) You are on the surface of a white dwarf. 
D) You are "on" an accretion disk around a black hole. 
E) You are on the surface of a neutron star. 
A) You are on the surface of Earth. 
B) You are on the surface of a planet that is somewhat more massive than Earth. 
C) You are on the surface of a white dwarf. 
D) You are "on" an accretion disk around a black hole. 
E) You are on the surface of a neutron star.

Question 19

Which of the following observations cannot be explained by the Big Bang theory unless we assume that an episode of inflation occurred?

Accepted Answer

A) the fact that the temperature of the cosmic microwave background is almost the same everywhere 
B) the fact that about 25% of the ordinary matter in the universe consists of helium 
C) the existence of the cosmic microwave background 
D) the fact that the universe is expanding 
A) the fact that the temperature of the cosmic microwave background is almost the same everywhere 
B) the fact that about 25% of the ordinary matter in the universe consists of helium 
C) the existence of the cosmic microwave background 
D) the fact that the universe is expanding

Question 20

Process of Science: Why do we test theories about the Big Bang using particle accelerators instead of just using bigger and bigger telescopes to look further back in time?

Accepted Answer

The Universe was so small and hot during

Exam 22: The Birth of the Universe

Why did the era of nuclei end when the universe was about 380,000 years old?

(From a science quiz that appeared in the weekly magazine The Economist. )Economic history is easier to write than the history of the universe.Nevertheless,most cosmologists now think that when the universe was formed in which of the following manners?

Approximately how long did the era of nucleosynthesis last?

What kinds of atomic nuclei formed during the era of nucleosynthesis?

What was the significance of the end of the era of nucleosynthesis,when the universe was about 5 minutes old?

Where do the photons in the cosmic background radiation originate?

)Why is the era of nucleosynthesis so important in determining the chemical composition of the universe?

What do we mean by inflation?

What is meant by the microwave observations of the cosmic background radiation revealing the "genetic code" of the universe?

Olbers' paradox is an apparently simple question,but its resolution suggests that the universe is finite in age.What is the question?

Which of the following statements about the cosmic background radiation is not true?

Current measurements of the density of the universe support the prediction of the theory of inflation that the universe should be flat.

How many forces operated in the universe during the GUT era?

Briefly describe one of the three quandaries that are solved by inflation;that is,describe either the structure problem,the smoothness problem,or the flatness problem.

Why didn't the Big Bang produce many heavier elements than helium?

The Big Bang predicts that one in four atoms in the universe is helium.

Which of the following observations cannot be explained by the Big Bang theory unless we assume that an episode of inflation occurred?

Process of Science: Why do we test theories about the Big Bang using particle accelerators instead of just using bigger and bigger telescopes to look further back in time?

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