Question 1

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 2

Refer to this scenario for the following questions:
A multi-dimensional being reaches down to Earth and pulls you out of the universe. You are then thrown back into the universe at a place and time of the being's choosing, and you are permitted to leave only after you have identified your surroundings. This process is repeated several times. Through a scientifically unexplainable miracle, you are able to survive in every one of the places that you find yourself. In each scenario below, identify your surroundings (and potentially your cosmic era) from among the choices given.
-As far as you look, there seems to be nothing at all. Even the nearest electron is light-years away. No matter how far you travel, you can find no solid matter, not even a single proton. It's as if all of the matter in the universe has disintegrated. You do, however, detect a few strong gravitational fields-probably due to supermassive black holes-at enormous distances from you. Where are you?

Accepted Answer

A)  You are in the Planck Era of the early universe. 
B)  You are in the universe when it is 10⁴⁰ years old. 
C)  You are in the universe when it is 10¹⁰⁰ years old. 
D)  You are in the central regions of a quasar. 
E)  You are in the GUT era of the early universe during the period of inflation. 
A)  You are in the Planck Era of the early universe. 
B)  You are in the universe when it is 10⁴⁰ years old. 
C)  You are in the universe when it is 10¹⁰⁰ years old. 
D)  You are in the central regions of a quasar. 
E)  You are in the GUT era of the early universe during the period of inflation.

Question 3

What direct evidence do we have that the weak and electromagnetic forces were once unified as a single force?

Accepted Answer

A)  The most advanced telescopes are able to see back to the GUT era in the universe. 
B)  Detectors on Earth have received photons and high-energy particles from the GUT era. 
C)  Temperatures in the center of the Sun can reproduce the conditions during the Electroweak era. 
D)  Particle accelerators on Earth can reach energies equivalent to the high temperatures of the Electroweak era and have produced particles predicted by the unified theory. 
E)  We have no direct evidence of such a unified force. 
A)  The most advanced telescopes are able to see back to the GUT era in the universe. 
B)  Detectors on Earth have received photons and high-energy particles from the GUT era. 
C)  Temperatures in the center of the Sun can reproduce the conditions during the Electroweak era. 
D)  Particle accelerators on Earth can reach energies equivalent to the high temperatures of the Electroweak era and have produced particles predicted by the unified theory. 
E)  We have no direct evidence of such a unified force.

Question 4

Based on observations of the cosmic microwave background, the overall composition of the universe is ________.

Accepted Answer

A)  100% ordinary (baryonic) matter 
B)  15% ordinary (baryonic) matter, 85% non-ordinary (nonbaryonic) dark matter 
C)  1% ordinary (baryonic) matter, 99% non-ordinary (nonbaryonic) dark matter 
D)  4% ordinary (baryonic) matter, 23% non-ordinary (nonbaryonic) dark matter, 73% dark energy 
A)  100% ordinary (baryonic) matter 
B)  15% ordinary (baryonic) matter, 85% non-ordinary (nonbaryonic) dark matter 
C)  1% ordinary (baryonic) matter, 99% non-ordinary (nonbaryonic) dark matter 
D)  4% ordinary (baryonic) matter, 23% non-ordinary (nonbaryonic) dark matter, 73% dark energy

Question 5

If inflation really occurred, then our observable universe is only a tiny portion of the entire universe born in the Big Bang.

Accepted Answer

A) True 
 B)False

Question 6

The Big Bang theory is supported by two major lines of evidence that alternative models have not successfully explained. What are they?

Accepted Answer

A)  (1) The theory predicts the existence of and the specific characteristics of the observed cosmic microwave background; (2) the theory correctly predicts the observed overall chemical composition of the universe. 
B)  (1) The theory correctly predicts that the universe should be expanding; (2) the theory predicts the existence of and the specific characteristics of the observed cosmic microwave background. 
C)  (1) The theory predicts the episode of inflation that we think occurred in the early universe; (2) the theory predicts the existence of large quantities of dark matter. 
D)  (1) The theory correctly predicts that the universe should be expanding; (2) the theory correctly predicts the observed ratio of spiral to elliptical galaxies in the universe. 
A)  (1) The theory predicts the existence of and the specific characteristics of the observed cosmic microwave background; (2) the theory correctly predicts the observed overall chemical composition of the universe. 
B)  (1) The theory correctly predicts that the universe should be expanding; (2) the theory predicts the existence of and the specific characteristics of the observed cosmic microwave background. 
C)  (1) The theory predicts the episode of inflation that we think occurred in the early universe; (2) the theory predicts the existence of large quantities of dark matter. 
D)  (1) The theory correctly predicts that the universe should be expanding; (2) the theory correctly predicts the observed ratio of spiral to elliptical galaxies in the universe.

Question 7

Measuring the amount of deuterium in the universe allows us to set a limit on ________.

Accepted Answer

A)  the density of ordinary (baryonic) matter the universe 
B)  the total amount of mass in the universe 
C)  the acceleration of the universe 
D)  the current age of the universe 
A)  the density of ordinary (baryonic) matter the universe 
B)  the total amount of mass in the universe 
C)  the acceleration of the universe 
D)  the current age of the universe

Question 8

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

Accepted Answer

The era of nucleosynthesis is important

Question 9

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 10

The idea of dark matter arose to explain gravitational effects observed in galaxies and clusters of galaxies. However, studies of the early universe (especially of the cosmic microwave background and of chemical abundances) also tell us something about dark matter. What do they tell us?

Accepted Answer

A)  They add further support to the idea that dark matter really exists and is made of non-ordinary (nonbaryonic) matter, such as WIMPs. 
B)  They do not support the conclusion that dark matter is the dominant form of matter in the universe. 
C)  They tell us that dark matter probably exists, but that it must be made of ordinary matter in the form of dim objects in galactic halos. 
D)  They tell us that dark matter was produced during the era of nuclei. 
A)  They add further support to the idea that dark matter really exists and is made of non-ordinary (nonbaryonic) matter, such as WIMPs. 
B)  They do not support the conclusion that dark matter is the dominant form of matter in the universe. 
C)  They tell us that dark matter probably exists, but that it must be made of ordinary matter in the form of dim objects in galactic halos. 
D)  They tell us that dark matter was produced during the era of nuclei.

Question 11

According to the Big Bang theory, how many forces-and which ones-operated in the universe during the GUT era?

Accepted Answer

A)  2 forces: gravity and a single force that later became the strong, weak, and electromagnetic forces 
B)  1 force that represented the unification of all four forces that operate today 
C)  3 forces: gravity, the strong force, and the electroweak force 
D)  2 forces: the strong force and the electroweak force 
A)  2 forces: gravity and a single force that later became the strong, weak, and electromagnetic forces 
B)  1 force that represented the unification of all four forces that operate today 
C)  3 forces: gravity, the strong force, and the electroweak force 
D)  2 forces: the strong force and the electroweak force

Question 12

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

Accepted Answer

A)  One: a single, symmetric "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 four of the known forces 
A)  One: a single, symmetric "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 four of the known forces

Question 13

A GUT (grand unified theory) refers to theories that

Accepted Answer

A)  unify all four forces. 
B)  unify gravity and the electromagnetic and weak forces. 
C)  unify gravity and the strong and weak forces. 
D)  unify the strong force and the electromagnetic and weak forces. 
E)  unify the electromagnetic and weak forces. 
A)  unify all four forces. 
B)  unify gravity and the electromagnetic and weak forces. 
C)  unify gravity and the strong and weak forces. 
D)  unify the strong force and the electromagnetic and weak forces. 
E)  unify the electromagnetic and weak forces.

Question 14

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

Accepted Answer

COBE found that the cosmic background ra

Question 15

The Big Bang predicts that the universe should be 25 percent hydrogen and 75 percent helium.

Accepted Answer

A) True 
 B)False

Question 16

The graph above shows 4 models for how the average distance between galaxies could change with time, from the past (left) to now (middle) to the future (right hand side). The graph also shows real data, based on studies of supernovae. Each black dot on the graph is for one supernova explosion. The data are plotted with dots and black lines that indicate the range of uncertainty of each individual measurement. Use this graph to answer the following questions about cosmological models for the expansion of the universe. (Note that the models are in the same order, from top to bottom, whether on the right hand side of the graph or the left hand side. For example the accelerating model is the top line on both sides of the graph. You should also have a handout with a better version of this graph.) Which model(s) predict that galaxies are getting farther apart NOW?

Accepted Answer

A)  Accelerating 
B)  Coasting 
C)  Critical 
D)  Recollapsing 
E)  All of them. F) None of them. 
A)  Accelerating 
B)  Coasting 
C)  Critical 
D)  Recollapsing 
E)  All of them. F) None of them.

Question 17

A postulated inflationary era in which the early universe expanded in size by a factor of 10³⁰ in approximately 10⁻³⁶ seconds is incompatible with the theory of relativity because the universe would have expanded faster than the speed of light.

Accepted Answer

A) True 
 B)False

Question 18

(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,

Accepted Answer

A)  first there was a Big Bang and then inflation (of space) which 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 and then inflation (of space) which 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.

Question 19

In stars, helium can sometimes be fused into carbon and heavier elements (in their final stages of life). Why didn't the same fusion processes produce carbon and heavier elements in the early universe?

Accepted Answer

A)  By the time stable helium nuclei had formed, the temperature and density had already dropped too low for helium fusion to occur. 
B)  Helium fusion occurred, but the carbon nuclei that were made were later destroyed by the intense radiation in the early universe. 
C)  Temperatures in the early universe were never above the roughly 100 million Kelvin required for helium fusion. 
D)  No one knows-this is one of the major mysteries in astronomy. 
A)  By the time stable helium nuclei had formed, the temperature and density had already dropped too low for helium fusion to occur. 
B)  Helium fusion occurred, but the carbon nuclei that were made were later destroyed by the intense radiation in the early universe. 
C)  Temperatures in the early universe were never above the roughly 100 million Kelvin required for helium fusion. 
D)  No one knows-this is one of the major mysteries in astronomy.

Question 20

From what cosmic epoch 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

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

What direct evidence do we have that the weak and electromagnetic forces were once unified as a single force?

Based on observations of the cosmic microwave background, the overall composition of the universe is ________.

If inflation really occurred, then our observable universe is only a tiny portion of the entire universe born in the Big Bang.

The Big Bang theory is supported by two major lines of evidence that alternative models have not successfully explained. What are they?

Measuring the amount of deuterium in the universe allows us to set a limit on ________.

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

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 ________.

The idea of dark matter arose to explain gravitational effects observed in galaxies and clusters of galaxies. However, studies of the early universe (especially of the cosmic microwave background and of chemical abundances) also tell us something about dark matter. What do they tell us?

According to the Big Bang theory, how many forces-and which ones-operated in the universe during the GUT era?

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

A GUT (grand unified theory) refers to theories that

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

The Big Bang predicts that the universe should be 25 percent hydrogen and 75 percent helium.

A postulated inflationary era in which the early universe expanded in size by a factor of 10³⁰ in approximately 10⁻³⁶ seconds is incompatible with the theory of relativity because the universe would have expanded faster than the speed of light.

(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 stars, helium can sometimes be fused into carbon and heavier elements (in their final stages of life). Why didn't the same fusion processes produce carbon and heavier elements in the early universe?

From what cosmic epoch do the photons in the cosmic background radiation originate?

Our Place in the Universe

Discovering the Universe for Yourself

The Science of Astronomy

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

Light: the Cosmic Messenger

Formation of Planetary Systems: Our Solar System and Beyond

Earth and the Terrestrial Worlds

Jovian Planet Systems

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

Our Star

Surveying the Stars

Star Stuff

Bizarre Stellar Graveyard

Our Galaxy

Galaxies and the Foundation of Modern Cosmology

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

Life in the Universe

Filters

Exam 17: The Beginning of Time

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

What direct evidence do we have that the weak and electromagnetic forces were once unified as a single force?

Based on observations of the cosmic microwave background, the overall composition of the universe is ________.

If inflation really occurred, then our observable universe is only a tiny portion of the entire universe born in the Big Bang.

The Big Bang theory is supported by two major lines of evidence that alternative models have not successfully explained. What are they?

Measuring the amount of deuterium in the universe allows us to set a limit on ________.

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

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 ________.

The idea of dark matter arose to explain gravitational effects observed in galaxies and clusters of galaxies. However, studies of the early universe (especially of the cosmic microwave background and of chemical abundances) also tell us something about dark matter. What do they tell us?

According to the Big Bang theory, how many forces-and which ones-operated in the universe during the GUT era?

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

A GUT (grand unified theory) refers to theories that

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

The Big Bang predicts that the universe should be 25 percent hydrogen and 75 percent helium.

A postulated inflationary era in which the early universe expanded in size by a factor of 10³⁰ in approximately 10⁻³⁶ seconds is incompatible with the theory of relativity because the universe would have expanded faster than the speed of light.

(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 stars, helium can sometimes be fused into carbon and heavier elements (in their final stages of life). Why didn't the same fusion processes produce carbon and heavier elements in the early universe?

From what cosmic epoch do the photons in the cosmic background radiation originate?

Our Place in the Universe

Discovering the Universe for Yourself

The Science of Astronomy

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

Light: the Cosmic Messenger

Formation of Planetary Systems: Our Solar System and Beyond

Earth and the Terrestrial Worlds

Jovian Planet Systems

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

Our Star

Surveying the Stars

Star Stuff

Bizarre Stellar Graveyard

Our Galaxy

Galaxies and the Foundation of Modern Cosmology

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

Life in the Universe

Filters