Question 1

The cosmic microwave background gives us a view of the universe when it was
A) 14 billion years old.
B) 3-5 minutes old.
C) 380,000 years old.
D) about 1 million years old.

Accepted Answer

The cosmic microwave background gives us a view of the universe when it was 380,000 years old. This is because at that time, the universe had cooled enough for hydrogen atoms to form, and the radiation from this era has been stretched and cooled over time to become the cosmic microwave background radiation that we can observe today.

Question 2

The four fundamental forces that operate in the universe today are ________.
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

Accepted Answer

The four fundamental forces that operate in the universe today are strong force, weak force, electromagnetic force, and gravity. Choice A is the only option that lists all four of these forces. Choice B lists electric and magnetic forces separately, but these are actually different aspects of the electromagnetic force. Choice C lists tidal force, which is not considered one of the fundamental forces. Choice D lists nuclear force, which encompasses both strong and weak forces, but does not include the electromagnetic force.

Question 3

Which of the following statements correctly summarizes the events in the early universe according to the Big Bang theory?
A) The universe began with the forces unified. During the first fraction of a second, the forces separated and there was a brief but important episode of inflation. Subatomic particles of both matter and antimatter then began to appear from the energy present in the universe. Most of the particles annihilated to make photons, but some became protons, neutrons, electrons, and neutrinos. The protons and neutrons underwent some fusion during the first three minutes, thereby determining the basic chemical composition of the universe.
B) An episode of what we call inflation initiated the event of the Big Bang. Once the Big Bang got underway, particles and forces began to appear one by one. The forces produced protons, which fused to make hydrogen and helium until the universe was about 380,000 years old. Then gravity began to act, turning the hydrogen and helium into galaxies.
C) Forces and various subatomic particles began to appear during the first second after the Big Bang. For reasons not understood, the particles were all made of ordinary matter and none were made of antimatter, thus explaining why we live in a universe made of matter. The particles underwent some fusion for the first 380,000 years after the Big Bang, at which time the first stars were born.
D) The Big Bang began with the initiation of what we call inflation, which gradually slowed to the current expansion rate of the universe. Forces came to exist for a different reason, having to do with quantum fluctuations in the space-time continuum. Particles came to exist as a result of cracks made when forces froze. Once there were particles, gravity brought them together to make stars, and the stars then turned the particles into hydrogen, helium, and other elements.

Accepted Answer

This option accurately describes the events of the early universe according to the Big Bang theory, including the initial unity of forces, inflation, particle-antiparticle annihilation, formation of protons, neutrons, electrons, and neutrinos, fusion of protons and neutrons, and determination of the basic chemical composition of the universe.

Question 4

Rank these times based on the wavelength of the peak intensity of the cosmic background radiation at those times, from shortest to longest. (Hint: consider how the temperature of the universe or the cosmic background radiation changed with time.)
A) Today, 1 million years after the Big Bang, 100 million years after the Big Bang
B) Today, 100 million years after the Big Bang, 1 million years after the Big Bang
C) 1 million years after the Big Bang, 100 million years after the Big Bang, today
D) 100 million years after the Big Bang, 1 million years after the Big Bang, today

Accepted Answer

The wavelength of the peak intensity of the cosmic background radiation is inversely proportional to the temperature of the universe. As the universe expands, it cools down, and the temperature decreases. Therefore, the peak intensity wavelength increases with time. Thus, the oldest the period is, the longer the wavelength is.

From the options given, it is clear that today is the modern period, and the wavelength is the longest. The temperature of the universe was the highest just after the Big Bang, which was approximately 13.8 billion years ago. As time progressed, the temperature dropped. Therefore, 1 million years after the Big Bang was warmer than 100 million years after the Big Bang. Thus, the wavelengths are shorter.

Option D is the best choice because it is arranged from the shortest wavelength to the longest wavelength. Thus, the correct order is 100 million years after the Big Bang, 1 million years after the Big Bang, and today.

Question 5

Which of the following claims cannot be proved or disproved by science?
A) The universe is about 14 billion years old.
B) The universe is about 2000 years old.
C) The universe was created by God.
D) The universe started out very hot.

Accepted Answer

Science cannot prove or disprove the existence of God or divine creation, as it is a metaphysical claim beyond empirical testing and observation.

Question 6

Which of the following hypothetical observations, if true, would disprove a prediction of the Big Bang theory? The discovery of
A) a galaxy with 30% helium abundance.
B) the temperature of the universe is only 2.73 K.
C) a galaxy with 10% helium abundance.
D) a galaxy moving toward us.
E) two galaxies, at the same distance, moving away with slightly different speeds.

Accepted Answer

The Big Bang theory predicts the primordial abundance of helium in the universe to be around 25%, so if a galaxy with only 10% helium abundance is discovered, it would contradict this prediction and disprove the theory. The other options do not necessarily contradict the predictions of the Big Bang theory.

Question 7

Early in the history of the universe, the universe was
A) hotter.
B) the same temperature it is now.
C) colder.

Accepted Answer

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Question 8

Which event in the history of the universe happened last?
A) The electroweak force separated into electromagnetic and weak nuclear forces.
B) Stable helium nuclei formed.
C) Neutral atoms formed.
D) The GUT force separated into the electroweak force and strong force.

Accepted Answer

Neutral atoms formed after the universe cooled down enough for electrons to combine with nuclei, allowing light to travel freely for the first time in cosmic history. This happened about 380,000 years after the Big Bang. The other events listed happened earlier in the history of the universe.

Question 9

Consider the data points together with the models in the graph of expansion models. Which model is most strongly supported by the data?
A) Critical
B) Accelerating
C) Recollapsing
D) Coasting

Accepted Answer

The data points show an increasing rate of expansion, which is consistent with the accelerating model. The other models do not match the observed trend.

Question 10

The more baryons there are in the universe (a higher density of baryonic matter), the lower the ratio of deuterium to hydrogen is. Therefore, if Harry measures a higher ratio of deuterium to hydrogen than Sally, Harry infers
A) the same density of baryons as Sally.
B) a lower density of baryons than Sally.
C) a higher density of baryons than Sally.

Accepted Answer

A higher ratio of deuterium to hydrogen implies a lower density of baryons in the universe. Therefore, if Harry measures a higher ratio of deuterium to hydrogen than Sally, Harry infers a lower density of baryons in the universe than Sally.

Question 11

Creation science claims that scientific evidence can and does prove God made the universe. Select the statement which does NOT identify a legitimate objection to this claim. (Recall the hallmarks of science.)
A) Scientists are not allowed to believe in God.
B) If "God did it" is the explanation for everything, then final exams in astronomy would be very simple (all answers would be the same!), and science experiments would be very easy to explain: but we wouldn't learn much about the natural world.
C) Science cannot prove (or disprove) the existence of a superpowerful, supernatural deity.
D) The statement that "God did it" cannot be falsified by science, and therefore it is not a statement that science can test.

Accepted Answer

The statement "Scientists are not allowed to believe in God" is not a legitimate objection to the claim that scientific evidence can prove God made the universe. Science does not dictate personal beliefs or religious affiliations of scientists. The other statements (B, C, and D) are all valid objections to the claim made by creation science, as they all point out the limitations of using religious beliefs to explain natural phenomena through scientific means.

Question 12

Comparing the following 4 models, which model predicts that galaxies had the largest separations in the past? (Use the graph of expansion models as a guide.)
A) Accelerating
B) Coasting
C) Critical
D) Recollapsing

Accepted Answer

The answer of Comparing the following 4 models, which model...

Question 13

What is the significance of the Planck time?
A) Before it, conditions were so extreme that our current understanding of physics is insufficient to predict what might have occurred.
B) It is the time at which inflation is thought to have occurred.
C) It is the time when the cosmic microwave background was released.
D) It is the amount of time required for two protons to fuse to make deuterium.

Accepted Answer

The Planck time is the shortest theoretical interval of time that can be measured or defined in the universe, roughly equal to 5.39 x 10^-44 seconds. Before this time, the universe was in a state of extreme density, heat, and energy, where our current understanding of physics is insufficient to predict what might have occurred. Therefore, the significance of the Planck time is that it represents a fundamental limit to our understanding of the early universe.

Question 14

A "GUT" (grand unified theory) refers to theories that ________.
A) unify the strong force with the electromagnetic and weak forces
B) unify gravity with the strong and weak forces
C) unify the electromagnetic and weak forces
D) unify all four forces together

Accepted Answer

A "GUT" (grand unified theory) aims to unify the strong force with the electromagnetic and weak forces, but not gravity.

Question 15

Why is the night sky is dark?
A) The universe has a physical edge, beyond which there is nothing.
B) The dust clouds in interstellar space block the light.
C) Dark matter obscures light from distant objects.
D) The universe is finite in age.

Accepted Answer

The night sky is dark because the universe is finite in age, meaning it has not existed forever. This is related to Olbers' Paradox, which states that if the universe were infinite, eternal, and uniformly filled with stars, the night sky would be bright. However, because the universe has a finite age, light from distant stars has not had enough time to reach us, resulting in a dark night sky.

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

Accepted Answer

All the models predict that galaxies are getting farther apart now, as they all show an increase in the average distance between galaxies from the past to the present.

Question 17

Consider the graph of expansion models. Which model(s) predicts that galaxies will eventually get closer together?
A) Accelerating
B) Coasting
C) Critical
D) Recollapsing
E) All of them. F) None of them.

Accepted Answer

The recollapsing model predicts that the expansion of the universe will eventually slow down and reverse, causing galaxies to get closer together and leading to a collapse of the universe. The other models (accelerating, coasting, and critical) do not predict a collapse, and instead suggest that the universe will continue to expand indefinitely.

Question 18

What happens when a particle of matter meets its corresponding antiparticle of antimatter?
A) The combined mass of the two particles is completely transformed into energy (photons).
B) They can form a complete atom.
C) They fuse to make a heavier particle.
D) The question makes no sense, since antimatter does not really exist.

Accepted Answer

When a particle of matter meets its corresponding antiparticle of antimatter, they annihilate each other and their combined mass is completely transformed into energy in the form of photons. This process is known as annihilation.

Question 19

Based on our current understanding of physics, we can understand the conditions that prevailed in the early universe as far back in time as about ________.
A) one ten-billionth of a second after the Big Bang
B) 380,000 years after the Big Bang
C) 10⁻⁴⁵ seconds after the Big Bang
D) 10 billion years ago

Accepted Answer

Our current understanding of physics, particularly the Standard Model and General Relativity, allows us to understand conditions as far back as one ten-billionth of a second after the Big Bang. Before this, the conditions are too extreme for our current theories to describe accurately.

Question 20

What do we mean by inflation?
A) 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
B) The expansion of the universe that we still observe today
C) The sudden release of photons when a particle and antiparticle annihilate one another
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

Accepted Answer

Inflation refers to the theory of a rapid exponential expansion of the universe that occurred within the first fraction of a second after the Big Bang.

Quiz 17: The Beginning of Time

The cosmic microwave background gives us a view of the universe when it was

The four fundamental forces that operate in the universe today are ________.

Which of the following statements correctly summarizes the events in the early universe according to the Big Bang theory?

Rank these times based on the wavelength of the peak intensity of the cosmic background radiation at those times, from shortest to longest. (Hint: consider how the temperature of the universe or the cosmic background radiation changed with time.)

Which of the following claims cannot be proved or disproved by science?

Which of the following hypothetical observations, if true, would disprove a prediction of the Big Bang theory? The discovery of

Early in the history of the universe, the universe was

Which event in the history of the universe happened last?

Consider the data points together with the models in the graph of expansion models. Which model is most strongly supported by the data?

The more baryons there are in the universe (a higher density of baryonic matter) , the lower the ratio of deuterium to hydrogen is. Therefore, if Harry measures a higher ratio of deuterium to hydrogen than Sally, Harry infers

Creation science claims that scientific evidence can and does prove God made the universe. Select the statement which does NOT identify a legitimate objection to this claim. (Recall the hallmarks of science.)

Comparing the following 4 models, which model predicts that galaxies had the largest separations in the past? (Use the graph of expansion models as a guide.)

What is the significance of the Planck time?

A "GUT" (grand unified theory) refers to theories that ________.

Why is the night sky is dark?

Consider the graph of expansion models. Which model(s) predicts that galaxies will eventually get closer together?

What happens when a particle of matter meets its corresponding antiparticle of antimatter?

Based on our current understanding of physics, we can understand the conditions that prevailed in the early universe as far back in time as about ________.

What do we mean by inflation?