Question 1

When is/was gravitational contraction an important energy generation mechanism for the Sun?

Accepted Answer

A) It was important when the Sun was forming from a shrinking interstellar cloud of gas. 
B) It is the primary energy generation mechanism in the Sun today. 
C) It has played a role throughout the Sun's history,but it was most important right after nuclear fusion began in the Sun's core. 
D) It is important during periods when the Sun is going from solar maximum to solar minimum. 
A) It was important when the Sun was forming from a shrinking interstellar cloud of gas. 
B) It is the primary energy generation mechanism in the Sun today. 
C) It has played a role throughout the Sun's history,but it was most important right after nuclear fusion began in the Sun's core. 
D) It is important during periods when the Sun is going from solar maximum to solar minimum.

Question 2

Why are neutrinos so difficult to detect?

Accepted Answer

A) They have a tendency to pass through just about any material without any interactions. 
B) They are extremely rare. 
C) They have no mass. 
D) No one knows: this is the essence of the "solar neutrino problem." 
A) They have a tendency to pass through just about any material without any interactions. 
B) They are extremely rare. 
C) They have no mass. 
D) No one knows: this is the essence of the "solar neutrino problem."

Question 3

Which of the following best describes the current status of our understanding of the solar neutrino problem?

Accepted Answer

A) Experimental evidence indicates that the problem is solved and the expected number of solar neutrinos are indeed being produced by the Sun. 
B) The problem arose only because experimental data were being misinterpreted;on re-examination,the old data showed that the expected number of neutrinos were being detected. 
C) We have learned that the Sun's interior undergoes fusion at a lower rate than we had expected,and that is why we had observed fewer neutrinos than expected. 
D) The solar neutrino problem remains as perplexing as ever,and indeed makes everything we think we know about stars suspect. 
A) Experimental evidence indicates that the problem is solved and the expected number of solar neutrinos are indeed being produced by the Sun. 
B) The problem arose only because experimental data were being misinterpreted;on re-examination,the old data showed that the expected number of neutrinos were being detected. 
C) We have learned that the Sun's interior undergoes fusion at a lower rate than we had expected,and that is why we had observed fewer neutrinos than expected. 
D) The solar neutrino problem remains as perplexing as ever,and indeed makes everything we think we know about stars suspect.

Question 4

In the late 1800s,Kelvin and Helmholtz suggested that the Sun stayed hot thanks to gravitational contraction.What was the major drawback of this idea?

Accepted Answer

A) It predicted that the Sun could last only about 25 million years,which is far less than the age of Earth. 
B) It predicted that the Sun would shrink noticeably as we watched it,and the Sun appears to be stable in size. 
C) It is physically impossible to generate heat simply by making a star shrink in size. 
D) It predicted that Earth would also shrink,which would make it impossible to have stable geology on our planet. 
E) It was proposed before Einstein's theory of general relativity and was therefore incorrect. 
A) It predicted that the Sun could last only about 25 million years,which is far less than the age of Earth. 
B) It predicted that the Sun would shrink noticeably as we watched it,and the Sun appears to be stable in size. 
C) It is physically impossible to generate heat simply by making a star shrink in size. 
D) It predicted that Earth would also shrink,which would make it impossible to have stable geology on our planet. 
E) It was proposed before Einstein's theory of general relativity and was therefore incorrect.

Question 5

From center outward,which of the following lists the "layers" of the Sun in the correct order?

Accepted Answer

A) core,radiation zone,convection zone,corona,chromosphere,photosphere 
B) core,convection zone,radiation zone,corona,chromosphere,photosphere 
C) core,radiation zone,convection zone,photosphere,chromosphere,corona 
D) core,corona,radiation zone,convection zone,photosphere,chromosphere 
A) core,radiation zone,convection zone,corona,chromosphere,photosphere 
B) core,convection zone,radiation zone,corona,chromosphere,photosphere 
C) core,radiation zone,convection zone,photosphere,chromosphere,corona 
D) core,corona,radiation zone,convection zone,photosphere,chromosphere

Question 6

How much mass does the Sun lose through nuclear fusion per second?

Accepted Answer

A) 4 tons 
B) 4 million tons 
C) 600 tons 
D) 600 million tons 
E) Nothing: mass is conserved. 
A) 4 tons 
B) 4 million tons 
C) 600 tons 
D) 600 million tons 
E) Nothing: mass is conserved.

Question 7

The Sun's surface,as we see it with our eyes,is called the

Accepted Answer

A) chromosphere. 
B) photosphere. 
C) corona. 
D) core. 
A) chromosphere. 
B) photosphere. 
C) corona. 
D) core.

Question 8

Every second,the Sun converts about 600 million tons of hydrogen into 596 million tons of helium.The remaining 4 million tons of mass is

Accepted Answer

A) ejected into space in a solar wind. 
B) ejected into space by solar flares. 
C) converted to an amount of energy equal to 4 million tons times the speed of light squared. 
D) reabsorbed as molecular hydrogen. 
A) ejected into space in a solar wind. 
B) ejected into space by solar flares. 
C) converted to an amount of energy equal to 4 million tons times the speed of light squared. 
D) reabsorbed as molecular hydrogen.

Question 9

The Sun's surface seethes and churns with a bubbling pattern.Why?

Accepted Answer

A) The Sun's surface is boiling. 
B) The churning gas is being stirred up by the strong solar wind. 
C) The churning is an illusion created by varying radiation,as the gas on the Sun's surface is actually quite still. 
D) We are seeing hot gas rising and cool gas falling due to the convection that occurs beneath the surface. 
A) The Sun's surface is boiling. 
B) The churning gas is being stirred up by the strong solar wind. 
C) The churning is an illusion created by varying radiation,as the gas on the Sun's surface is actually quite still. 
D) We are seeing hot gas rising and cool gas falling due to the convection that occurs beneath the surface.

Question 10

Briefly explain how the Sun became hot enough for nuclear fusion.

Accepted Answer

The Sun formed from a cloud of gas.As it

Question 11

Process of Science: Why is it important to understand the Sun in order to understand the Earth's radiation belts and space weather?

Accepted Answer

Solar activity causes the resp

Question 12

The proton-proton chain converts four hydrogen nuclei into one helium nucleus.

Accepted Answer

A) True 
 B)False

Question 13

Briefly describe the phenomena of the sunspot cycle.

Accepted Answer

We observe the Sun to exhibit a sunspot

Question 14

How can we best observe the Sun's chromosphere and corona?

Accepted Answer

A) The chromosphere is best observed with infrared telescopes and the corona is best observed with ultraviolet telescopes. 
B) The chromosphere is best observed with ultraviolet telescopes and the corona is best observed with X-ray telescopes. 
C) The chromosphere and corona are both best studied with visible light. 
D) The chromosphere and corona are both best studied with radio telescopes. 
A) The chromosphere is best observed with infrared telescopes and the corona is best observed with ultraviolet telescopes. 
B) The chromosphere is best observed with ultraviolet telescopes and the corona is best observed with X-ray telescopes. 
C) The chromosphere and corona are both best studied with visible light. 
D) The chromosphere and corona are both best studied with radio telescopes.

Question 15

Which of the following is the best answer to the question,"Why does the Sun shine?"

Accepted Answer

A) As the Sun was forming,nuclear fusion reactions in the shrinking clouds of gas slowly became stronger and stronger,until the Sun reached its current luminosity. 
B) As the Sun was forming,gravitational contraction increased the Sun's temperature until the core become hot enough for nuclear fusion,which ever since has generated the heat that makes the Sun shine. 
C) The Sun initially began making energy through chemical reactions.These heated the interior enough to allow gravitational contraction and nuclear fusion to occur. 
D) The Sun initially began generating energy through nuclear fusion as it formed,but today it generates energy primarily through the sunspot cycle. 
A) As the Sun was forming,nuclear fusion reactions in the shrinking clouds of gas slowly became stronger and stronger,until the Sun reached its current luminosity. 
B) As the Sun was forming,gravitational contraction increased the Sun's temperature until the core become hot enough for nuclear fusion,which ever since has generated the heat that makes the Sun shine. 
C) The Sun initially began making energy through chemical reactions.These heated the interior enough to allow gravitational contraction and nuclear fusion to occur. 
D) The Sun initially began generating energy through nuclear fusion as it formed,but today it generates energy primarily through the sunspot cycle.

Question 16

A computer accessory salesman attempts to convince you to purchase a "solar neutrino" shield for your new computer.(It's even "on sale"!)Why do you turn down this excellent offer?

Accepted Answer

A) There's no such thing as a solar neutrino. 
B) Solar neutrinos are generated by solar winds,but we're in a solar minimum now,so the risk of damage is very low. 
C) The Earth's natural magnetic field already offers excellent protection against the onslaught of solar neutrinos. 
D) Neutrinos rarely,if ever,interact with your computer. 
A) There's no such thing as a solar neutrino. 
B) Solar neutrinos are generated by solar winds,but we're in a solar minimum now,so the risk of damage is very low. 
C) The Earth's natural magnetic field already offers excellent protection against the onslaught of solar neutrinos. 
D) Neutrinos rarely,if ever,interact with your computer.

Question 17

Briefly describe why the fact that we detect neutrinos coming from the Sun supports the idea that the Sun generates energy by nuclear fusion.

Accepted Answer

Laboratory experiments and theory show t

Question 18

Which of the following correctly describes how the process of gravitational contraction can make a star hot?

Accepted Answer

A) Gravitational contraction involves nuclear fusion,which generates a lot of heat. 
B) When a star contracts in size,gravitational potential energy is converted to thermal energy. 
C) Heat is generated when gravity contracts,because gravity is an inverse square law force. 
D) Gravitational contraction involves the generation of heat by chemical reactions,much like the burning of coal. 
A) Gravitational contraction involves nuclear fusion,which generates a lot of heat. 
B) When a star contracts in size,gravitational potential energy is converted to thermal energy. 
C) Heat is generated when gravity contracts,because gravity is an inverse square law force. 
D) Gravitational contraction involves the generation of heat by chemical reactions,much like the burning of coal.

Question 19

Sunspots are cooler than the surrounding region of the Sun's surface.

Accepted Answer

A) True 
 B)False

Question 20

Which of the following is not a characteristic of the 11-year sunspot cycle?

Accepted Answer

A) The sunspot cycle is very steady,so that each 11-year cycle is nearly identical to every other 11-year cycle. 
B) The likelihood of seeing solar prominences or solar flares is higher when sunspots are more common and lower when they are less common. 
C) The Sun's entire magnetic field flip-flops at the end of each cycle (at solar minimum). 
D) The number of sunspots on the Sun at any one time gradually rises and falls,with an average of 11 years between the times when sunspots are most numerous. 
A) The sunspot cycle is very steady,so that each 11-year cycle is nearly identical to every other 11-year cycle. 
B) The likelihood of seeing solar prominences or solar flares is higher when sunspots are more common and lower when they are less common. 
C) The Sun's entire magnetic field flip-flops at the end of each cycle (at solar minimum). 
D) The number of sunspots on the Sun at any one time gradually rises and falls,with an average of 11 years between the times when sunspots are most numerous.

Exam 14: Our Star

When is/was gravitational contraction an important energy generation mechanism for the Sun?

Why are neutrinos so difficult to detect?

Which of the following best describes the current status of our understanding of the solar neutrino problem?

In the late 1800s,Kelvin and Helmholtz suggested that the Sun stayed hot thanks to gravitational contraction.What was the major drawback of this idea?

From center outward,which of the following lists the "layers" of the Sun in the correct order?

How much mass does the Sun lose through nuclear fusion per second?

The Sun's surface,as we see it with our eyes,is called the

Every second,the Sun converts about 600 million tons of hydrogen into 596 million tons of helium.The remaining 4 million tons of mass is

The Sun's surface seethes and churns with a bubbling pattern.Why?

Briefly explain how the Sun became hot enough for nuclear fusion.

Process of Science: Why is it important to understand the Sun in order to understand the Earth's radiation belts and space weather?

The proton-proton chain converts four hydrogen nuclei into one helium nucleus.

Briefly describe the phenomena of the sunspot cycle.

How can we best observe the Sun's chromosphere and corona?

Which of the following is the best answer to the question,"Why does the Sun shine?"

A computer accessory salesman attempts to convince you to purchase a "solar neutrino" shield for your new computer.(It's even "on sale"!)Why do you turn down this excellent offer?

Briefly describe why the fact that we detect neutrinos coming from the Sun supports the idea that the Sun generates energy by nuclear fusion.

Which of the following correctly describes how the process of gravitational contraction can make a star hot?

Sunspots are cooler than the surrounding region of the Sun's surface.

Which of the following is not a characteristic of the 11-year sunspot cycle?

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

Surveying the Stars

Star Birth

Star Stuff

The Bizarre Stellar Graveyard

Our Galaxy

Galaxies and the Foundations of Modern Cosmology

Galaxy Evolution

The Birth of the Universe

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

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