Question 1

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

Accepted Answer

A) True 
 B)False  True

Question 2

The source of energy that keeps the Sun shining today is ________.

Accepted Answer

A)  nuclear fission 
B)  nuclear fusion 
C)  gravitational contraction 
D)  chemical reactions 
A)  nuclear fission 
B)  nuclear fusion 
C)  gravitational contraction 
D)  chemical reactions B

Question 3

Imagine you are plunging into the Sun, starting from Earth. Briefly describe what you will experience on your journey.

Accepted Answer

First you will experience the light of the Sun and the pressure of particles from the solar wind. As you approach within a few radii of the Sun, you will enter the corona, an extremely hot, but tenuous layer of gas. The next layer you encounter will be the chromosphere, a hot layer of gas just above the visible surface of the Sun. As you plunge through the Sun's "surface", the photosphere, the temperature if the gas will be about 5,800 K, which is cooler than the outer layers. You will also see the slightly cooler regions of sunspots and the granulation on the surface caused by the convection underneath. You will then enter this convective layer, feeling regions of hot plasma rising upward to meet you and seeing cooler gas descending from the surface. After passing through this layer, you will reach the radiation zone, where photons are engaged in a random dance as they are continuously absorbed and reemitted by the hot gas there. You will then reach the source of these photons, the core of the Sun, which is actively involved in nuclear fusion, converting hydrogen into helium and releasing multitudes of photons and neutrinos.

Question 4

What happens to energy in the Sun's convection zone?

Accepted Answer

A)  Energy is transported outward by the rising of hot plasma and sinking of cooler plasma. 
B)  Energy is produced in the convection zone by thermal radiation. 
C)  Energy slowly leaks outward through the radiative diffusion of photons that repeatedly bounce off ions and electrons. 
D)  Energy is produced in the convection zone by nuclear fusion. 
A)  Energy is transported outward by the rising of hot plasma and sinking of cooler plasma. 
B)  Energy is produced in the convection zone by thermal radiation. 
C)  Energy slowly leaks outward through the radiative diffusion of photons that repeatedly bounce off ions and electrons. 
D)  Energy is produced in the convection zone by nuclear fusion.

Question 5

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

Accepted Answer

The Sun formed from a cloud of gas. As i

Question 6

The intricate patterns visible in an X-ray image of the Sun generally show ________.

Accepted Answer

A)  helioseismological fluctuations 
B)  a bubbling pattern on the photosphere 
C)  extremely hot plasma flowing along magnetic field lines 
D)  structure within sunspots 
A)  helioseismological fluctuations 
B)  a bubbling pattern on the photosphere 
C)  extremely hot plasma flowing along magnetic field lines 
D)  structure within sunspots

Question 7

The temperature of the Sun's core is about 20,000 K.

Accepted Answer

A) True 
 B)False

Question 8

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

Question 9

The light radiated from the Sun's surface reaches Earth in about 8 minutes, but the energy of that light was released by fusion in the solar core about ________.

Accepted Answer

A)  few hundred thousand years ago 
B)  three days ago 
C)  one hundred years ago 
D)  one thousand years ago 
A)  few hundred thousand years ago 
B)  three days ago 
C)  one hundred years ago 
D)  one thousand years ago

Question 10

Sunspots are cooler than the surrounding gas in the photosphere because

Accepted Answer

A)  they are regions where convection carries cooler material downward. 
B)  strong magnetic fields slow convection and prevent hot plasma from entering the region. 
C)  magnetic fields trap ionized gases that absorb light. 
D)  there is less fusion occurring there. 
E)  magnetic fields lift material from the sunspot and quickly cool the material. 
A)  they are regions where convection carries cooler material downward. 
B)  strong magnetic fields slow convection and prevent hot plasma from entering the region. 
C)  magnetic fields trap ionized gases that absorb light. 
D)  there is less fusion occurring there. 
E)  magnetic fields lift material from the sunspot and quickly cool the material.

Question 11

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 12

Which of the following statements is an inference from a model (rather than an observation)?

Accepted Answer

A)  The photosphere is made out of mainly hydrogen and helium. 
B)  The corona is hotter than the photosphere. 
C)  The photosphere emits visible light. 
D)  The Sun emits neutrinos. 
E)  The Sun's core is gradually turning hydrogen into helium. 
A)  The photosphere is made out of mainly hydrogen and helium. 
B)  The corona is hotter than the photosphere. 
C)  The photosphere emits visible light. 
D)  The Sun emits neutrinos. 
E)  The Sun's core is gradually turning hydrogen into helium.

Question 13

What is the Sun made of (by mass)?

Accepted Answer

A)  70% hydrogen, 28% helium, 2% other elements 
B)  100% hydrogen and helium 
C)  50% hydrogen, 25% helium, 25% other elements 
D)  90% dark matter, 10% ordinary matter 
A)  70% hydrogen, 28% helium, 2% other elements 
B)  100% hydrogen and helium 
C)  50% hydrogen, 25% helium, 25% other elements 
D)  90% dark matter, 10% ordinary matter

Question 14

Which of the following best describes why the Sun emits most of its energy in the form of visible light?

Accepted Answer

A)  Like all objects, the Sun emits thermal radiation with a spectrum that depends on its temperature, and the Sun's surface temperature is just right for emitting mostly visible light. 
B)  Nuclear fusion in the Sun's core produces visible light photons. 
C)  The visible light comes from energy level transitions as electrons in the Sun's hydrogen atoms jump between level 1 and level 2. 
D)  The Sun's gas is on fire like flames from wood or coal, and these flames emit visible light. 
A)  Like all objects, the Sun emits thermal radiation with a spectrum that depends on its temperature, and the Sun's surface temperature is just right for emitting mostly visible light. 
B)  Nuclear fusion in the Sun's core produces visible light photons. 
C)  The visible light comes from energy level transitions as electrons in the Sun's hydrogen atoms jump between level 1 and level 2. 
D)  The Sun's gas is on fire like flames from wood or coal, and these flames emit visible light.

Question 15

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

Accepted Answer

A)  It predicted that the Sun could shine for about 25 million years, but geologists had already found that Earth is much older than this. 
B)  It predicted that the Sun would shrink noticeably as we watched it, but 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 in size with time, which would make it impossible to have stable geology on our planet. 
A)  It predicted that the Sun could shine for about 25 million years, but geologists had already found that Earth is much older than this. 
B)  It predicted that the Sun would shrink noticeably as we watched it, but 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 in size with time, which would make it impossible to have stable geology on our planet.

Question 16

All but one of the following statements describe why scientists doubt the solar sunspot cycle affects global climate. Identify which statement is irrelevant to the explanation.

Accepted Answer

A)  Solar winds can affect satellite communications. 
B)  The solar cycle varies every 11 years; average Earth temperatures do not show an 11 year variation. 
C)  The variations in solar particle winds do not change the temperature of the Earth's ocean or ground. 
D)  Variations in solar activity affect the Sun's luminosity by a very tiny amount. 
A)  Solar winds can affect satellite communications. 
B)  The solar cycle varies every 11 years; average Earth temperatures do not show an 11 year variation. 
C)  The variations in solar particle winds do not change the temperature of the Earth's ocean or ground. 
D)  Variations in solar activity affect the Sun's luminosity by a very tiny amount.

Question 17

Nuclear power plants on Earth create energy in the same way as the Sun.

Accepted Answer

A) True 
 B)False

Question 18

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

Accepted Answer

A)  When a star contracts in size, gravitational potential energy is converted to thermal energy. 
B)  Gravitational contraction involves nuclear fusion, which generates a lot of heat. 
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)  When a star contracts in size, gravitational potential energy is converted to thermal energy. 
B)  Gravitational contraction involves nuclear fusion, which generates a lot of heat. 
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

At the center of the Sun, nuclear fusion converts hydrogen into

Accepted Answer

A)  hydrogen compounds such as methane. 
B)  molecular hydrogen. 
C)  radiation and elements such as carbon and nitrogen. 
D)  radioactive elements such as uranium and plutonium. 
E)  helium, gamma rays, and neutrinos. 
A)  hydrogen compounds such as methane. 
B)  molecular hydrogen. 
C)  radiation and elements such as carbon and nitrogen. 
D)  radioactive elements such as uranium and plutonium. 
E)  helium, gamma rays, and neutrinos.

Question 20

What would happen if the fusion rate in the core increased but the core could not expand?

Accepted Answer

A)  The Sun's core would heat and the rate of fusion would increase further. 
B)  The Sun's core would reach a new equilibrium, but at a cooler temperature. 
C)  The Sun's core would cool and the rate of fusion would decrease. 
D)  The Sun's core would reach a new equilibrium, but at a higher temperature. 
A)  The Sun's core would heat and the rate of fusion would increase further. 
B)  The Sun's core would reach a new equilibrium, but at a cooler temperature. 
C)  The Sun's core would cool and the rate of fusion would decrease. 
D)  The Sun's core would reach a new equilibrium, but at a higher temperature.

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

The source of energy that keeps the Sun shining today is ________.

Imagine you are plunging into the Sun, starting from Earth. Briefly describe what you will experience on your journey.

What happens to energy in the Sun's convection zone?

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

The intricate patterns visible in an X-ray image of the Sun generally show ________.

The temperature of the Sun's core is about 20,000 K.

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?

The light radiated from the Sun's surface reaches Earth in about 8 minutes, but the energy of that light was released by fusion in the solar core about ________.

Sunspots are cooler than the surrounding gas in the photosphere because

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 ________.

Which of the following statements is an inference from a model (rather than an observation)?

What is the Sun made of (by mass)?

Which of the following best describes why the Sun emits most of its energy in the form of visible light?

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

All but one of the following statements describe why scientists doubt the solar sunspot cycle affects global climate. Identify which statement is irrelevant to the explanation.

Nuclear power plants on Earth create energy in the same way as the Sun.

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

At the center of the Sun, nuclear fusion converts hydrogen into

What would happen if the fusion rate in the core increased but the core could not expand?

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

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

The Beginning of Time

Life in the Universe

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Exam 10: Our Star

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

The source of energy that keeps the Sun shining today is ________.

Imagine you are plunging into the Sun, starting from Earth. Briefly describe what you will experience on your journey.

What happens to energy in the Sun's convection zone?

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

The intricate patterns visible in an X-ray image of the Sun generally show ________.

The temperature of the Sun's core is about 20,000 K.

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?

The light radiated from the Sun's surface reaches Earth in about 8 minutes, but the energy of that light was released by fusion in the solar core about ________.

Sunspots are cooler than the surrounding gas in the photosphere because

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 ________.

Which of the following statements is an inference from a model (rather than an observation)?

What is the Sun made of (by mass)?

Which of the following best describes why the Sun emits most of its energy in the form of visible light?

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

All but one of the following statements describe why scientists doubt the solar sunspot cycle affects global climate. Identify which statement is irrelevant to the explanation.

Nuclear power plants on Earth create energy in the same way as the Sun.

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

At the center of the Sun, nuclear fusion converts hydrogen into

What would happen if the fusion rate in the core increased but the core could not expand?

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

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

The Beginning of Time

Life in the Universe

Filters