The Essential Cosmic Perspective, 8e (Bennett et al.)
Chapter 11 Our Star
11.1 Multiple Choice Questions
1) Which of the following is the phase of matter in the interior of the Sun?
A) gas
B) plasma
C) liquid
D) solid
E) a mixture of all of the above
2) What is the approximate temperature of the Sun’s core?
A) 5,800 K
B) 10,000 K
C) 1 million K
D) 15 million K
E) 150 million K
3) The core of the Sun is
A) at the same temperature and density as its surface.
B) at the same temperature but much denser than its surface.
C) much hotter and much denser than its surface.
D) constantly rising to the surface through convection.
E) composed of iron.
4) Based on its surface temperature of 6,000 K, most photons that leave the Sun’s surface lie in
which region of the electromagnetic spectrum?
A) microwave
B) infrared
C) visible
D) ultraviolet
E) X-ray
5) Sunspots are cooler than the surrounding gas in the photosphere because
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.
6) At the time the hypothesis was suggested, what major problem was identified with the idea
that the Sun was powered by gravitational contraction?
A) Contracting objects cool down rather than heat up.
B) This process would power the Sun for only about 25 million years, but geologists already had
evidence the Earth was much older than that.
C) This process could not possibly lead to the observed power output of the Sun.
D) 19th century astronomers should have been able to measure the required change in the Sun’s
size.
7) What keeps the Sun’s outer layers from continuing to fall inward in a gravitational collapse?
A) outward pressure due to super-heated gas
B) the strong force between protons
C) electromagnetic repulsion between protons
D) neutrinos produced by nuclear fusion drag gas outward
8) By what process does the Sun generate energy?
A) nuclear fission
B) nuclear fusion
C) chemical reactions
D) gravitational contraction
E) gradual expansion
9) By what process do nuclear power plants on the Earth generate energy?
A) nuclear fission
B) nuclear fusion
C) chemical reactions
D) converting kinetic energy into electricity
E) converting gravitational potential energy into electricity
10) Hydrogen fusion in the Sun requires a temperature (in Kelvin) of
A) thousands of degrees.
B) millions of degrees.
C) billions of degrees.
D) trillions of degrees.
E) any temperature, as long as gravity is strong enough.
11) At the center of the Sun, nuclear fusion converts hydrogen into
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.
12) How much mass does the Sun lose through nuclear fusion per second?
A) 4 tons
B) 4 million tons
C) 600 tons
D) 600 million tons
E) None; mass-energy is conserved so the sun cannot be losing mass.
13) Suppose you try to bring two protons close together. Because of the electromagnetic force,
the two protons will
A) collide.
B) remain stationary.
C) attract one another.
D) repel one another.
E) join together to form a deuterium nucleus.
14) What is the only force that can overcome the repulsion between two positively charged
nuclei and bind them together?
A) the strong force
B) the weak force
C) the electromagnetic force
D) the gravitational force
E) the Coriolis force
15) What would happen to the core of the sun if its temperature rose slightly?
A) The rate at which fusion occurs would decrease, leading to a contraction of the core, which
would in turn cause the temperature to rise even further.
B) The rate at which fusion occurs would increase, leading to a contraction of the core, which
would in turn cause the temperature to rise even further.
C) The rate at which fusion occurs would increase, leading to an expansion of the core, which
would in turn cause the temperature to drop back down.
D) The rate at which fusion occurs would decrease, leading to an expansion of the core, which
would in turn cause the temperature to drop back down.
16) According to this Doppler map of the sun’s surface, about how fast is the sun rotating around
at its equator?
A) about 200 m/s
B) about 2,000 m/s
C) about 20,000 m/s
D) It is not rotating.
17) What is shown by the small-scale changes in the shading in the figure above?
A) vibrations seen at the solar surface
B) variations in the height of the solar surface
C) variations in the temperature of the photosphere
D) Nothing; this is an artist’s rendering of the sun.
18) Which of the following is not a method astronomers use to determine the physical conditions
inside the Sun?
A) observing X-ray images of the solar interior using satellites
B) building mathematical models that use the laws of physics
C) detecting solar neutrinos generated in the Sun’s core
D) measuring Doppler shifts to observe solar vibrations
19) Studies of solar vibrations have revealed that
A) the Sun vibrates only on the surface.
B) they are caused by processes similar to those that create earthquakes.
C) the Sun generates energy by nuclear fusion.
D) our mathematical models of the solar interior are fairly accurate.
E) neutrinos from the solar core reach the solar surface easily.
20) Imagine that you are trying to stop neutrinos with a lead shield. How thick would you need
to make this shield to ensure that it can stop an average neutrino?
A) about one meter
B) about 700,000 kilometers (the radius of the Sun)
C) about 150 million kilometers (the size of an astronomical unit)
D) about one light-year
E) about 14 billion light-years (the size of the observable universe)
21) Approximately how many neutrinos pass through your body each second?
A) about a thousand trillion
B) about one thousand
C) about 1023
D) None; they are blocked by the Earth’s atmosphere.
22) What is the solution to the solar neutrino problem?
A) The Sun is generating energy other than by nuclear fusion.
B) The Sun is generating much less energy than we think it is.
C) We did not know how to detect neutrinos.
D) Not all fusion reactions create neutrinos.
E) The electron neutrinos created in the Sun’s core change into another type of neutrino that we
did not originally detect.
23) The light radiated from the Sun’s surface reaches Earth in about 8 minutes. However, the
energy of this light was released by fusion in the Sun’s core about
A) 8 minutes ago.
B) 11 years ago.
C) several hundred years ago.
D) several thousand years ago.
E) several hundred thousand years ago.
24) What are coronal holes?
A) regions in the photosphere where magnetic lines gather, creating cooler areas with much less
plasma
B) areas of the corona where magnetic field lines project out into space, allowing charged
particles to escape and form the solar wind
C) areas in the corona that allow us to see through to the photosphere
D) tunnels in the outer layers of the Sun that allow photons to escape and form the solar wind
E) all of the above
25) Why do sunspots appear dark?
A) They are composed of different elements than the rest of the sun.
B) They are regions that do not emit any radiation.
C) They are regions that are significantly cooler than the rest of the photosphere.
D) They are regions nearly devoid of gas.
26) Which of the following statements about the sunspot cycle is not true?
A) The number of sunspots peaks approximately every 11 years.
B) The magnetic polarity of the Sun reverses approximately every 11 years.
C) The rate of nuclear fusion in the Sun peaks about every 11 years.
D) At solar minimum, the first sunspots usually form at mid-latitudes on the Sun.
E) The number of solar flares peaks about every 11 years.
27) Which of the following processes is involved in the sunspot cycle?
A) a slight gravitational contraction of the Sun
B) small variations in the rate of nuclear energy generation in the solar interior
C) an imbalance in the operation of the solar thermostat
D) the winding up of magnetic field lines inside the Sun due to its differential rotation
E) a large change in the amount of visible light emitted by the Sun
28) What observations characterize solar maximum?
A) The Sun becomes much brighter.
B) The Sun emits light of longer average wavelength.
C) The Sun rotates faster at its poles.
D) There are many sunspots visible on the surface of the Sun.
E) all of the above
29) It takes ________ for the sun to progress through one sunspot cycle from a maximum area
covered with sunspots, to a minimum, and back to a maximum. Refer to the graph above.
A) about 110 years
B) about 11 years
C) about 1 year
D) This figure cannot be used to answer this question.
30) Why does the Sun emit neutrinos?
A) Convection releases neutrinos, which random walk through the radiation zone.
B) The Sun does not emit neutrinos.
C) Fusion in the Sun’s core creates neutrinos as a byproduct.
D) Solar flares create neutrinos with magnetic fields.
31) If the sun’s surface cooled, how would its appearance change?
A) It would appear more red.
B) It would appear more blue.
C) It would become bright white.
D) It would stay the same.
11.2 True/False Questions
1) Gravitational equilibrium means that the surface and the core of the Sun are at the same
pressure.
2) Although the Sun does not generate energy by gravitational contraction today, this energy-
generation mechanism was important when the Sun was forming.
3) The Sun generates energy primarily by nuclear fission.
4) Nuclear power plants on Earth create energy in the same way as the Sun.
5) The corona and chromosphere are hotter than the photosphere.
6) The chromosphere is the layer of the Sun that we see as its visible surface.
7) Energy from the core of the Sun first travels slowly through the convection zone and then
much faster through the outer radiation zone.
8) Sunspots are dark because they are cooler than the surrounding region of the Sun’s surface.
9) The temperature of the Sun’s core is about 20,000 K.
10) The proton-proton chain converts four hydrogen nuclei into one helium nucleus plus energy.
11) The Sun’s X-ray and ultraviolet light output is greater than what we would expect based
strictly on its surface temperature.
12) The sun rotates more quickly at the equator than at the poles.
11.3 Process of Science Questions
1) Interdisciplinary Science: Significant advancements in science often occur when several
separate and distinct scientific disciplines come together to address a single question. Use the
search for the Sun’s energy source as a case study. Outline how astronomy and physics were
driven to consider new possibilities for the Sun’s energy by the fields of geology and biology.
2) Nuclear Fusion Power Plants: The public often reacts with fear to any energy source
involving the word “nuclear.” Imagine that you are discussing the problem of energy generation
with a friend, and you mention that nuclear fusion power plants should be investigated. Your
friend expresses worry about all of the nuclear waste that would be produced. How would you
explain to your friend that this fear is misplaced?
3) Basis for Fundamental Solar Data: Table 11.1 in your text lists all of the basic fundamental
data for the Sun: its mass, radius, luminosity, rotation rate, surface temperature, and composition.
Taking each of the quantities in turn, outline the basic observations and physical principles used
to infer the values. When done, consider one final fact about the Sun: its core temperature is
about 15 million degrees (Kelvin). What observations support this value? Do you consider the
Sun’s core temperature to be more or less well established than the basic data of Table 11.1?
Explain.
4) Studying the chromosphere and corona: Consider observations of the solar chromosphere and
corona. What are the principle difficulties in observing them in X-ray, ultraviolet, and in visible
light? What could be done to circumvent those difficulties?
11.4 Short Answer Questions
1) Briefly explain how the Sun became hot enough for nuclear fusion.
2) Describe some of the early theories for the Sun’s energy source and why they are no longer
accepted as viable.
3) What is the solar thermostat?
4) Briefly describe why the detection of neutrinos coming from the Sun supports the theory that
the Sun generates energy by nuclear fusion.
5) What was the solar neutrino problem and how was it solved?
6) Describe two general ways we learn about the Sun’s interior.
7) Imagine you are plunging into the Sun, starting from Earth. Briefly describe what you will
experience on your journey.
8) List at least two ways the sunspot cycle affects us on the Earth.
9) Briefly describe the Sun’s 22 year activity cycle.
10) Briefly explain why sunspots are cooler than surrounding regions of the Sun, and why they
look dark in photos.
11) Imagine nuclear fusion suddenly ceases in the Sun’s core. How long would it take for us to
discover the problem, and how could we discover it? How long would it take for us to experience
the negative consequences of this change, and why?
11.5 Mastering Astronomy Reading Quiz
1) According to modern science, approximately how old is the Sun?
A) 4.5 billion years
B) 25 million years
C) 10,000 years
D) 400 million years
2) The Sun will exhaust its nuclear fuel in about ________.
A) 5000 AD
B) 5 million years
C) 5 billion years
D) 50 billion years
3) Which of the following correctly describes how the process of gravitational contraction can
make a star hot?
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.
4) What two physical processes balance each other to create the condition known as
gravitational equilibrium in stars?
A) the strong force and the weak force
B) gravitational force and outward gas pressure
C) gravitational force and surface tension
D) the strong force and the electromagnetic force
5) The source of energy that keeps the Sun shining today is ________.
A) nuclear fission
B) nuclear fusion
C) gravitational contraction
D) chemical reactions
6) Energy balance in the Sun refers to a balance between ________.
A) the rate at which fusion generates energy in the Sun’s core and the rate at which the Sun’s
surface radiates energy into space
B) the mass that the Sun loses each second and the amount of mass converted into energy each
second
C) the force of gravity pulling inward and the force due to pressure pushing outward
D) the amount of energy the Sun radiates into space and the amount of energy that reaches Earth
7) When we say that the Sun is a ball of plasma, we mean that ________.
A) the Sun is made of material that acts like a liquid acts on Earth
B) the Sun is made of atoms and molecules
C) the Sun consists of gas in which many or most of the atoms are ionized (missing electrons)
D) the Sun has roughly the same composition as blood
8) Approximately, what is the Sun made of (by mass)?
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
9) From center outward, which of the following lists the “layers” of the Sun in the correct order?
A) core, radiation zone, convection zone, photosphere, chromosphere, corona
B) core, radiation zone, convection zone, corona, chromosphere, photosphere
C) core, convection zone, radiation zone, corona, chromosphere, photosphere
D) core, corona, radiation zone, convection zone, photosphere, chromosphere
10) What gives the Sun its slightly mottled appearance when viewed in visible light under high
magnification?
A) We are seeing the tops of convection cells in the photosphere.
B) We are seeing the tops of convection cells in the chromosphere.
C) We are seeing tiny sunspots spread evenly throughout the photosphere.
D) We are seeing through the photosphere to brighter regions that lie deeper down in the Sun.
11) The Sun’s surface is called the ________.
A) photosphere
B) chromosphere
C) corona
D) convection zone
12) The Sun’s average surface (photosphere) temperature is about ________.
A) 5,800 K
B) 1,000,000 K
C) 1,000 K
D) 37,000 K
13) What is the solar wind?
A) a stream of charged particles flowing outward from the surface of the Sun
B) the uppermost layer of the Sun, lying just above the corona
C) the strong wind that blows sunspots around on the surface of the Sun
D) the wind that causes huge arcs of gas to rise above the Sun’s surface
14) The fundamental nuclear reaction occurring in the core of the Sun is ________.
A) nuclear fission
B) radioactive decay
C) nuclear fusion of hydrogen into helium
D) nuclear fusion of helium into carbon
15) The proton-proton chain is ________.
A) the specific set of nuclear reactions through which the Sun fuses hydrogen into helium
B) the linkage of numerous protons into long chains
C) another name for the force that holds protons together in atomic nuclei
D) an alternative way of generating energy that is different from the fusion of hydrogen into
helium
16) The overall result of the proton-proton chain is ________.
A) 4 H becomes 1 He + energy
B) 6 H becomes 1 He + energy
C) p + p becomes 2H + energy
D) individual protons are joined into long chains of protons
17) To estimate the central temperature of the Sun, scientists ________.
A) send probes to measure the temperature
B) use hot gas to create a small Sun in a laboratory
C) monitor changes in Earth’s atmosphere
D) use computer models to predict interior conditions
18) Why are neutrinos so difficult to detect?
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) They are negatively charged, which allows them to pass through most material.
19) The particles ejected from the Sun during a coronal mass ejection, if directed at Earth, will
reach us
A) in about 8 minutes.
B) in about 8 hours.
C) in several days.
D) in about a year.
20) What happens to energy in the Sun’s convection zone?
A) Energy is transported outward by the rising of hot 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.
21) What do sunspots, solar prominences, and solar flares all have in common?
A) They are all strongly influenced by magnetic fields on the Sun.
B) They all have about the same temperature.
C) They are all shaped by the solar wind.
D) They all occur only in the Sun’s photosphere.
22) Which of the following is not a characteristic of the 11-year sunspot cycle?
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 with each sunspot cycle, so that the overall
magnetic cycle averages 22 years.
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.
23) How is the sunspot cycle directly relevant to us here on Earth?
A) Coronal mass ejections and other activity associated with the sunspot cycle can disrupt radio
communications and knock out sensitive electronic equipment.
B) The sunspot cycle strongly influences Earth’s weather.
C) The Sun’s magnetic field, which plays a major role in the sunspot cycle, affects compass
needles that we use on Earth.
D) The brightening and darkening of the Sun that occurs during the sunspot cycle affects plant
photosynthesis here on Earth.
E) The sunspot cycle is the cause of global warming.
11.6 Mastering Astronomy Concept Quiz
1) 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?
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.
2) When is/was gravitational contraction an important energy generation mechanism for the Sun?
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.
3) What do we mean when we say that the Sun is in gravitational equilibrium?
A) There is a balance within the Sun between the outward force of gas pressure and the inward
force of gravity.
B) The Sun maintains a steady temperature.
C) The hydrogen gas in the Sun is balanced so that it never rises upward or falls downward.
D) The Sun always has the same amount of mass, creating the same gravitational force.
4) Which of the following is the best answer to the question, “Why does the Sun shine?”
A) As the Sun was forming, gravitational contraction increased the Sun’s temperature until the
core became hot enough for nuclear fusion, which ever since has generated the energy that
makes the Sun shine.
B) 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.
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.
5) How does the Sun’s mass compare to Earth’s mass?
A) The Sun’s mass is about 300,000 times the mass of the Earth.
B) The Sun’s mass is about 300 times the mass of the Earth.
C) The Sun’s mass is about 30 times the mass of the Earth.
D) Both have approximately the same mass.
6) Which of the following best describes why the Sun emits most of its energy in the form of
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.
7) The Sun’s surface seethes and churns with a bubbling pattern. Why?
A) We are seeing hot gas rising and cool gas falling due to the convection that occurs beneath the
surface.
B) The Sun’s surface is boiling.
C) The churning gas is being stirred up by the strong solar wind.
D) The churning is an illusion created by varying radiation, as the gas on the Sun’s surface is
actually quite still.
8) Which of the following correctly compares the Sun’s energy generation process to the energy
generation process in human-built nuclear power plants?
A) The Sun generates energy by fusing small nuclei into larger ones, while our power plants
generate energy by the fission (splitting) of large nuclei.
B) Both processes involve nuclear fusion, but the Sun fuses hydrogen while nuclear power plants
fuse uranium.
C) The Sun generates energy through nuclear reactions while nuclear power plants generate
energy through chemical reactions.
D) The Sun generates energy through fission while nuclear power plants generate energy through
fusion.
9) 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 ________.
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) ejected mostly as solar neutrinos
10) Which of the following best explains why nuclear fusion requires bringing nuclei extremely
close together?
A) Nuclei normally repel because they are all positively charged and can be made to stick only
when brought close enough for the strong force to take hold.
B) Nuclei are attracted to each other by the electromagnetic force, but this force is only strong
enough to make nuclei stick when they are very close together.
C) Nuclei have to be very hot in order to fuse, and the only way to get them hot is to bring them
close together.
D) Fusion can proceed only by the proton-proton chain, and therefore requires that protons come
close enough together to be linked up into a chain.
11) If the Sun’s core suddenly shrank a little bit, what would happen in the Sun?
A) The core would heat up, fusion rates would increase, the core would re-expand.
B) The core would cool off and continue to shrink as its density increased.
C) The density of the core would decrease, causing the core to cool off and expand.
D) The core would heat up, causing it to radiate so much energy that it would shrink even more.
12) Why does the Sun emit neutrinos?
A) Solar flares create neutrinos with very energetic magnetic fields.
B) Fusion in the Sun’s core creates neutrinos when protons turn into neutrons.
C) Convection releases neutrinos, which random walk through the radiation zone.
D) Fission in the Sun’s core creates neutrinos when protons turn into neutrons.
E) The annihilation of positrons and electrons in the core produces neutrinos.
13) If the Sun suddenly stopped emitting neutrinos, what might we infer (after checking that our
neutrino detectors were still operational)?
A) Fusion reactions in the Sun have ceased.
B) Fusion reactions in the Sun ceased a few hundred thousand years ago.
C) Fission reactions in the Sun have ceased.
D) The Sun has exhausted its supply of neutrinos.
14) Why do sunspots appear dark in pictures of the Sun?
A) They actually are fairly bright, but appear dark against the even brighter background of the
surrounding photosphere.
B) They are too cold to emit any visible light.
C) They are holes in the solar surface through which we can see through to deeper, darker layers
of the Sun.
D) They are extremely hot and emit all their radiation as X-rays rather than visible light.
15) The star Alpha Centauri A is the same type of star as the Sun, but its luminosity is about 1.6
times that of the Sun. What can we conclude?
A) Alpha Centauri A fuses hydrogen into helium in its core at a higher rate than our Sun.
B) Alpha Centauri A has a surface temperature about 1.6 times hotter than the Sun.
C) Alpha Centauri A is much farther from Earth than the Sun.
D) Alpha Centauri A must have a vastly different interior structure than the Sun.
16) How can we best observe the Sun’s chromosphere and corona?
A) The chromosphere is best observed with ultraviolet telescopes and the corona is best observed
with X-ray telescopes.
B) The chromosphere is best observed with infrared telescopes and the corona is best observed
with ultraviolet 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.
17) The intricate patterns visible in an X-ray image of the Sun generally show ________.
A) helioseismological fluctuations
B) a bubbling pattern on the photosphere
C) extremely hot plasma flowing along magnetic field lines
D) structure within sunspots
18) How can we measure the strength of magnetic fields in sunspots?
A) by measuring the splitting of spectral lines in the spectrum of the sunspot
B) by observing the sizes of sunspots
C) by noticing the effect they have on orbiting spacecraft
D) only by using sophisticated computer models because there are no observational ways of
measuring magnetic field strength
19) Satellites in low-Earth orbits are more likely to crash to Earth when the sunspot cycle is near
solar maximum because ________.
A) it is too dangerous to send the Space Shuttle to service satellites during solar maximum
B) Earth’s upper atmosphere tends to expand during solar maximum, exerting more drag on
satellites in low orbits
C) the engines on the satellites can be destroyed by the intense radiation from large solar flares
D) they are more likely to have their electronics “fried” by a solar flare during solar maximum
20) Recent claims that global warming is due to changes in solar irradiance related to sunspot
activity are
A) unlikely since global temperatures have continued to rise even though solar irradiance has
not.
B) unlikely since the sun actually produces less energy during sunspot maximum.
C) likely because there is a correlation between recent global temperatures and solar irradiance.
D) likely because global warming is not being caused by human activity.
21) 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?
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.