Deck 15: The Sun: a Garden-Variety Star

Question 1

As you go upwards from the Sun's photosphere,

A) the temperature decreases
B) the density (number of atoms in a unit volume) decreases
C) the layers get easier to see with the unaided eye
D) the kinds of atoms present change drastically
E) only red light can emerge

Answer 1

the density (number of atoms in a unit volume) decreases

Question 2

Which part of the Sun's atmosphere is the hottest?

A) chromosphere
B) transition region
C) corona
D) just above the photosphere
E) you can't fool me, all these regions are at roughly the same temperature

Answer 2

corona

Question 3

Sunspots are darker than the regions of the Sun around them because

A) they consist of different elements than the rest of the Sun
B) they are located in the corona and not on the photosphere
C) they move much faster around the Sun than other material and thus heat up
D) they are the shadows of the planets and asteroids seen on the bright surface of the Sun
E) they are cooler than the material around them (although still very hot compared to Earth temperatures)

Answer 3

they are cooler than the material around them (although still very hot compared to Earth temperatures)

Question 4

The Sun's chromosphere contains many jet-like projections that stick up into the transition region. These spikes of gas are called:

A) coronae
B) spicules
C) plages
D) flares
E) prominences

Question 5

What mechanisms do astronomers believe is responsible for making the Sun's outer atmosphere so much hotter than its photosphere?

A) stirring by comets, meteors, and other pieces of solid material being pulled in by the Sun's strong gravity
B) light reflected back from the terrestrial planets
C) the Sun's magnetic field interacting with the charged particles that make up the atmosphere
D) the ionization of a new element called coronium
E) astronomers really don't have even a guess about what heats the Sun's outermost layers

Question 6

The Sun's photosphere is

A) the central region where the energy of the Sun originates
B) the part of the Sun from which the light comes that we see when we look at the Sun with our eyes
C) the hottest region of the Sun
D) the outermost layers of the Sun's atmosphere
E) the first region you would come to when leaving the core

Question 7

Which part of the Sun's atmosphere has the lowest density (number of atoms per unit volume)?

A) corona
B) transition region
C) chromosphere
D) just above the photosphere
E) you can't fool me, all these regions are at roughly the same density

Question 8

The Sun's chromosphere and corona were discovered

A) using the first telescopes Galileo built
B) in the late 19th century through the use of a spectrograph
C) during total eclipses of the Sun
D) using spacecraft that orbited Venus, a planet with a better view of the Sun
E) by ancient shepherds, who saw reflections of the Sun in quiet pools of water

Question 9

The ten million tons of particles that escape the Sun each year in the form of the solar wind get out mainly through regions called

A) sunspots
B) spicules
C) aurorae
D) coronal holes
E) transition regions

Question 10

The hottest zone in the Sun is the

A) photosphere
B) radiative zone
C) core
D) convection zone
E) chromosphere

Question 11

Astronomers first detected the presence of a wind of particles coming from the Sun by

A) sending a spacecraft much closer to the Sun than the planet Mercury
B) by noting its effects on the atmosphere of Venus
C) by dramatic and sudden changes in the spectrum of coronium
D) using the experiments aboard Sputnik 1, the first spacecraft to go above the Earth's atmosphere
E) by noting the wind's effects on the tails of comets

Question 12

The hotter region directly above the Sun's visible surface is called the

A) chromosphere
B) photosphere
C) corona
D) ionization region
E) convection zone

Question 13

The granulation pattern that astronomers have observed on the surface of the Sun tells us that:

A) the Sun is a lot cooler on the inside than on the outside
B) the Sun's surface is made of a thin solid that cracks easily
C) hot material must be rising from the Sun's hotter interior
D) the solar wind must consist of very small (low-mass) particles
E) the Sun accumulates a lot of dirt and dust because of its large gravity
Section 15.2: The Solar Cycle

Question 14

As astronomers have learned more about the structure of the Sun, they have found that it

A) has a small solid core inside
B) is made entirely of liquid, with a tiny bit of hot gas on the outside
C) is solid throughout, but with a large very hot atmosphere
D) is made entirely of hot gas
E) is made of billions of individual pieces of hot rock, all orbiting around each other in a whirling arrangement

Question 15

The most common element in the Sun is

A) helium
B) iron
C) hydrogen
D) water
E) nitrogen

Question 16

Solar wind particles can be captured by the Earth's magnetosphere. When these particles spiral down along the magnetic field into the atmosphere, they are responsible for:

A) aurorae (northern and southern lights)
B) tropical storms (regions of rapidly rotating air)
C) the greenhouse effect
D) the reddish color we see during sunsets
E) the poor quality of television programming in the world's northern hemisphere

Question 17

How do astronomers know what the outer layers of the Sun are made of?

A) we send graduate students there to get samples
B) several spacecraft with good shielding have approached the Sun and obtained samples
C) the surface layers of Mercury have been laid down by the Sun and are thus made of the same material as the Sun
D) the Sun's wind gives us an accurate measure of all the different elements in the Sun
E) we take an absorption line spectrum of the Sun, and the absorption lines tell us what elements are present in the outer layers

Question 18

Which of the following statements about the Sun's photosphere is NOT TRUE?

A) The photosphere is significantly hotter than all the layers of the Sun beneath it (further inward)
B) The photosphere is not a solid layer; if a spaceship (that could withstand the heat) fell through it, it wouldn't feel anything when reaching the photosphere
C) The photosphere is much less dense than our Earth's atmosphere
D) The photosphere is the layer where the Sun becomes opaque (you can't see through it)
E) Through a telescope, the photosphere looks mottled or granulated

Question 19

You are out on the beach, enjoying the warm sunshine with friends. As you glance up at the Sun (only briefly we hope), the part of the Sun that you can see directly is called its:

A) corona
B) photosphere
C) chromosphere
D) core
E) heliopause

Question 20

Which statement about the Sun's rotation is TRUE?

A) The Sun does not rotate; only planets rotate
B) The Sun rotates once a day
C) The Sun rotates at different rates at different latitudes on the Sun
D) The Sun rotates only at the equator, where the sunspots are found; the rest of the Sun does not rotate
E) Only the atmosphere of the Sun rotates, not the main body of the Sun

Question 21

Recently, some engineers and scientists have proposed building spaceships with enormous "sails" that catch the solar wind and use it to move the ship. What kinds of particles would be hitting this sail (i.e., what is the solar wind mostly made of):

A) nuclei of heavier atoms such as iron and nickel
B) calcium atoms
C) electrons and protons
D) gamma-rays
E) scientists do not have any idea of the composition of the solar wind; it is very mysterious

Question 22

Which of the following statements about the violent events on the Sun called flares is FALSE?

A) flares happen more often during solar maximum, and sometimes during those periods, there can be several in one day
B) a flare can release energy equivalent to a million hydrogen bombs
C) flares originate in the upper part of the corona, in the regions called coronal holes
D) astronomers think that flares are connected with sudden changes in the magnetic field of the Sun
E) the visible light we see from a flare is only a tiny fraction of the energy it releases

Question 23

Which of the following is not part of some active regions on the Sun?

A) sunspots
B) flares
C) plages
D) prominences
E) granulation

Question 24

Astronomers have concluded that the Sun's activity varies in an 11-year cycle. Which of the following statements about this cycle is TRUE:

A) Every 11 years sunspots completely cover the Sun, making its surface much darker
B) The number of sunspots gets larger and smaller over the course of 11 years
C) When sunspots are at a minimum, we get the largest number of flares and prominences
D) The Sun's activity cycle shows absolutely no connection to its magnetic field
E) The Sun's activity cycle is directly connected to the number of earthquakes at the continental plate boundaries on Earth

Question 25

Astronomers now realize that active regions on the Sun are connected with

A) the dark regions between the bright granulation cells on the photosphere
B) loops of magnetic field emerging from the surface of the Sun
C) the absence of sunspots during a solar minimum
D) great tropical storm systems in the Earth's atmosphere
E) changes in the gravitational pull of the Sun over different parts of its photosphere
Section 15.4: Space Weather

Question 26

What is the best reason astronomers have come up with to explain why sunspots are cooler and look darker?

A) Sunspots are holes (less dense regions) in the Sun's photosphere, through which we can see the darker regions of the Sun below
B) Sunspots are places where the strong magnetic fields in the Sun resist the upward motion of bubbling hot gases from underneath
C) Sunspots are regions where carbon clouds high above the photosphere gather and these dark clouds block the light from underneath them
D) Sunspots are regions in the upper chromosphere where there is a lot of coronium, which absorbs light
E) Sunspots are so mysterious and difficult to explain, astronomers really don't have idea what causes them
Section 14.3: Solar Activity above the Photosphere

Question 27

Astronomers have found that the level of the Sun's activity varies over the centuries. How did they come to realize that this is so:

A) historical records of the number of sunspots seen on the Sun
B) measuring the amount of radioactive carbon in tree rings
C) historical records of auroral activity
D) all of the above
E) none of the above

Question 28

When we use the light of atoms such as hydrogen and calcium to examine the Sun's outer layers, we can see bright "clouds" in the chromosphere right around the location of sunspots. These bright clouds are given the name:

A) granules
B) spot umbras
C) active regions
D) Zeeman rings
E) plages

Question 29

A Canadian college student who has taken an astronomy class goes home for the holidays and persuades his parents to let him borrow the family car. When he returns, he finds that his parents are very angry with him, claiming he left the garage door open. Yet he remembers that he carefully closed the garage door with the electronic remote control in the car. After consulting with his astronomy instructor, he comes up with an alternative explanation for why the garage door is open. Which of the following is PART of that explanation?

A) The Sun was so bright and high in the sky in December in Canada that it got into his parents' eyes
B) There was an eclipse of the Sun
C) It was a time of solar maximum, and there had been a big flare on the Sun earlier
D) No aurorae had been seen in the sky for many months
E) The number of sunspots had reached an all-time minimum

Question 30

How do astronomers know how strong the magnetic field of the Sun is?

A) they measure the magnetic field of the Earth, which is a direct result of the magnetic field of the Sun
B) they measure the Sun's rotation using the Doppler effect
C) they count the number of days in the year that we get an aurora in the upper atmosphere
D) the measure the Zeeman effect (the splitting of spectral lines)
E) the diameter of a star is directly related to the size of its magnetic field