Question 1

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):

Accepted Answer

The solar wind is mostly made up of charged particles, specifically electrons and protons. While there may be some heavier nuclei and other particles present, they make up a very small fraction of the solar wind.

Question 2

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

Accepted Answer

The answer of Which of the following statements about the...

Question 3

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

Accepted Answer

Granulation is not an active region on the Sun. It refers to the pattern of small bright and dark cells, caused by convection, that covers the surface of the Sun. It is not associated with any particular activity or phenomena.

Question 4

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

Accepted Answer

The activity cycle is characterized by the number of sunspots on the Sun's surface, which varies from a minimum to a maximum over an 11-year period. This cycle is also associated with variations in other solar activity, such as flares, coronal mass ejections, and the solar wind.

Question 5

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

Accepted Answer

Active regions on the Sun are caused by loops of magnetic field emerging from the surface of the Sun, which are often associated with sunspots and other solar activity.

Question 6

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

Accepted Answer

Sunspots are cooler and look darker because they are places where the strong magnetic fields in the Sun resist the upward motion of bubbling hot gases from underneath, blocking the light and making them look darker.

Question 7

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:

Accepted Answer

Astronomers have used all of these methods to determine the variability of the Sun's activity. Historical records of sunspots have been kept since the early 17th century, and these records show a cyclic pattern of activity. Measuring the amount of radioactive carbon in tree rings allows scientists to determine how much cosmic radiation is reaching the Earth, which in turn can be used to indirectly measure solar activity. Historical records of auroral activity also provide evidence of solar activity variations.

Question 8

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:

Accepted Answer

The bright "clouds" in the chromosphere around sunspots are called plages.

Question 9

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?

Accepted Answer

The explanation given by the astronomy instructor is likely related to the solar maximum and the occurrence of a big flare on the Sun, which could have interfered with the electronic signal from the remote control to the garage door.

Question 10

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

Accepted Answer

Astronomers measure the magnetic field of the Sun by observing the Zeeman effect, which is the splitting of spectral lines in the Sun's spectrum caused by its magnetic field. This allows them to determine the strength and orientation of the magnetic field in different regions of the Sun.

Quiz 15: The Sun: a Garden-Variety Star

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) :