Astronomy Test 1

Which statement about the Sun's rotation is TRUE?

The Sun rotates at different rates at different latitudes on the Sun

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

The number of sunspots gets larger and smaller over the course of 11 years

The hottest zone in the sun is the...

core

Which part of the Sun's atmosphere is the hottest

corona

The most common element in the Sun is...

Hydrogen

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

Sunspots are places where the strong magnetic fields in the Sun resist the upward motion of bubbling hot gasses from underneath

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

They measure the Zeeman effect (the splitting of spectral lines)

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

We take an absorption line spectrum of the Sun, and the absorption lines tell us what elements are present in the outer layers

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:

aurorae (northern and southern lights)

Coronal Mass Ejections from the Sun have serious effects on or near the Earth. Which of the following is NOT one of these effects?

causing huge cyclones around the equator of the Earth

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

chromosphere

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

corona

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

coronal holes

Recently, some engineers and scientists have proposed building spaceships with enormous "sails" that catch the solar winf 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?)?

electrons and protons

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

granulation

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?

historical records of the number of sunspots seen on the Sun, measuring the amount of radioactive carbon in tree rings, historical records of auroral activity

The granulation pattern that astronomers have observed on the surface of the sun tells us that...

hot material must be rising from the Sun's hotter interior

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

is made entirely of hot gas

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

loops of magnetic field emerging from the surface of the Sun

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

plagues

as you go upwards from the Sun's photosphere...

the density (the number of atoms) decreases

The Sun's photosphere is...

the part of the Sun from which the light comes that we see when we look at the Sun with our eyes

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

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