Chpt 15 Quiz

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 gases from underneath

Which statement about the Sun's rotation is TRUE?

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

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

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. The Sun's activity cycle shows absolutely no connection to its magnetic field. b. When sunspots are at a minimum we get the largest number of flares and prominences. c. The number of sunspots gets larger and smaller over the course of 11 years. d. Every 11 years sunspots completely cover the Sun making its surface much darker.

c. 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 has the lowest density of atoms?

corona

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

coronal holes

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

d. all of the above

Coronal Mass Ejections from the Sun have many serious effects on or near the Earth. Which of the following is NOT one of these effects? a. disrupting the electronics of satellites b. heating the ionosphere and thus expanding the extent of our planet's atmosphere c. causing power surges and power outages in parts of the Earth near the poles d. causing huge cyclones around the equator of the Earth

d. causing huge cyclones around the equator of the Earth

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

dramatic and sudden changes in the spectrum of the corona

The Sun's chromosphere and corona were discovered

during total eclipses of the Sun

The most common element in the Sun is

hydrogen

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

If you were to glance up at the Sun (which you should not do) the part of the Sun that you can see directly is called its

photosphere

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

spicules

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

the Sun's magnetic field (interacting with the charged particles) heat up the atmosphere

As you go upwards from the Sun's photosphere

the density (number of atoms in a unit volume) 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 material around them (although still very hot compared to Earth temperatures)

How do 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