Download PTYS/ASTR 206 – Section 2 – Fall 2004 Activity #1: 8/25/04

PTYS/ASTR 206 – Section 2 – Spring 2007
Activity #10: 2/27/07
NAME:______KEY_______________________________________________________
The purpose of this activity is to go over material covered both in class and in the textbook. This is an
ACTIVITY, so feel free to discuss these with one or two of your neighbors. You must turn in your
own work.
You decide how much the question is worth! You can choose each number (4, 3, 2, 1) only once.
The total must equal 10 pts. Circle the value you wish for each question. If you do not wish to use this
system of scoring, the values underlined will be used (don’t circle anything in this case).
#1. 4 pts 3 pts 2 pts 1 pt Explain the difference between Earth’s emitted radiation, and
reflected solar radiation. At what part of the electromagnetic spectrum is the spectrum of each of these a
maximum?
Earth’s emitted radiation results from Earth’s heated surface producing electromagnetic
radiation as does any heated object. Earth’s temperature is about 288K, and so, it emits mostly in
the infrared part of the spectrum. Reflected solar radiation is that part of the incoming solar
energy that directly reflects off of Earth’s surface without being absorbed by it. Because of
Earth’s albedo of 0.39, about 39% of incoming radiation is directly reflected off of Earth
(atmosphere and surface). Solar radiation (reflected and incoming) has a maximum in the visible
part of the spectrum.
#2. 4 pts 3 pts 2 pts 1 pt A common misconception is that the ozone hole has something to do
with the greenhouse effect. Based on what you heard in today’s lecture, explain why the ozone hole has
nothing to do with the greenhouse effect.
First, the ozone hole is very small compared to the entire planet, so the amount of heat that gets
through is very small compared to the total amount of energy received globally. Secondly, the
part of the solar spectrum that ozone absorbs – namely, short-wavelength ultraviolet – has a low
intensity and does not significantly contribute to the heating of the surface. Thus, even if it were
ALL let in, it would not lead to any significant heating of Earth’s surface.
#3. 4 pts 3 pts 2 pts 1 pt Which statement is true about the asthenosphere and lithosphere of
Earth? (circle one and give a very brief answer to the question at the end)
A) The asthenosphere and lithosphere are layers in Earth’s upper atmosphere
B) The asthenosphere is another name for Earth’s outer crust, and the lithosphere is the
upper part of the Earth’s mantle
C) The asthenosphere is the fluid-like upper part of Earth’s mantle, and the
lithosphere is the solid crust that rides on top of it
D) The asthenosphere is the region outside of Earth’s magnetopause where solar wind is
diverted around Earth, and the lithosphere is the region inside the magnetopause
containing the Van-Allen radiation belts.
What is the source of energy that drives the motions in these parts of Earth?
Earth’s internal heat is dissipated partly by convection in the asthenosphere which is partially
“plastic” and allows the rigid plates to move over them.
(over for 1 more question)
#4. 4 pts 3 pts 2 pts 1 pt What is the origin of aurora? Why do they appear primarily at high
northerly and southerly latitudes (as opposed to near the equator)?
Aurorae are produced by charged particles colliding with the upper atmosphere of Earth.
These charged particles primarily come from the solar wind that make their way inside of
Earth’s magnetosphere, follow along magnetic field lines that lead to Earth’s polar regions
– hence, they are mostly seen at high northern and southern latitudes.