Transcript Today`s Powerpoint - Physics and Astronomy

Clicker Question:
The surface gravity of the moon is 1/6 that
of Earth. If Matt weighs 120 lbs on Earth,
how much does he weigh standing on the
moon?
A: 120 lbs
B: 60 lbs
C: 30 lbs
D: 20 lbs
E: 10 lbs
Clicker Question:
Suppose the Moon was half as dense, but the
same size. How much would Matt (120 lbs
on Earth) weigh?
A: 120 lbs
B: 60 lbs
C: 30 lbs
D: 20 lbs
E: 10 lbs
Earth and the Moon in Bulk
Density of surface rocks on moon similar to overall density of 3.3 g/cm3
This + magnetometer data suggests Moon’s iron core is small – 300 km
Earth and the Moon
• Moon stabilizes Earth’s rotational axis, maintains 23.5 degree tilt
=> gives us stable climate, seasons, etc.
• Earth’s rotational period is slowing down – day is getting longer
Moon is moving away from earth => 3.8 cm or 1.5 inches per year
Magnetospheres
The magnetosphere is the region around Earth where
charged particles from the solar wind are trapped.
Magnetospheres
These charged
particles are trapped
in areas called the
Van Allen belts,
where they spiral
around the magnetic
field lines.
Magnetospheres
Near the poles, the
Van Allen belts
intersect the
atmosphere. The
charged particles
can escape; when
they do, they create
glowing light called
an aurora.
Aurora over Iceland – March 18, 2012
NASA: Astronomy Picture of the Day (http://apod.nasa.gov/apod/)
The Greenhouse Effect
Main greenhouse
gases are H2O and
CO2 .
O2
– 21%
H2O – 0-4%
CO2 – 0.039%
If no greenhouse
effect, surface
would be 26o F
Intergovernmental Panel on Climate
Change (IPCC – UN Agency) says
Translating terminology into probabilities
Intergovernmental Panel on Climate
Change (IPCC – UN Agency) says
What does this mean?
The consensus of the IPCC is that there is a 90% probability that
human activity contributed signifcantly to the 1 degree F increase in
global temperature over the past 50 years.
About 2 degrees F since 1850
Temperature for last 14,000 years
Global Warming Basics
Burning Fossil Fuels is the Primary Cause
C + O2
CO2
Global Warming: The Greatest Threat © 2006 Deborah L. Williams
(Combustion)
Burning carbon-containing fossil fuels
produces carbon dioxide.
Global Warming Basics
391ppm
 Humans have increased
carbon dioxide (CO2) in the
atmosphere by more than
35% since the Industrial
Revolution. (National Oceanic and
Global Warming: The Greatest Threat © 2006 Deborah L. Williams
Atmospheric Administration 2006)
 The most carbon dioxide in
(CO2)
650,000 years. (IPCC 2007)
 Jan 2011 – 390.67 PPM
Jan 2012 – 392.76 PPM
 80% of all greenhouse gas
emissions
(National Library of Medicine)
10,000 BC
2009
CO2 in Atmosphere and Temperature
Note variation vs. local change
CO2 in Atmosphere and Temperature
Temperature Predictions
.