Notes
Outline
Slide 1
Facts about the Sun & Sunspots
Is 93 million miles from Earth
Is about a million miles across
Is just a huge ball of glowing gas – it’s not solid
Is 5 billion years old, another 5 billion to go
Is a medium-size star, one of about 2 billion in our galaxy
Is covered with sunspots, which come and go
At “Solar Max”, there are lots of spots
Solar Max was about four years ago
In two or three years, at “Solar Min”, there will be no spots!
Sunspots are BIG!
Sunspot history
Galileo’s drawings showed sunspots, & they moved!
Galileo made a drawing each day, in the summer of 1612.  Try to do this yourself this summer!
Here 36 drawings are put together into a “movie”.
How did Galileo know those spots were on the Sun?
Galileo used common sense to figure out that these dark spots were on the Sun, not planets or airplanes
Study how the shapes of the spots change as they move from the center of the Sun’s disk to the edge
The Sun would look a lot different
if your eyes could see X-rays!
If your eyes could see X-rays, you would not see sunspots.  You would see the Sun’s corona.
What Galileo didn’t know:
The Sun rotates faster near its Equator
Equator: 25 days
Pole: 35 days
The Sun’s magnetic field gets all twisted up, and then it erupts
Scientists call these eruptions
Coronal Mass Ejections (CMEs)
A CME is a cloud of hot gas, weighing billions of tons, which erupts from the Sun at a speed up to millions of miles per hour.
CMEs occur almost every day, but most go off in other directions, not toward Earth.
CMEs busting out all over
This 16-day sequence during a very active period shows that CMEs happen often and they go in all directions.
S shapes in the X-ray corona
CMEs often come from regions shaped like an S or reverse-S.  The S shown here erupted several times during the two days of the movie clip.
S marks the spot animation
The S shapes store lots of energy.  A large CME releases about 100,000 times more energy than the world uses in a year.
How to recognize an Earth-bound CME
When CMEs hit Earth
Sometimes spacecraft get fried
Sometimes the power goes out
Sometimes beautiful auroras occur
    Often called the northern lights, these sometimes colorful light shows in the night sky can sometimes be seen from here in Montana.
How can we prepare for CMEs?
improve space weather monitoring & predictions
conduct research on the Sun-Earth connection
build stronger satellites and more protected systems
take operational precautions in response to warnings
Web sites about Solar Max
Sunspots and the Solar Cycle
http://www.sunspotcycle.com
• about sunspots, solar flares, and the latest news about the solar cycle.
NOAA’s Space Environment Center
http://www.sec.noaa.gov/Education/
• about current weather conditions in space near Earth, and more – the how and why of the effects of the Sun on Earth.
Solar Storms and Their Human Impacts
http://image.gsfc.nasa.gov/poetry/storms/storms.html
• about effects of solar storms on satellites and power systems
Max Millennium page at MSU - Bozeman
http://solar.physics.montana.edu/max_millennium/press
• a page of links to these and many other sites