1. Our Sun 16 October 2003

2. Today: Basic facts about the sun Solar details: Granulation, sunspots, magnetic fields, flares, prominences, corona, solar wind What is the sun made of?

3. Basic facts about the Sun Distance from earth: 150 million km (400 x as far as moon) Angular diameter: 1/2 degree (same as moon) True diameter: 110 x earth’s diameter Mass: 330,000 times earth’s mass Average density: 1.4 times that of water Intensity of sunlight at earth’s location: 1400 watts per square meter Total power output: 3.9 x 10 26 watts Surface temperature: 5800 K Made of ionized gases

4. Basic facts about the Sun Distance from earth: 150 million km (400 x as far as moon) measured using radar Angular diameter: 1/2 degree (same as moon) True diameter: 110 x earth’s diameter (400 x moon’s) Mass: 330,000 times earth’s mass gravity! Average density: 1.4 times that of water mass/volume Intensity of sunlight at earth’s location: 1400 watts per square meter measure directly Total power output: 3.9 x 10 26 watts calculate Surface temperature: 5800 K from power or spectrum Made of ionized gases too hot for anything else!

5. Sunspots, Granulation

6. Electromagnetism The sun is made of ionized atoms and electrons -- electrically charged particles Charged particles in motion create magnetic fields Magnetic fields can “trap” electrically charged particles (which can move parallel to the field but can’t go far in perpendicular directions)

7. Magnetic activity around sunspots

9. Solar Prominences

11. The Solar Corona

12. The Solar Corona and Solar Wind

13. What is the sun made out of? 74% hydrogen 25% helium 1% all other elements (oxygen, carbon, nitrogen, neon, aluminum, silicon, iron,... )

14. The Periodic Table Masses and rarities increase (mostly) toward the bottom of the table.