1. The Sun

2. Introduction sun’s gravity is most powerful force in solar system Force so strong because of Sun’s mass 99.8 % of the mass of the solar system is the Sun Has an interior and atmosphere No solid surface-ball of glowing gas

3. Sun’s Interior like a giant furnace Energy comes from nuclear fission Nuclear Fission: hydrogen atoms join together to form helium Occurs only under high temperature Sun’s temperature at core=15 million degrees Celsius

4. There is enough hydrogen fuel in the core of the sun to last 10 billion years Sun about 5 billion years old

5. The Sun’s Atmosphere 3 layers: no boundaries between layers 1. Photosphere: inner layer (the layer we look at in a picture) 2. Chromosphere: middle layer-reddish glow around inner layer 3. Corona: white halo around sun – Only visible during eclipse or with special telescope

6. Features Sunspots: areas of gas on the sun that are cooler than the gases around them – Number of sunspots vary – Usually appear in pairs or groups Sunspot about as large as earth

7. Prominences: reddish loops of gas linking different parts of sunspot regions About 10,000 degrees Celsius http://www.nasa.gov/mission_pages/stereo/multimedia/Huge -Eruptive-Prominence.html http://www.nasa.gov/mission_pages/stereo/multimedia/Huge -Eruptive-Prominence.html

8. Solar Flares: explosion of hydrogen gas from the sun’s surface that occurs when loops in sunspot regions suddenly connect. Gases on sun heated to millions of degrees Celsius http://www.nasa.gov/mission_pages/sunearth/news/News021411-xclass.html