“The Sun”

1. “The Sun” • I Life Cycle of the Sun: A. Stars are born in nebulas. B. Nebula- A rapidly condensing cloud of gas and dust. C. Star “Pre-life Steps” 1. Gases rapidly condense to star dust. 2. Masses form 3. Masses collide with others to form larger pieces of “star stuff”. 4. Gravitational forces increase.

2. 5. This sets off a “snow ball effect” or chain reaction. 6. One very large object collects most of the “star stuff”. 7. Density increases. 8. Temperature increases. 9. Fusion begins to take place. a.) Fusion- The process in which two atoms fuse together to form another substance. b.) In the suns case there were two atoms of Hydrogen, which fused together to form Helium. 10.When fusion out put becomes balanced with the gravity of the large object, a star is born.

3. A. Main Sequence- The beginning phase of life for all stars. • II. Life Cycle Steps: 1. Every Star has a main sequence. 2. The star spends most of its life in this phase. 3. Fusion continues for billions of years. 4. When a star’s hydrogen begins to run out, the star begins to enter its next phase. B. Red Giant Phase- Beginning stage of death for small & medium size stars. 1. The fusion and gravity of a star becomes unbalanced do to hydrogen running out. 2. This makes the star collapse in on it self.

4. 3. Another round of fusion is triggered. This time helium fusses together. 4. The star swells to several times its original size 5. Remaining gas floats way as the star cools. C. White Dwarf- The remaining core of a small or medium star after the red giant phase is over. 1. The stars weight during the red giant phase will make the star collapse in on it-self. 2. All that is left of the star now is a collapsed core. 3. About the size of earth. D. Black Dwarf- The final stage of death of a small or medium size star.

5. 1. After the stars core cools enough that its luminosity is zero a star enters this phase of life. 2. All that is left is a tiny ball of “lifeless material” • III. Properties of the Sun: A. Size: 1. More than 99% of all matter in our solar system is in the sun. 2. About 110 times the diameter of the earth 3. The sun could hold more than a million earths. 4. The mass of the sun is 745 x greater than all of the planets put together.

6. B. Distance: 1. Earth is 1 AU away from the sun. (93 million miles) • IV. Layers of the Sun: 2. Light takes about 8 min. and 20 sec. to reach earth. C. Temperature: 1. Interior temperatures can be as high as 15 million degrees C. 2. Atmosphere temperatures can be as high as 6,000 degrees C. A. Core: 1. The area where the sun makes its energy.

7. 2. Nicknamed the sun’s power plant. 3. Where all of the sun’s fusion takes place. B. Photosphere: 1. First layer of the sun’s atmosphere. 2. Often called the “sun’s surface”. 3. Layer of the sun in which light is given off. C. Chromosphere: 1. The outer, less dense, layer of the sun’s atmosphere. 2. Red in color due to cooler temperatures. 3. Solar Flares take place there. a.) Solar Flare- gases, near sun spots, that shoots outward, at high speeds.

8. D. Corona: 1. Outer most layer of the sun. 2. Can only be seen during a solar eclipse. 3. Will damage your eyes if you look at the solar eclipse without protective eye ware. 4. Solar wind takes place here. a.) Solar wind- electrical charged particles that escape from the sun’s corona. 5. Both the solar wind and solar flares are responsible for Aurora Borealis. a.) Aurora Borealis- When earth’s atmosphere interacts with the particles from solar flares and solar wind, beautiful colors of light glow in the sky. b.) Sometimes called the Northern Lights.

9. A. What are sunspots? 1. Sunspots- areas of the photosphere that appear to be dark because they are cooler than the areas around them. • V. Sunspots: 2. We learned that the sun rotates by studying sunspots. 3. They can appear and disappear at times. 4. A sunspot maximum will take place every 10 to 15 years. 5. Some data suggest that this may have an effect on earth’s weather. 6. No data has ever confirmed that this pattern effects anything on earth.