2. The Sun : Our Closest Star

3. A. The Size of The Sun 1. The sun is a medium size star. 1. The sun is a medium size star. 99 % of ALL matter in our solar system is in the sun. 99 % of ALL matter in our solar system is in the sun. It is about 93 million miles from the Earth or 150 million kilometers. It is about 93 million miles from the Earth or 150 million kilometers. It takes 7.8 min. for light to get to Earth. It takes 7.8 min. for light to get to Earth.

4. A. The Size of the Sun The diameter of the sun is 864,000 miles The diameter of the sun is 864,000 miles ( 1. 39 million kilometers) Earth is 12,104 km in diameter ( the sun is 116 x BIGGER ! ) ( Earth =7,747 miles)

5. B. The Sun has LAYERS From the inside out: ( see p 679 ) From the inside out: ( see p 679 ) Core Core Radiation Zone Radiation Zone Convection Zone Convection Zone Photosphere Photosphere Chromosphere Chromosphere Corona Corona

6. B. Continued…Layers 1. Light comes from the Photosphere 1. Light comes from the Photosphere 2. The Corona is thousands of miles thick. 2. The Corona is thousands of miles thick. It’s temperature = 2,000,000 degrees C It’s temperature = 2,000,000 degrees C The temperature of the core is 15,000,000 Degrees C. The temperature of the core is 15,000,000 Degrees C.

7. B. The Sun has Layers:

8. C. Surface Features of The Sun Solar Flares Solar Flares Prominences Prominences Sun Spots Sun Spots

9. C. Surface Features of the Sun 1. Solar Flares = violent gas eruptions 1. Solar Flares = violent gas eruptions a. They cause damage to satellites, b. interfere with radio & T.V., c. and cause Aurora Borealis ( the Northern Lights). The Norse myth of the Valkaries Is connected to this. a. Gov. Web Gov. Web Gov. Web

10. C. Surface Features of the Sun 2. Prominences = huge columns of gas that fly out from the sun. 2. Prominences = huge columns of gas that fly out from the sun. They are thousands of miles long. They are thousands of miles long. UV & X-rays increase. UV & X-rays increase. Web Web Web

11. Prominences are HUGE

12. C. Surface Features… Sun Spots = Dark areas that are cooler parts on the sun’s surface. Sun Spots = Dark areas that are cooler parts on the sun’s surface. a. This shows that the sun ROTATES. b. Spots are not permanent. They last from days to months. c. The “sun spot maxima” occurs every 11 years.

13. D. Nuclear Fusion Occurs in the Sun’s Core Hydrogen atoms join to become Helium atoms. Hydrogen atoms join to become Helium atoms. This is a nuclear reaction ( not a chemical reaction. Chemical reactions involve electrons.) This is a nuclear reaction ( not a chemical reaction. Chemical reactions involve electrons.)

14. Video

15. E. NASA’s Tools For Studying the Sun Solar Probes Solar ProbesSolar ProbesSolar Probes SOHO Space Observatory (1.5 million km above Earth) SOHO Space Observatory (1.5 million km above Earth)Space Observatory Space Observatory The primary scientific aims of the Solar and Heliospheric Observatory mission (SOHO)