1. CH. 29.1 – THE SUN Chapter 29 – March 13 th, 2015

2. VOCABULARY TO KNOW…  Photosphere –  Chromosphere –  Corona –  Convection Zone –  Radiative Zone –  Nuclear Fusion -

3. CONTENTS OF THE SUN  The sun is made up of…  75% Hydrogen  24% Helium  1% Other Gases  It is powered by FUSION = where lighter nuclei is combine to make heavier ones  Thus, releasing LOTS of ENERGY!

4. ** EACH STEP RELEASES ENERGY ** #1. 2 hydrogens ( protons) fuse, the second p + is neutralized by emitting a positron…so that proton becomes a neutron (p + n o pair created)

5. 2. Another H proton combines with the first p + n o pair…creates a helium isotope (2 p +, 1 n o )

6. 3. These helium isotopes, each with 2p + 1n o, fuse and release two protons leaving behind a “common” helium atom.

7. ** EACH STEP RELEASES ENERGY **

8. ABOUT ENERGY…  Neutrinos (uncharged “electrons”… 1/10,000 the size of an e - ) are also released and reach Earth in 8 minutes  Helium (He) product is 0.7% less massive than the Hydrogen (H) that formed it….  --that MASS is converted into ENERGY  THIS energy causes intense shine and heat.

9. MASS -> ENERGY  1905:  Nucleus of atom/fusion unknown…  Einstein proposed: small mass yields large energy  This is known as the Theory of Relativity  E=mc 2  Scientists used E=mc 2 to explain the sun’s huge quantities of E. E = mc² E = energy M = mass of matter changed C = speed of light

10. SUN’S STRUCTURE 1. Core  gaseous  25% of sun’s diameter  temp 15,000,000 o C)  Super dense (10x that of iron  heat & pressure cause atoms to separate into nuclei and e - s. (remember, nuclei are +)  Nuclei try to repel but heat/pressure force them to fuse.

11. 2. Radiative - Outside core  2-7,000,000 o C  E moving as EM waves 3. Convection (30% of Sun)  2,000,000 o C  E moving as convection (hot gases move out, expand, lose E…become dense and sink back down in convective zone…repeats) Corona is seen during solar eclipses

13. ATMOSPHERE OF THE SUN… 4. Photosphere  gases risen out of convective (6,000 o C) 5. Chromosphere  color sphere 6-50,000 o C g  as shoots up from photosphere 6. Corona  Temps. spikes here (above 1,000,000 o C)  ions can escape---this is solar wind.