1. © 2010 Pearson Education, Inc. Chapter 14 Our Star

2. © 2010 Pearson Education, Inc. Why does the Sun Shine?

3. © 2010 Pearson Education, Inc. Is it on FIRE?

4. © 2010 Pearson Education, Inc. Is it on FIRE? Luminosity ~ 10,000 years Chemical energy content

5. © 2010 Pearson Education, Inc. Is it on FIRE? …NO! Luminosity ~ 10,000 years Chemical energy content

6. © 2010 Pearson Education, Inc. Is it CONTRACTING? Insert TCP 6e Chapter 14 opener

7. © 2010 Pearson Education, Inc. Is it CONTRACTING? Luminosity Gravitational potential energy ~ 25 million years

8. © 2010 Pearson Education, Inc. Is it CONTRACTING?...NO! Luminosity Gravitational potential energy ~ 25 million years

9. © 2010 Pearson Education, Inc. Why does the Sun shine?

10. © 2010 Pearson Education, Inc. Weight of upper layers compresses lower layers. Insert TCP 6e Figure 14.1

11. © 2010 Pearson Education, Inc. Gravitational equilibrium: There is a balance between the outward fusion pressure and the inward pressure, due to gravity.

12. © 2010 Pearson Education, Inc. What is the Sun’s structure? Insert TCP 6e Figure 14.3

13. © 2010 Pearson Education, Inc. Solar wind: A flow of charged particles from the surface of the Sun

14. © 2010 Pearson Education, Inc. Corona: Outermost layer of solar atmosphere and seen only during a total solar eclipse. ~1 million K

15. © 2010 Pearson Education, Inc. Chromosphere: Middle layer of solar atmosphere and seen only during a total solar eclipse. ~ 10 4 –10 5 K

16. © 2010 Pearson Education, Inc. Photosphere: Visible surface of Sun ~ 6000 K

17. © 2010 Pearson Education, Inc. Convection Zone: Energy transported upward by rising hot gas

18. © 2010 Pearson Education, Inc. Radiation Zone: Energy transported upward by photons

19. © 2010 Pearson Education, Inc. Core: Energy generated by nuclear fusion ~ 15 million K

20. © 2010 Pearson Education, Inc. Clicker Question What is the surface we see? A.corona B.photosphere C.chromosphere D.solar wind

21. © 2010 Pearson Education, Inc. Clicker Question What is the surface we see? A.corona B. photosphere C.chromosphere D.solar wind

22. © 2010 Pearson Education, Inc. Clicker Question What layer is the hottest? A.corona B.photosphere C.chromosphere

23. © 2010 Pearson Education, Inc. Clicker Question What layer is the hottest? A. corona B.photosphere C.chromosphere

24. © 2010 Pearson Education, Inc. Clicker Question What layer is the coolest? A.corona B.photosphere C.chromosphere

25. © 2010 Pearson Education, Inc. Clicker Question What layer is the coolest? A.corona B. photosphere C.chromosphere

26. © 2010 Pearson Education, Inc. How does nuclear fusion occur in the Sun?

27. © 2010 Pearson Education, Inc. Fission Big nucleus splits into smaller pieces. (Example: nuclear power plants) Fusion Small nuclei stick together to make a bigger one. (Example: the Sun, stars)

28. © 2010 Pearson Education, Inc. High temperatures enable nuclear fusion to happen in the core.

29. © 2010 Pearson Education, Inc. The Sun releases energy by fusing four hydrogen nuclei into one helium nucleus.

30. © 2010 Pearson Education, Inc. The proton–proton chain is how hydrogen fuses into helium in Sun.

31. © 2010 Pearson Education, Inc. IN 4 protons OUT 4 He nucleus 2 gamma rays 2 positrons 2 neutrinos Total mass is 0.7% lower.

32. © 2010 Pearson Education, Inc. Proton-Proton Chain in Gory Detail Step 1: 1 H 1 + 1 H 1 --> 2 H 1 + e + + 1 H 1 is a hydrogen nucleus - subscript is the number of protons in nucleus, superscript is the number of protons + neutrons in the nucleus. Hydrogen nucleus has 1 proton, 0 neutrons. 2 H 1 is a deuterium nucleus (hydrogen isotope) with 1 proton and 1 neutron in nucleus. e + is a positron or antiparticle of the e -. When e + and e - meet, e + + e - __ > 2   two gamma rays are produced  is a neutrino and helps to carry away energy. Step 2: 1 H 1 + 2 H 1 --> 3 He 2 +  3 He 2 is a helium isotope,  is a gamma ray. Step 3: 3 He 2 + 3 He 2 --> 4 He 2 + 1 H 1 + 1 H 1 4 He 2 is ordinary or ‘balloon’ helium.

33. © 2010 Pearson Education, Inc. Clicker Question What is e + ? A.electron B.positron C.Neutron D.proton E.neutrino

34. © 2010 Pearson Education, Inc. Clicker Question What is e + ? A.electron B.positron C.Neutron D.proton E.neutrino

35. © 2010 Pearson Education, Inc. Clicker Question What is 2 H 1 ? A.gamma ray B.helium nucleus C.deuterium nucleus D.ordinary hydrogen nucleus

36. © 2010 Pearson Education, Inc. Clicker Question What is 2 H 1 ? A.gamma ray B.helium nucleus C.deuterium nucleus D.ordinary hydrogen nucleus

37. © 2010 Pearson Education, Inc. Clicker Question What is ? A.gamma ray B.positron C.Neutron D.proton E.neutrino

38. © 2010 Pearson Education, Inc. Clicker Question What is ? A.gamma ray B.positron C.Neutron D.proton E.neutrino

39. © 2010 Pearson Education, Inc. Clicker Question What is  ? A.gamma ray B.positron C.Neutron D.proton E.neutrino

40. © 2010 Pearson Education, Inc. Clicker Question What is  ? A.gamma ray B.positron C.Neutron D.proton E.neutrino