1. Sun Nuclear Reactions If the mass in the center of the solar nebula is large enough, gravity will collapse more and more material, producing higher and higher pressures, producing higher and higher temperatures as a result of higher and higher energies of the particles in the gas. The high energies break apart any elements, resulting in the region of the protostar being composed mostly of hydrogen gas.

2. The work of Einstein – A new view of mass: Mass: A highly concentrated form of energy. E = m c 2 Sun Nuclear Physics

3. The work of Einstein – A new view of mass: E = m c 2 Therefore: All previous arguments about energy, including conversions and conservation must hold for mass-energy as well as kinetic energy and potential energy. Implication – mass can be converted to energy and energy can be converted to mass. Sun Nuclear Physics

4. The work of Einstein – A new view of mass: Mass: A highly concentrated form of energy. E = m c 2 Note: c is a VERY large number, and c 2 is HUGE. Therefore, a small amount of mass can be converted to a LARGE amount of energy. MASS conversion is the source of the energy produced in the core of the sun. Sun Nuclear Physics

5. Sun Nuclear Physics How much mass would be required to operate a 500 Megawatt power plant for one year? Note: The total amount of energy required to operate the facility for a year is 1.6 x 10 16 Joules. Solution: m c 2 = 1.6 x 10 16 Joules m = 1.6 x 10 16 (3 x 10 8 ) 2 1.6 x 10 16 9 x 10 16 =.177 kg = 177 g = Note: the mass of a paperclip is about 1 g

6. The Protostar Gravitational Collapse

7. The Protostar Gravitational Collapse Gravitational collapse causes an increase in pressure at the center of the protostar

8. The Protostar Gravitational Collapse High pressures strip electrons from nuclei, and break nuclei apart so that the interior is composed primarily of hydrogen

9. The Strong Force Puzzle: Nuclei should not be able to exist. Reason: The electrical force of repulsion between the protons should cause the nucleus to fly apart.

10. The Strong Force Puzzle: Nuclei should not be able to exist. Reason: The electrical force of repulsion between the protons should cause the nucleus to fly apart. Proposal: There is another force, called the Strong Force, which negates electrical repulsion over VERY short distance (the size of a nucleus).

11. The Strong Force Proposal: There is another force, called the Strong Force, which negates electrical repulsion over VERY short distance (the size of a nucleus). If protons can physically get close enough (not easy to do because of electrical repulsion) this strong force will dominate and allow the protons to “bind” and form a nucleus.

12. The Protostar Gravitational Collapse Once high enough, the high pressures can cause protons to overcome electrical repulsion, and get close enough to “bind” that is, the high pressure can trigger nuclear reactions

13. Sun Nuclear Physics – The Sun’s Core The solar nuclear reactions: The intermediate steps - 1 H + 1 H  2 H + proton + neutrino 2 H + 1 H  3 He + energy 3 He + 3 He  4 H + 1 H + 1 H + energy

14. Sun Nuclear Physics – The Sun’s Core The solar nuclear reactions: The net result - 4 ( 1 H )  4 He + energy + 2 neutrinos

15. Sun Nuclear Physics – The Sun’s Core The solar nuclear reactions: The net result - 4 ( 1 H )  4 He + energy + 2 neutrinos Mass of 1 H = 1.6736 x 10 -27 Kg Mass of four 1 H = 6.6943 x 10 -27 Kg Mass of 4 He = 6.6466 x 10 -27 Kg  m = 4.77 x 10 -29 kg Energy =  m c 2 = 4.3 x 10 -12 Joules per reaction

16. Sun Nuclear Physics – The Sun’s Core Solar data: Luminosity (amount of energy per second in watts) = 4 x 10 26 W Therefore, in one second the sun produces 4 x 10 26 J of energy (this is a big number).

17. Sun Nuclear Physics – The Sun’s Core Therefore, in one second the sun produces 4 x 10 26 J of energy (this is a big number). For the sun to produce this much energy requires Number of reactions = total energy per second/energy per reaction = (4 x 10 26 J/sec) / 4.3 x 10 -12 Joules/reaction = 9.3 x 10 37 reactions per second

18. Sun Nuclear Physics – The Sun’s Core Therefore, in one second the sun produces 4 x 10 26 J of energy (this is a big number). Also, 1 kg of mass is equivalent to 9 x 10 16 J (from E = m c 2 ) Therefore, the sun is converting (4 x 10 26 J/sec) / (9 x 10 16 J/Kg) = 4.4 x 10 9 kg/sec !!!

19. Sun Nuclear Physics – The Sun’s Core

20. Sun Nuclear Physics