1 The Sun Our star - inside and out

2 Earth having a really, really bad day.

3 Explain the proton-proton cycle in easy-to- understand language. State how radiation is transported through each region of the Sun’s interior Explain how the Sun maintains a constant balance in its interior (solar thermostat) Learning Goals:

4 LIGHT!

5 1 H + 1 H --> 2 H + e + + neutrino 2 H + 1 H --> 3 He + gamma ray 3 He + 3 He --> 4 He + 1 H + 1 H Core  Must occur twice Explain the proton-proton cycle in easy-to-understand language. Proton-Proton Cycle of original mass is converted to energy e-e- 

6 Protons must collide at high velocities: Temperature must be > 10,000,000 Kelvin Plasma must be extremely dense. + + I hate you, proton. You are so repulsive. You reek! Stay away, you positive jerk. Explain the proton-proton cycle in easy-to-understand language.

7 a.Two helium-3 nuclei collide and fuse to form the more common form of the element: helium-4. b. At the instant the nuclei fuse and create a deuterium nucleus, a positron and a neutrino are created. c. Two protons (H nuclei) meet under the extreme conditions present in the core of the Sun. d. Positron + electron = annihilation; masses convert to energy in form of 2 gamma ray photons. e. Two extra protons are released, available for further nuclear reactions. f. In about 6 seconds a 3rd proton fuses with deuterium nucleus to form He-3 + gamma ray.

8 PASS YOUR SHEETS TO THE CENTER AISLE DEMONSTRATION OF THE RANDOM WALK WILL TAKE PLACE WHILE YOU ARE HANDING IN YOUR SHEETS.

9 Random Walk State how radiation is transported through each region of the Sun’s interior Radiative Zone

10 CONVECTION MOVIE State how radiation is transported through each region of the Sun’s interior Granulation   Convection Zone

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12 State how radiation is transported through each region of the Sun’s interior

13 Another way of thinking about this: The Solar Thermostat The Solar Thermostat Explain how the Sun maintains a constant balance in its interior (solar thermostat) Hydrostatic (gravitational) equilibrium in the Sun maintains a constant balance between inward- pushing gravity and outward-pressing pressure.

14 Number of particles in core is decreasing. NET RESULT IN: 6 H OUT: 1 He + 2 H Explain how the Sun maintains a constant balance in its interior (solar thermostat)

15 Explain how the Sun maintains a constant balance in its interior (solar thermostat)