1. 24.3 – The Sun

2. *Interior *Visible Surface/ Photosphere *Atmosphere

3. Interior Cannot be observed directly Produces energy by nuclear fusion Made entirely of gases Core incredibly hot (15 million degrees C), high-pressure area where fusion takes place to create light and energy Radiation Zone Energy from the core moves towards the surface over the course of 10,000 years Convection Zone Circular convection currents cycle energy from hotter center to cooler surface

4. Visible Surface or Photosphere 90% H, 10% He Still a gas, not a solid 500 km thick Grainy texture called granules. Brightness is related to hotter gases rising from below (convection currents). They cool, darken, and then sink below again every 10-20 minutes.

5. Granules: https://www.youtube.com/watch?v=W_Scoj4HqCQ

6. Atmosphere Only visible during eclipse Chromosphere – Thinner layer of gases above Photosphere (same stuff, just at less pressure and density) – Emits red light, rather than yellowish/orange glow of Photosphere b/c it is cooler Corona – “Ionized” gases thinner than chromosphere – Some ions can escape the gravitational pull of sun

7. Eclipse: https://www.youtube.com/watch?v=RQiU1VlMgFI