1. Our Sun

2. Why do we care about the Sun... - Light, heat, life - Space weather solar wind (1,000,000 mph) flares (UV, x-ray radiation) disturb Earth's magnetic field → power surges excess radiation bad for satellites

3. Why do we care about the Sun... - Light, heat, life - Space weather solar wind (1,000,000 mph) flares (UV, x-ray radiation) disturb Earth's magnetic field → power surges excess radiation bad for satellites -...one day it's gonna get us

4. Layers of the Sun

5. Core - very very hot (15 million K) - thermonuclear fusion (H → He) - 4 million tons of matter per second converted to energy

6. Radiative Zone - heat transfer through radiation (surprise!) - photons are absorbed and re-emitted: “random walk” - few 100,000 years

7. Convective Zone - heat transfer through convection (another surprise!) - granulation - core → surface: ~ 1 million years

8. Bright areas: hot pockets of gas move up Dark lanes: cool pockets of gas sink down Convection -- Granulation

9. Smaller granules join together, expand, and then split up. Granules

10. Atmosphere - photosphere: what you see! (sunspots, granulation) - the “surface”

11. Atmosphere - chromosphere: lower atmosphere - we can see it during eclipses

12. Atmosphere - corona: upper atmosphere - very hot, tenuous gas - we can see it during eclipses

13. Atmosphere - corona: upper atmosphere - very hot, tenuous gas - we can see it during eclipses

14. The corona is really hot, and no one knows why. (It’s 250x hotter than the surface of the sun!)...Magnetic field ?

15. Sunspots

16. Strong magnetic fields block convection cells → cooler areas (darker) Sunspots

17. - on the photosphere - formed by differential rotation ~equator: 25-day period ~poles: 35-day period

18. Sunspots - on the photosphere - formed by differential rotation ~equator: 25-day period ~poles: 35-day period - they're picky about location - high latitude → low latitude - “butterfly diagram”

19. Sunspots 11-year Solar Cycle

20. Prominences loops of gas

21. Flares eruptions of gas near sunspots

22. Coronal Mass Ejection (CME) ejected bubbles of gas

23. Charged particles interact with Earth’s magnetic field. Northern Lights

24. Particles in Earth’s atmosphere get excited.