The Sun (continued)
Surface features vary with 11-year cycle:
- Sunspots: cooler with strong magnetic field,
- Solar flare: eruption from sunspot group,
- Convection cells, transporting energy outwards.
Energy produced by thermonuclear fusion of 4 H-atoms into He-atom at 8 million ƒC.
Solar Model well understood:
- Fusion in core about 1/4 solar radius in size,
- Neutrinos - 1/4 predicted number?