Lecture 12: As Long as the Sun Shines

How long can the Sun continue to shine, and what source of energy does it tap to keep shining? This lecture answers this question by introducing two important energy sources for stars: Gravitational Contraction otherwise known as the Kelvin-Helmholz Mechanism, and Nuclear Fusion. We will show that fusion of 4 Hydrogen nuclei into a Helium nucleus via the proton-proton chain liberates enough energy to provide for the Sun's Luminosity needs for about 10 Billion Years. Recorded 2006 January 19 in 1008 Evans Laboratory on the Columbus campus of The Ohio State University. Note: the recording mistakenly says January 18th. Oops.