PHYS 183 Lecture Notes - Lecture 13: Radiography, Convection Zone, Photosphere
21 Apr 2018
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Fission large nucleus decays into two more stable nuclei. Fusion two nuclei fuse into one larger nucleus. A nucleus that is less bound contains less binding energy, so fission of a less bound atom will result in two more bound atoms. Strong force: long range repulsion but short range attraction. Sun overcomes this problem easily: pressure, density at core of sun so large that nuclear fusion happens easily, hydrogen fused to helium. Makes sun most powerful furnace in solar system by far. Energy produced equivalent of burning 7000 kg of coal every hour on every square meter of the sun. U(cid:374)"s set of (cid:374)u(cid:272)lear rea(cid:272)tio(cid:374)s (cid:272)alled proton-proton chain. Start with two unbound hydrogen nuclei (2 protons) p+p. Step 1: fuse to produce deuterium: bound p+n: produce neutrino, positron in the process, this is because there are certain conservation laws that must be kept. Step 2: deuterium hits another proton, forms helium 3 (p+p+n)
