AST201H1 Chapter Notes - Chapter 14.1-14.2: Solar Luminosity, Nuclear Fusion, Solar Core

• School: UTSG
• Department: Astronomy & Astrophysics
• Course: AST201H1
• Professor: Michael Reid

Document Summary

Most ancient peoples thought of the sun as some type of fire (i. e. a lump of burning coal or wood): eventually ruled out because this could not account for it"s immense output of energy. Late 19th century belief was that the sun generated energy through gravitational contraction: gravitational contraction: the process in which gravity causes an object to contract, thereby converting gravitational potential energy into thermal energy. Conclusion was that the sun could shine up to 25m years through this process disproved this explanation because the earth was proved to be much older. 2 shows that mass itself contains an enormous amount of potential energy: if the sun could convert the energy to thermal energy, then the billions of years of sunshine could be explained. Nuclear fusion requires extremely high temperatures and densities found deep in the core of the sun. Two balances keeping the sun shining and its size/energy output stable: gravitational equilibrium.