Astronomy 1021 Lecture Notes - Lecture 11: Inverse-Square Law, Angular Diameter, Fusion Power
12 Dec 2018
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Document Summary
Big ball of hot gas held together by its own gravity. Energy travels outward until it eventually escapes the surface. Distance was rst measured using transits of venus. Angular diameter and distance = actual diameter of the sun. Newtons version of keplers laws: distance and orbital period = mass of sun. Brightness at earth and inverse square law = luminosity. Primary made up of hydrogen and helium (98% of suns mass) If we could capture 1 second of the suns luminosity we would be able to meet current human energy demands. Source of the suns energy is nuclear fusion. Contraction - gravitational potential energy - converted into kinetic energy of particles - temp rises. E = mc^2 : 1 kg of matter to energy would generate 100 000 trillion watts of energy. Nuclear ssion: splits heavy nucleus into smaller nuclei, used in power plants. Nuclear fusion: combines small nuclei into a larger nucleus.
