AST101H1 Chapter Notes - Chapter 14: Maunder Minimum, Photon, Subatomic Particle
21 Oct 2012
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AST101H1 Full Course Notes
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14. 1 a closer look at the sun. The sun"s energy is absolutely vital to human existence. Late 19th century: the sun generates energy by slowly contracting in size: gravitational contraction. Shrinking gas clouds heat up because some of the gravitational potential energy of gas particles far from the cloud is converted into thermal energy as the gas moves inwards. A gradually shrinking sun would always have some gas moving inward, converting gravitational potential energy into thermal energy. This thermal energy would keep the inside of the sun hot. Because of its large mass, the sun would need to contract only very slightly each year to maintain its temperature- so slightly that the contraction would have been unnoticeable to 19th century astronomers. Shows that mass itself contains an enormous amount of potential energy. Calculations show that the sun"s mass contained more than enough energy to account for billions of years of sunshine.
