ASTR 1200 Chapter Notes - Chapter 10: Energy Economics, Chromosphere, Solar Core
9 Sep 2015
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10. 1 a closer look at the sun: in the middle of the 19th century, scientists started looking into how the sun shines. It was originally thought that it was composed of burning wood or coal, but that didn"t produce enough energy: a more plausible idea was gravitational contraction, the sun generating energy by contracting in size. Watts are the standard power unit at one joule of energy per second. Most of it"s radiation comes from the middle layer of it"s solar atmosphere, the chromosphere. Energy moves outward here, usually as photons: the sun"s energy comes from the core and nuclear fusion turns hydrogen into helium. It is about 15 million k in the core. 10. 2 nuclear fusion in the sun: the only force in nature that can overcome electromagnetic repulsion between to positive nuclei is strong force. These can be seen on the surface by looking for doppler shifts.
