ASTRON 1F03 Lecture Notes - Lecture 16: Chromosphere, Gamma Ray, Solar Wind
18 Dec 2015
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Document Summary
Mass of 4h nuclei is slightly greater than 1 he nucleus. Relativity: mass and energy are equivalent (einstein"s famous relation): The strong nuclear force binds protons together if close enough. Fusion requires ramming protons together at high speed (i. e. , at high temperature). The sun has been around a long time: about 4. 6 billion years. The sun must therefore generate a lot of energy over a long time. Source: nuclear fusion of hydrogen to helium in the central core. This happens for all main-sequence stars: e = mc2, c = speed of light. Difference in mass is released as energy. Fusion takes place in the core, where it is hot enough. Begin with 4 hydrogen nuclei and end with a helium nucleus, and energy as well. Scientists have been trying to achieve fusion on earth. Unstable super hot gas is contained with strong magnetic fields. Costs about as much energy as it makes.
