Feb6 - WHAT POWERS OUR SUN? Before ~1800: Gods? No one...

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Unformatted text preview: WHAT POWERS OUR SUN? Before ~1800: Gods? No one really thought about it! 1800-1850 or so: Chemical reactions? Burning coal?! – <Fuel> + O 2 ! CO 2 + H 2 O + energy (+ pollution) – Would burn out in just 10,000 years ~1850-1904 : Gravitational contraction? The Sun getting smaller will heat up – Compressing things heats them - e.g. bike pump gets warm – This is why Jupiter radiates more heat than it receives from the Sun, as Jupiter is still very slowly contracting – Maximum age 25 million years – Inconsistent with fossil record 1904: Einstein: E=mc 2 , matter converts to energy! E = energy equivalent of mass m = mass equivalent of energy c = speed of light (3x10 8 m/s) – Basic energy source realized – But no idea how to make it work – With c 2 so huge, just a tiny bit of matter makes for vast energy 1930’s: Hydrogen fusion! 4H ! He + energy – Hans Bethe and C. F. von Weizsäcker – Sun made of Hydrogen (plenty of fuel) and Helium (the ‘ash’) – Electric repulsion (like charges repel) make it hard for two...
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This note was uploaded on 02/25/2011 for the course ASTR 1102 taught by Professor Staff during the Spring '08 term at LSU.

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Feb6 - WHAT POWERS OUR SUN? Before ~1800: Gods? No one...

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