Size meters time seconds ina8on solves atness problem

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Unformatted text preview: WMAP results are baryon/photon = 6.5x10- 10; book says 2x109 to 1) 5/30/13 UW, ASTR 323, SP13, Eric Agol ©2013 12 Neutron Abundance vs. Time / Temperature p + e- (n / p)eq ∝ exp(−Δmc 2 / kT ) ↔ n + νe … Δmc 2 = 1.29MeV Rates set by τn “Freeze – Out” BBN “Begins” n / p ∝ exp(−t / τ n ) β Decay 5/30/13 τ n = 885.7 ± 0.8 sec 13 Pre - BBN Only n & p 5/30/13 Post - BBN Mainly H & 4He UW, ASTR 323, SP13, Eric Agol ©2013 14 Big Bang theory predicts: 74- 75% H, 24- 25% He (by mass) Matches observa8ons the Sun 5/30/13 UW, ASTR 323, SP13, Eric Agol ©2013 “Big Bang Nucleosynthesis” predicts abundances of light elements: 4He, 3He, Deuterium (2H), 2Li rela8ve to hydrogen if density of...
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