The size of bouncing lumps of charged particles, DM and photons in the primordial universe is supposed to be around 220,000 lyr (= sound horizon since the acoustic speed is approx 0.6c). If we then calculate the angle A subtended at earth by a lump of this size W, some 13.8 Glyr away D (back at recombination when t=380,000 yrs), then we are supposed to get A=1 degree. This is the fundamental size of the first acoustic peak in the CMB power spectrum.(adsbygoogle = window.adsbygoogle || []).push({});

If I put A=W/D radians, I don't get 1 degree when converting to degrees - why? It is suspiciously out by a factor of z=1100 - is this why

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# The first CMB peak - Flat Universe

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