- #1
eherrtelle59
- 25
- 0
If we know that the temperature of photons was apprx. 3000 K at recombination and the temperature of the CMB is apprx. 2.725 K today, how can we extrapolate the value of the scale factor at recombination?
I know that recombination happens at a matter-dominated era, such that the density goes a^-3 ****(not a^-4) and that at this era a(t) goes t^2/3
But this doesn't tell me how a(t) is related to temperature...
I know that recombination happens at a matter-dominated era, such that the density goes a^-3 ****(not a^-4) and that at this era a(t) goes t^2/3
But this doesn't tell me how a(t) is related to temperature...
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