Important Epochs, Detail
	• Radiation-Dominated Era: – Compton Scattering is an important process that couples matter and radiation pre/post recombination (same temperatures). – Exchange of energy between radiation and matter in these states much studied. – Text shows heating of electrons by Compton scattering of photons of the microwave background radiation couples temperatures coupled throughout the era, and until z = 550 h2/5 Ω01/5.