The EDGES Absorption Depth and the Limit on Residual Bounce Heating

The absorption depth reported by the EDGES experiment in 2018, roughly twice as deep as the deepest feature adiabatic cooling permits, remains contested. Using the stated cosmology and the brightness-temperature relations described in the Methods, the calculation gives the following headline values: standard depth mK = -267; edges depth mK = -500; required Ts K = 3.4; adiabatic Tg K = 6.0; ratio = 1.77. The comparison values taken from the published record — including the EDGES and SARAS reports, HERA limits and the Planck optical depth where relevant — are used exactly as published, and the bounce contribution enters only through the named timing, heating or shear inputs. The result is a computed prediction for the delayed-onset history, with its sensitivity to each input stated in the Discussion. This study is simulated and computed from stated assumptions; it is not a measurement.