It was predicted, then found accidentally. https://www.ifi.unicamp.br/~assis/Apeiron-V2-p79-84(1995).pdf https://www.ifi.unicamp.br/~assis/Apeiron-V2-p79-84(199

It was predicted, then found accidentally. https://www.ifi.unicamp.br/~assis/Apeiron-V2-p79-84(1995).pdf https://www.ifi.unicamp.br/~assis/Apeiron-V2-p79-84(1995).pd... gives a date of 1948 for the following (Ralph Alpher and Robert Herman): > The temperature of the gas at the time of condensation was 600 K., and the temperature in the Universe at the present time is found to be about 5 K. We hope to pub- lish the details of these calculations in the near future. https://en.wikipedia.org/wiki/Discovery_of_cosmic_microwave_background_radiation https://en.wikipedia.org/wiki/Discovery_of_cosmic_microwave_... describes the kinda-accidental confirmation of this theory.