Cosmic microwave background3/24/2023 ![]() This continued until the universe had cooled sufficiently for stable atoms of hydrogen to form for the first time. The matter would reemit the radiation, but the radiation quickly was reabsorbed and reemitted. For the first few hundred thousand years, the radiation in the universe could not travel very far before being absorbed by matter. During subsequent adiabatic expansion, both the density and temperature of the universe had to decrease. This is a qualitative prediction, and creationists ought not to quibble over the modest range in the early quantitative temperature estimates or that the actual CMB temperature is slightly below the range.Īccording to the big bang model, the universe suddenly appeared in a very hot, dense, expanding state. The important thing is that the big bang theory predicted that the universe ought to be permeated by low-temperature blackbody radiation. Among the uncertainties were the expansion rate (and hence the age) and the density of the universe. The range in these estimates stemmed from the many uncertainties in the big bang model of that time (the model was new, and the name “big bang” wasn’t even coined by Sir Fred Hoyle until 1950). Recent creationists sometimes note that the temperature of the CMB is less than any values that had been predicted prior to its discovery, and hence conclude that the CMB is not evidence of the big bang. (1965) computed a rough upper limit of 40K for the CMB. In conjunction with the publication of Penzias and Wilson, Dicke et al. Gamow (1952) estimated a temperature of 50K, but later he calculated a temperature of 6K (Gamow 1956). 1 Shortly thereafter Alpher and Herman (1948b) estimated the CMB temperature to be 5K, but two years later they revised it to 28K (Alpher and Herman 1950). ![]() ![]() The prediction of the CMB usually is attributed to George Gamow in 1948, but proper credit ought to go to Alpher and Herman (1948a). Penzias and Wilson (1965) discovered the CMB in 1964, and they received the 1978 Nobel Prize in Physics in recognition for this work. The Cosmic Microwave Background (CMB) is generally regarded as the best evidence for the big bang theory. Keywords: big bang, blackbody, Cosmic Microwave Background Introduction ![]()
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