1934 - Richard Tolman shows
that blackbody radiation
in an expanding universe cools but remains thermal
1941 - Andrew McKellar
uses the excitation of CN doublet lines to measure that the "effective temperature
of space" is about 2.3 K
1948 - George
Gamow, Ralph Alpher, and Robert Herman predict that a Big
Bang universe will have a blackbody cosmic microwave background with temperature
about 5 K
1955 - Tigran Shmaonov
finds excess microwave emission with a temperature of roughly 3 K
advertisement
1964 - A. G. Doroshkevich
and Igor
Dmitrievich Novikov write an unnoticed paper suggesting microwave searches
for the blackbody radiation predicted by Gamow, Alpher, and Herman
1965 - Arno
Penzias, Robert
Wilson, Bernie Burke, Robert Dicke, and James Peebles discover the cosmic
microwave background radiation
1966 - Rainer Sachs and
Arthur Wolfe theoretically predict microwave background fluctuation amplitudes
created by gravitational potential variations between observers and the last
scattering surface (see Integrated
Sachs Wolfe effect)
1968 - Martin Rees and
Dennis Sciama theoretically predict microwave background fluctuation amplitudes
created by photons traversing time-dependent potential wells
1969 - R. A. Sunyaev and
Yakov Zel'dovich study the inverse Compton
scattering of microwave background photons by hot electrons
1990 - The Cosmic
Background Explorer (COBE)
satellite shows that the microwave background has a nearly perfect blackbody
spectrum and thereby strongly constrains the density of the intergalactic
medium
1992 - The COBE
satellite discovers anisotropy
in the cosmic microwave background
2003 - the WMAP
satellite produces a high resolution map of the cosmic microwave background.
