<Li> 1953--Erwin Finlay - Freundlich in support of his tired light theory, derives a blackbody temperature for intergalactic space of 2.3 K with comment from Max Born suggesting radio astronomy as the arbitrator between expanding and infinite cosmologies . </Li> <Ul> <Li> 1941--Andrew McKellar detected the cosmic microwave background as the coldest component of the interstellar medium by using the excitation of CN doublet lines measured by W.S. Adams in a B star, finding an "effective temperature of space" (the average bolometric temperature) of 2.3 K </Li> <Li> 1946--George Gamow calculates a temperature of 50 K (assuming a 3 - billion year old universe), commenting it "...is in reasonable agreement with the actual temperature of interstellar space", but does not mention background radiation . </Li> <Li> 1948--Ralph Alpher and Robert Herman estimate "the temperature in the universe" at 5 K . Although they do not specifically mention microwave background radiation, it may be inferred . </Li> <Li> 1949--Ralph Alpher and Robert Herman re-re - estimate the temperature at 28 K . </Li> <Li> 1953--George Gamow estimates 7 K . </Li> <Li> 1956--George Gamow estimates 6 K . </Li> <Li> 1955--Émile Le Roux of the Nançay Radio Observatory, in a sky survey at λ = 33 cm, reported a near - isotropic background radiation of 3 kelvins, plus or minus 2 . </Li> <Li> 1957--Tigran Shmaonov reports that "the absolute effective temperature of the radioemission background...is 4 ± 3 K". It is noted that the "measurements showed that radiation intensity was independent of either time or direction of observation...it is now clear that Shmaonov did observe the cosmic microwave background at a wavelength of 3.2 cm" </Li> <Li> 1960s--Robert Dicke re-estimates a microwave background radiation temperature of 40 K </Li> <Li> 1964--A.G. Doroshkevich and Igor Dmitrievich Novikov publish a brief paper suggesting microwave searches for the black - body radiation predicted by Gamow, Alpher, and Herman, where they name the CMB radiation phenomenon as detectable . </Li> <Li> 1964--65--Arno Penzias and Robert Woodrow Wilson measure the temperature to be approximately 3 K. Robert Dicke, James Peebles, P.G. Roll, and D.T. Wilkinson interpret this radiation as a signature of the big bang . </Li> <Li> 1966--Rainer K. Sachs and Arthur M. Wolfe theoretically predict microwave background fluctuation amplitudes created by gravitational potential variations between observers and the last scattering surface (see Sachs - Wolfe effect) </Li> <Li> 1968--Martin Rees and Dennis Sciama theoretically predict microwave background fluctuation amplitudes created by photons traversing time - dependent potential wells </Li> <Li> 1969--R.A. Sunyaev and Yakov Zel'dovich study the inverse Compton scattering of microwave background photons by hot electrons (see Sunyaev - Zel'dovich effect) </Li> <Li> 1983--Researchers from the Cambridge Radio Astronomy Group and the Owens Valley Radio Observatory first detect the Sunyaev - Zel'dovich effect from clusters of galaxies </Li> <Li> 1983--RELIKT - 1 Soviet CMB anisotropy experiment was launched . </Li> <Li> 1990--FIRAS on the Cosmic Background Explorer (COBE) satellite measures the black body form of the CMB spectrum with exquisite precision, and shows that the microwave background has a nearly perfect black - body spectrum and thereby strongly constrains the density of the intergalactic medium . </Li> <Li> January 1992--Scientists that analysed data from the RELIKT - 1 report the discovery of anisotropy in the cosmic microwave background at the Moscow astrophysical seminar . </Li> <Li> 1992--Scientists that analysed data from COBE DMR report the discovery of anisotropy in the cosmic microwave background . </Li> <Li> 1995--The Cosmic Anisotropy Telescope performs the first high resolution observations of the cosmic microwave background . </Li> <Li> 1999--First measurements of acoustic oscillations in the CMB anisotropy angular power spectrum from the TOCO, BOOMERANG, and Maxima Experiments . The BOOMERanG experiment makes higher quality maps at intermediate resolution, and confirms that the universe is "flat". </Li> <Li> 2002--Polarization discovered by DASI . </Li> <Li> 2003--E-mode polarization spectrum obtained by the CBI . The CBI and the Very Small Array produces yet higher quality maps at high resolution (covering small areas of the sky). </Li> <Li> 2003--The Wilkinson Microwave Anisotropy Probe spacecraft produces an even higher quality map at low and intermediate resolution of the whole sky (WMAP provides no high - resolution data, but improves on the intermediate resolution maps from BOOMERanG). </Li> <Li> 2004--E-mode polarization spectrum obtained by the CBI . </Li> <Li> 2004--The Arcminute Cosmology Bolometer Array Receiver produces a higher quality map of the high resolution structure not mapped by WMAP . </Li> <Li> 2005--The Arcminute Microkelvin Imager and the Sunyaev - Zel'dovich Array begin the first surveys for very high redshift clusters of galaxies using the Sunyaev - Zel'dovich effect . </Li> <Li> 2005--Ralph A. Alpher is awarded the National Medal of Science for his groundbreaking work in nucleosynthesis and prediction that the universe expansion leaves behind background radiation, thus providing a model for the Big Bang theory . </Li> <Li> 2006--The long - awaited three - year WMAP results are released, confirming previous analysis, correcting several points, and including polarization data . </Li> </Ul> <Li> 1941--Andrew McKellar detected the cosmic microwave background as the coldest component of the interstellar medium by using the excitation of CN doublet lines measured by W.S. Adams in a B star, finding an "effective temperature of space" (the average bolometric temperature) of 2.3 K </Li> <Li> 1946--George Gamow calculates a temperature of 50 K (assuming a 3 - billion year old universe), commenting it "...is in reasonable agreement with the actual temperature of interstellar space", but does not mention background radiation . </Li>

Where does radiation in the universe come from