A Measurement of Excess Antenna Temperature at 4080 Mc/s
Penzias and Wilson reported that the 20-foot horn-reflector antenna at Bell Telephone Laboratories in Holmdel, New Jersey, measured an excess zenith antenna temperature of about 3.5 K at 4080 Mc/s (4.08 GHz) that could not be attributed to known sources of noise. They found this excess radiation to be isotropic, unpolarized, and free of seasonal variation within their measurement limits. In a companion paper, Dicke and colleagues interpreted this signal as relic radiation from a hot early universe, and it is now recognized as the discovery of the cosmic microwave background, providing key observational support for the Big Bang model.