Penzias and Wilson Discover Cosmic Microwave Background
May 20, 1964 · 20th Century
In 1964, Arno Penzias and Robert Wilson at Bell Laboratories detected a persistent, uniform background noise at approximately 3 Kelvin using the Holmdel Horn Antenna in New Jersey. After ruling out all terrestrial sources of interference, they learned their measurement matched theoretical predictions of remnant radiation from the early universe. Published in the Astrophysical Journal in 1965, the discovery of the cosmic microwave background provided direct observational evidence supporting the Big Bang model over the competing Steady State theory. Penzias and Wilson received the 1978 Nobel Prize in Physics.
Key Figures
Arno PenziasRobert Woodrow WilsonRobert Dicke
Locations
Bell LabsHolmdel Horn Antenna
Topics
astronomycosmologybig bangcosmic microwave backgroundradio astronomy
Connected Events — 3 Connections
Lemaître's expanding universe model mathematically predicted that the early universe would have been much hotter and denser, laying theoretical groundwork that later enabled physicists to predict the existence of cosmic microwave background radiation that Penzias and Wilson discovered Lemaître Proposes Cosmic Expansion Theory
CMB discovery and dark matter evidence together reshaped cosmological models of the universe's composition Vera Rubin Publishes Galaxy Rotation Evidence for Dark Matter
The 1964 detection of the CMB at 2.725 K confirmed the cooling relation T = T₀(1+z) from which the habitable temperature window can be precisely calculated backward in time Cosmic Background Temperature Enters the Liquid Water Range
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