In 1964 and 1965, Arno Penzias and Robert Wilson, radio astronomers at Bell Labs in Holmdel, New Jersey, used a sensitive horn antenna built for satellite communication research to measure a faint, uniform microwave signal arriving from every direction in the sky, a signal they could not explain away as instrument noise or local interference, even after ruling out droppings left by pigeons nesting inside the antenna. Consulting with a nearby Princeton group led by Robert Dicke, who were independently building equipment to search for exactly this kind of relic radiation, predicted decades earlier as the afterglow of an early hot, dense universe, the two teams recognized what Penzias and Wilson had already found: the cosmic microwave background, direct observational evidence for the big bang theory. The discovery was effectively fatal to the big bang's chief rival, the steady state theory, which predicted no such uniform relic radiation at all. Penzias and Wilson shared the 1978 Nobel Prize in Physics for the discovery.
Facts
MethodSourced to the subject's own accountPenzias and Wilson used a supersensitive 6-meter horn antenna, originally built to detect radio waves bounced off Echo balloon satellites, cooled with liquid helium to minimize thermal noise, and measured a faint uniform microwave signal arriving from every direction of the sky. 2 Key FindingSourced to the subject's own accountThe signal was about 100 times more intense than expected, spread evenly over the sky, and present day and night; measured at a wavelength of 7.35 centimeters, corresponding to a background temperature near 3.5 K, providing direct evidence for the big bang and against the steady state theory. 2 LocationSourced to the subject's own accountBell Telephone Laboratories, Crawford Hill, Holmdel, New Jersey. 2 Connections
Conducted By
Source Arno Penzias (Britannica)
Source Robert Wilson (Britannica)
Operated By
Source Arno Penzias (Britannica)
Tests
Source Arno Penzias (Britannica)
Uses
Sources
1. Arno Penzias (Britannica)
Encyclopaedia Britannica
2. Discovery of Cosmic Microwave Background Radiation (Wikipedia)
WikipediaHistory sectionQuote, History section
Bell Telephone Laboratories, Crawford Hill, Holmdel, New Jersey
Cosmic microwave background (Wikipedia)
In Group: Physics Experiments, Article textQuote, In Group: Physics Experiments, Article text
The accidental discovery of the CMB in 1964 by the American radio astronomers Arno Allan Penzias and Robert Woodrow Wilson was the culmination of work initiated in the 1940s.
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