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Who discovered the cosmic microwave background radiation in 1965?

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Oval map of the cosmic microwave background radiation from NASA's WMAP mission, showing a mottled pattern of blue, green, yellow, and red representing temperature variations. — Cosmic microwave background A full-sky map produced by the Wilkinson Microwave Anisotropy Probe (WMAP) showing cosmic background radiation, a very uniform glow of microwaves emitted by the infant universe more than 13 billion years ago. Color differences indicate tiny fluctuations in the intensity of the radiation, a result of tiny variations in the density of matter in the early universe. According to inflation theory, these irregularities were the “seeds” that became the galaxies. WMAP's data support the big bang and inflation models, and cosmic microwave background is at the farthest limits of the observable universe.

The cosmic microwave background (CMB) radiation was discovered in 1965 by American astrophysicists Arno Penzias and Robert Woodrow Wilson.12

While working at Bell Laboratories in Holmdel, New Jersey, the two scientists were using a horn antenna for radio astronomy when they detected a persistent, uniform radio noise coming from every direction in the sky. After ruling out all potential sources of interference—including equipment noise and even pigeon droppings—they consulted with Robert H. Dicke at Princeton University.132

Dicke and his colleagues, including James Peebles, had been theoretically predicting the existence of such background radiation as a remnant of the big bang. The two groups published their findings simultaneously in 1965, providing critical evidence for the big-bang theory and effectively ending the debate over the steady-state model of the universe. Penzias and Wilson were later awarded the 1978 Nobel Prize for Physics for this discovery.321