Discovery of cosmic microwave background radiation

Aspect of the history of modern physical cosmology

The discovery of cosmic microwave background radiation constitutes a major development in modern physical cosmology. In 1964, American physicist Arno Allan Penzias and radio-astronomer Robert Woodrow Wilson discovered the cosmic microwave background (CMB), estimating its temperature as 3.5 K, as they experimented with the Holmdel Horn Antenna. The new measurements were accepted as important evidence for a hot early Universe (Big Bang theory) and as evidence against the rival steady state theory as theoretical work around 1950 showed the need for a CMB for consistency with the simplest relativistic universe models.

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