Cosmic microwave background radiation

In cosmology, the cosmic microwave background radiation (CMB) is a form of electromagnetic radiation discovered in 1964 that radiates throughout the universe in the microwave range.

Detection, prediction and discovery

Main article: Discovery of cosmic microwave background radiation

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The CMB was predicted by George Gamow, Ralph Alpher, and Robert Hermann in the 1940s and was accidentally discovered in 1964 by Arno Penzias and Robert Woodrow Wilson, who received a Nobel Prize in Physics in 1978 for this discovery. The interpretation of the CMB was a very controversial issue in the 1960s with some proponents of the

Related Topics:
George Gamow - Ralph Alpher - Robert Hermann - 1940s - 1964 - Arno Penzias - Robert Woodrow Wilson - Nobel Prize in Physics

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steady state theory arguing that the CMB was the result of scattered starlight from distant

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galaxies. Using this model, and based on the study of narrow absorption line features in the spectra of stars, the astronomer Andrew McKellar wrote in 1941: "It can be calculated that the 'rotational' temperature of interstellar space is 2 K." However, during the 1970s the consensus view moved to the point of view that the CBR was the remnant of the big bang. Among the observations that swung the astronomical community toward this point of view were the fact that the CBR was much smoother than would be expected from scattered star light.

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Because water absorbs microwave radiation, a fact that is used to build microwave ovens, it is rather difficult to observe the CMB with ground-based instruments. CMB research therefore makes increasing use of air and space-borne experiments. Ground-based observations of the CMB are usually made from high altitude locations such as the Chilean Andes and the South Pole.

Related Topics:
Microwave oven - Chilean Andes - South Pole

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