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Cosmic microwave background spectral distortions – Fluctuations in the energy spectrum of the microwave background Cosmological perturbation theory – theory by which the evolution of structure is understood in the big bang model Pages displaying wikidata descriptions as a fallback
The discovery of cosmic microwave background radiation constitutes a major development in modern physical cosmology.In 1964, US 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.
Cosmic background radiation is electromagnetic radiation that fills all space. The origin of this radiation depends on the region of the spectrum that is observed. One component is the cosmic microwave background .
The cosmic microwave background (CMB) provides a snapshot of a largely isotropic and homogeneous universe. The largest scale feature of the CMB is the dipole anisotropy; it is typically subtracted from maps due to its large amplitude.
Differences in the temperature of the cosmic background are smoothed by cosmic inflation, but they still exist. The theory predicts a spectrum for the anisotropies in the microwave background which is mostly consistent with observations from WMAP and COBE. [6] However, gravity alone may be sufficient to explain this homogeneity. [7]
The time frame for recombination can be estimated from the time dependence of the temperature of the cosmic microwave background (CMB). [4] The microwave background is a blackbody spectrum representing the photons present at recombination, shifted in energy by the expansion of the universe.
Already in 1967, Dennis Sciama predicted that the cosmic microwave background has a significant dipole anisotropy. [41] [42] In recent years, the CMB dipole has been tested, and the results suggest our motion with respect to distant radio galaxies [43] and quasars [44] differs from our motion with respect to the cosmic microwave background.
RELIKT-1, a Soviet cosmic microwave background anisotropy experiment on board the Prognoz 9 satellite (launched 1 July 1983), gave the first upper limits on the large-scale anisotropy. [33]: 8.5.3.2 The other key event in the 1980s was the proposal by Alan Guth for cosmic inflation. This theory of rapid spatial expansion gave an explanation for ...