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Cosmic background radiation

Electromagnetic radiation from the Big Bang

Cosmic background radiation
Summary

Electromagnetic radiation from the Big Bang

COBE]] data: uncorrected (top); corrected for the dipole term due to our [[peculiar velocity]] (middle); corrected additionally for contributions from our galaxy (bottom).

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. This component is redshifted photons that have freely streamed from an epoch when the Universe became transparent for the first time to radiation. Its discovery and detailed observations of its properties are considered one of the major confirmations of the Big Bang. Background radiation is largely homogeneous and isotropic. A slight detectable anisotropy is present which correlates to galaxy filaments and voids. The discovery (by chance in 1965) of the cosmic background radiation suggests that the early universe was dominated by a radiation field, a field of extremely high temperature and pressure.

There is background radiation observed across all wavelength regimes, peaking in microwave range (cosmic microwave background), but also notable in infrared range (cosmic infrared background) and X-ray range (X-ray background). Fluctuations in cosmic background radiation across regimes create parameters for the amount of baryonic matter in the universe. See also cosmic neutrino background and extragalactic background light.

The Sunyaev–Zel'dovich effect shows the phenomena of radiant cosmic background radiation interacting with "electron" clouds distorting the spectrum of the radiation.

Timeline of significant events

1896: Charles Édouard Guillaume estimates the "radiation of the stars" to be 5.6 K.

1926: Sir Arthur Eddington estimates the non-thermal radiation of starlight in the galaxy has an effective temperature of 3.2 K. http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1927Sci....66...81E&db_key=AST&data_type=HTML&format=&high=42ca922c9c22437

1930s: Erich Regener calculates that the non-thermal spectrum of cosmic rays in the galaxy has an effective temperature of 2.8 K.

1931: The term microwave first appears in print: "When trials with wavelengths as low as 18 cm were made known, there was undisguised surprise that the problem of the micro-wave had been solved so soon." Telegraph & Telephone Journal XVII. 179/1"

1938: Walther Nernst re-estimates the cosmic ray temperature as 0.75 K.

1946: The term "microwave" is first used in print in an astronomical context in an article "Microwave Radiation from the Sun and Moon" by Robert Dicke and Robert Beringer.

1946: Robert Dicke predicts a microwave background radiation temperature of 20 K.

1946: Robert Dicke predicts a microwave background radiation temperature of "less than 20 K" but later revised to 45 K.

1946: George Gamow estimates a temperature of 50 K.

1948: Ralph Alpher and Robert Herman re-estimate Gamow's estimate at 5 K.

1949: Ralph Alpher and Robert Herman re-re-estimate Gamow's estimate at 28 K.

1960s: Robert Dicke re-estimates a MBR (microwave background radiation) temperature of 40 K.

1965: Arno Penzias and Robert Woodrow Wilson measure the temperature to be approximately 3 K. Robert Dicke, P. J. E. Peebles, P. G. Roll and D. T. Wilkinson interpret this radiation as a signature of the Big Bang.

References

References

  1. Scott, Douglas. (2005-10-26). "The standard cosmological model". Canadian Journal of Physics.
  2. (2024-09-01). "The cosmic microwave background lensing imprint of cosmic voids detected in the WISE-Pan-STARRS luminous red galaxy catalog". Astronomy & Astrophysics.
  3. (September 2002). "Cosmic Microwave Background Anisotropies". Annual Review of Astronomy and Astrophysics.
  4. (12 March 2014). "First minutes of the Big Bang". What is USA News.
  5. (2018-06-19). "Looking at cosmic near-infrared background radiation anisotropies". Reviews of Modern Physics.
  6. Birkinshaw, Mark. (1999-03-01). "The Sunyaev–Zel'dovich effect". Physics Reports.
  7. (3 July 1995). "History of the 2.7 K Temperature Prior to Penzias and Wilson". Apeiron.
Wikipedia Source

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