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  • Robert Woodrow Wilson & CMB Radiation

    Reggie Jones
    American physicist & radio astronomer Robert Woodrow Wilson celebrates his 88th birthday this month [b. January 10, 1936]. He split a half-share of the 1978 Nobel prize in Physics with Arno Penzias [b. 1933], "for their discovery of cosmic microwave background radiation".
    The theoretical prediction that an expanding universe should be filled with thermal radiation is commonly credited to Ralph Alpher [1921-2007] & Robert Hermann [1914-1997], but the idea is certainly not original with them. In his 1934 book "Relativity, Thermodynamics and Cosmology", Richard Chace Tolman [1881-1948] analyzes expanding and contracting universes filled with thermal radiation. And the idea may well pre-date Tolman.
    In any case, by the late 1950s radio astronomers were beginning to look for this universal background radiation. In the mid 1960s a team led by Robert Dicke [1916-1997] was actively looking for the ubiquitous thermal radiation. But Dicke and his team were beaten to the finish line by Wilson & Penzias, who actually discovered it, despite the fact that they were not looking for it, and were evidently not even aware of the theoretical predictions.
    Wilson & Penzias were working together at Bell Laboratories, on a horn antenna that had been retired from communications research, preparing the antenna & detectors for a study of the 21 centimeter neutral hydrogen emission from the Milky Way.
    They began recording an excess antenna temperature in 1964, but were unable to explain it. In 1965 Penzias just happened to mention their problem in a conversation at M.I.T., which led to one person remembering a paper by Philip "P.J.E." Peebles [b. 1935], which led to Dicke, who realized that his group had been, as he put it, "scooped". After some consultation, Dicke's group and Penzias & Wilson published simultaneous letters describing the discovery in the July 1965 issue of the Astrophysical Journal (see links to the papers below).
    Today the cosmic microwave background (CMB), as this thermal radiation is now called, is certainly the critical target for observational cosmology. The CMB has been studied in detail by the COBE, WMAP, and Planck spacecraft, as well as a host of ground-based CMB observatories. It is the primary observational discriminator that led to the downfall of steady state cosmology, and the rise of big bang (expanding universe) cosmology. The CMB is fundamental to the modern standard model of cosmology.
    The photograph, dated circa 1978, comes from the Emilio Segrè Visual Archives of the American Institute of Physics. The caption reads: “Robert W. Wilson (left) and Arno Penzias (right) stand outdoors by Bell Laboratories horn radio antenna in Crawford Hill, New Jersey.”
    https://history.aip.org/phn/11504013.html (Biographical & professional profile - American Institute of Physics)
    https://www.pbs.org/wgbh/aso/databank/entries/dp65co.html (“Penzias and Wilson discover cosmic microwave radiation 1965” - PBS, People and Discoveries)
    https://www.lindahall.org/.../scien.../robert-woodrow-wilson (Linda Hall Library, Scientist of the Day, 10 January 2022)
    https://en.wikipedia.org/wiki/Cosmic_microwave_background (Cosmic microwave background - Wikipedia)
    https://ui.adsabs.harvard.edu/.../1965ApJ...142.../abstract (Dicke, Peebles, Roll & Wilkinson, 1965)
    http://bgandersson.net/ (B-G Andersson)
    https://en.wikipedia.org/wiki/Starmus_Festival (Starmus Festival Wikipedia)
    Posted originally by Tim Thompson, Senior NASA Astronomer (Retired)


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