History of CMB, prediction of 1 in 100,000?

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SUMMARY

The cosmic microwave background (CMB) temperature variations were first measured by the Cosmic Background Explorer (COBE) satellite, revealing fluctuations of 1 part in 100,000. Robert Dicke, a key figure in this discovery, predicted the existence of the CMB while developing radar receivers in the 1940s and 1960s. His group at Princeton confirmed the detection of CMB radiation using a Dicke radiometer, following the accidental discovery by Arno Penzias and Robert Wilson at Bell Labs. The theoretical groundwork laid by Dicke and others transitioned early universe theories from speculation to established physics, with significant contributions from Steven Weinberg and George Gamow.

PREREQUISITES
  • Understanding of cosmic microwave background (CMB) physics
  • Familiarity with Brans-Dicke theory
  • Knowledge of Dicke radiometer technology
  • Awareness of key figures in cosmology, including Robert Dicke and Steven Weinberg
NEXT STEPS
  • Research the Cosmic Background Explorer (COBE) satellite findings and methodologies
  • Study Robert Dicke's contributions to cosmology and radar technology
  • Examine the implications of Brans-Dicke theory on early universe models
  • Review Steven Weinberg's publications on cosmic microwave background anisotropies
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Astronomers, cosmologists, and physics students interested in the historical development and theoretical foundations of cosmic microwave background research.

windy miller
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Variations in the tamperatureo of the CMB are 1 part in 100,00. My understanding is that this was first measured by COBE, But was this value predicted?
What were the ranges of estimates for its value before it was measured?
 
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Robert Dicke predicted the CMB while developing radar receivers beginning in the 1940s into 1960s. Dicke strongly encouraged the working group at Bell Labs who first detected the CMB radiation on the Homdel horn antenna. Dicke's Princeton research group verified the discovery and documented the second CMB detection using a super-cooled receiver of his design.

In the early 1960s, work on Brans–Dicke theory led Dicke to think about the early Universe, and with Jim Peebles he re-derived the prediction of a cosmic microwave background (having allegedly forgotten the earlier prediction of George Gamow and co-workers). Dicke, with David Todd Wilkinson and Peter G. Roll, immediately began building a Dicke radiometer to search for the radiation.

They were preceded by the accidental detection made by Arno Penzias and Robert Woodrow Wilson (also using a Dicke radiometer), who were working at Bell Labs near Princeton.[11][12] Nevertheless, Dicke's group made the second clean detection, and their theoretical interpretation of Penzias and Wilson's results showed that theories of the early universe had moved from pure speculation into well-tested physics.[13][14]

I read a paper by Steven Weinberg (IMS) describing expected thermal variations in CMBr based on Brans-Dicke theory confirmed by COBE measurements. I would like to say Weinberg predicted 10-5 anisotropies but need to locate the relevant texts and publication dates. George Gamov likely maintains precedence, as the above excerpt describes.
 
Last edited:
Let me know if you find it thanks.
 
windy miller said:
Let me know if you find it thanks.
No, I did find revisions to his cosmology primer "First Three Minutes" that include CMBr (rev 3) and significance of anisotropies (rev 6 ), not a peer reviewed pub but in the OP period of interest.

Weinberg published numerous cosmology papers on the topic but not specifically "predictive".
From early this century:
astro-ph gr-qc hep-th
A No-Truncation Approach to Cosmic Microwave Background Anisotropies​
Authors: Steven Weinberg
Abstract: We offer a method of calculating the source term in the line-of-sight integral for cosmic microwave background anisotropies without using a truncated partial-wave expansion in the Boltzmann hierarchy.​
 

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