Is the CMBR a relic from the big bang or an image from background galaxies?

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Discussion Overview

The discussion centers on the nature of the Cosmic Microwave Background Radiation (CMBR) and whether it is a remnant from the Big Bang or light from distant galaxies. Participants explore historical perspectives, theoretical implications, and references related to the CMBR's origins.

Discussion Character

  • Debate/contested
  • Historical
  • Technical explanation

Main Points Raised

  • Some participants assert that the CMBR cannot be attributed to light from galaxies due to its spectrum and temperature variations.
  • One participant references a paper discussing how galaxies formed later can influence the light of the CMB.
  • Another participant mentions historical papers from the late 1960s and early 1970s that proposed the CMBR was a result of diffuse galaxies, which was later challenged.
  • It is noted that the absence of small fluctuations due to individual galaxies contradicts the idea that the CMBR originates from them.
  • Historical context is provided, indicating that the transition from steady state models to Big Bang explanations took time and was influenced by early observational data.

Areas of Agreement / Disagreement

Participants generally agree that the CMBR is not light from galaxies, but there are competing views regarding the historical context and implications of earlier models. The discussion remains unresolved regarding the influence of galaxies on the CMBR.

Contextual Notes

Participants reference specific papers and historical debates without reaching a consensus on the implications of those references. The discussion highlights the complexity of the topic and the evolution of ideas over time.

Lino
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Some time ago there was a thread which suggested that there was a logic / papers that demonstrated why the the CMBR could not be the result of ligh from background objects / galaxies. Unfortunately, I have not been able to locate the thread or associated material. Is this correct, and could anyone give me references to related material?

(I apprecialte that I am not / unlikely talking about light or resibual light from visible galaxies.)

Regards,

Noel.
 
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It is correct that the CMBR cannot be light from galaxies or similar objects. It could not explain its spectrum and the tiny angular variations of the temperature.
I do not know of any papers discussing this - it is just too far away from observations, I think.
 
Thanks MFB. I was reading a paper by Molnar & Birkinshaw on Contributions to the Power Spectrum of Cosmic Microwave Background from Fluctuations Caused by Clusters of Galaxies (ArXiv 0002271) and it reminded me of the thread - I probably just mis-remember!

Regards,

Noel.
 
The paper discusses how light of the CMB gets influenced by galaxies which formed later - they are in the path of the existing light and can influence it.
 
Thanks MFB.

Regards,

Noel.
 
mfb said:
I do not know of any papers discussing this - it is just too far away from observations, I think.

If you go back into the late-1960's and early-1970's you'd find plenty of papers. The idea that CMB was the result of diffuse galaxies was the "last stand" of the steady state model.

http://adsabs.harvard.edu/abs/1968Natur.217..339S

The problem with that explanation of the CMB was that you should see small fluctuations due to the individual galaxies, and you don't...

http://adsabs.harvard.edu/abs/1973ApJ...181..243B
http://adsabs.harvard.edu/abs/1973ApJ...182L..61C

One thing that happens a lot in astrophysics is that people come up with an idea, it gets killed, and then people forget why it got killed. Also looking at astrophysics history is interesting. The way it gets presented in textbooks, was that in 1965 when the CMB was discovered people immediately moved to support the big bang. In fact it took a few years, because the steady state people were able to come up with explanations for CMB, and the first set of measurements from sounding rockets actually went against the BB.

By the early 1970's, it was obvious that there were problems with the sounding rocket data, and that balloon and satellite data pretty clearly confirmed the big bang by showing that the spectrum was extremely smooth, and couldn't come from difuse galaxies.
 
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Thanks TwoFish. That makes sense.

Regards,

Noel.
 

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