Cosmological red shift and cosmic time dilation

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Discussion Overview

The discussion centers around the claims made in a paper regarding cosmological redshift and cosmic time dilation, particularly focusing on the validity of the author's interpretations of the FLRW metric and its implications in general relativity (GR). Participants express varying levels of expertise and seek to evaluate the correctness of the claims presented in the paper.

Discussion Character

  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant questions the author's understanding of general relativity, specifically regarding the invariability of the time coordinate in the FLRW metric.
  • Another participant asserts that the claim of physical differences between conformal coordinates and standard FLRW coordinates is incorrect, emphasizing that such transformations do not alter physical observables.
  • A claim is made that the paper incorrectly states the standard derivation of the relationship between cosmological redshift and the expansion of the scale factor is wrong.
  • A previous thread discussing the same paper is referenced, indicating ongoing interest and debate about its claims.

Areas of Agreement / Disagreement

Participants express disagreement regarding the claims made in the paper, with multiple competing views on the validity of the author's interpretations and assertions. No consensus is reached on the correctness of the claims.

Contextual Notes

Participants note potential issues with the author's understanding of general relativity and the implications of coordinate transformations, but do not resolve these concerns or clarify the assumptions underlying the claims.

andrew s 1905
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TL;DR
This paper claims the normal explanation of red shift is wrong and is in fact due to cosmic time dilation. I would like an expert view on its merit.
This https://www.frontiersin.org/articles/10.3389/fphy.2022.826188/full#h14 paper makes the claim as in the summary.

I don't have the experience to judge the merit of the claim. I would value any views on it is correct or not and if incorrect where the error(s) is (are).

I do have some understanding of the various coordinate system mentioned but the claim seem to be one of physical differences not just coordinate transform.

Thanks in advance Andrew
 
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This quotation shows that the author's knowledge of GR is shaky. Re the FLRW metric.

"In contrast to the space coordinates, the time coordinate is assumed to be invariable during the Universe history. This is somewhat strange and surprising, because other solutions in GR such as the well-known Schwarzschild solution [1113] involve distortions in space and time together."

This is poor.
 
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I see at least two obvious falsehoods in the paper:

(1) It claims that the FLRW metric in conformal coordinates is physically different from the FLRW metric in standard FLRW coordinates. This is false: conformal coordinates are a useful tool (see, for example, their usage in Davis & Lineweaver 2003 to clarify the meaning of various cosmological parameters), but transforming to conformal coordinates does not change anything about physical observables.

(2) It claims that the standard derivation of the relationship between cosmological redshift and the expansion of the scale factor, found in many textbooks and papers, is wrong.
 
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Thanks sorry I missed it. Andrew
 
Thanks, please close this thread. Regards Andrew
 

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