Cosmological red shift and cosmic time dilation

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In summary, cosmological redshift refers to the phenomenon where light from distant galaxies is stretched to longer wavelengths as the universe expands, causing it to appear redder. This effect provides evidence for the expanding universe and helps determine distances to celestial objects. Cosmic time dilation, on the other hand, is the effect of time appearing to pass more slowly for objects moving away from an observer due to this expansion. Both concepts are integral to our understanding of the universe's dynamics and the implications of general relativity.
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andrew s 1905
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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 [11–13] 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
 
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Thanks, please close this thread. Regards Andrew
 

FAQ: Cosmological red shift and cosmic time dilation

What is cosmological redshift?

Cosmological redshift is the phenomenon where light from distant galaxies and other celestial objects is shifted to longer wavelengths (toward the red end of the spectrum) as it travels through the expanding universe. This redshift is a key piece of evidence for the Big Bang theory and the expansion of the universe.

How does cosmic time dilation relate to cosmological redshift?

Cosmic time dilation is the effect where time appears to pass more slowly for events occurring in distant parts of the universe compared to those nearby. This occurs due to the expansion of the universe. The same expansion that causes cosmological redshift also stretches the time intervals between events, making them seem longer when observed from Earth.

Why is cosmological redshift important in cosmology?

Cosmological redshift is crucial in cosmology because it provides evidence for the expanding universe and allows scientists to measure the rate of this expansion, known as the Hubble constant. It also helps in determining the distance to faraway galaxies and understanding the large-scale structure and evolution of the universe.

How do astronomers measure cosmological redshift?

Astronomers measure cosmological redshift by observing the spectral lines of light from distant galaxies. These lines, which correspond to specific elements, are shifted toward the red end of the spectrum. By comparing the observed wavelengths to the known rest wavelengths, astronomers can calculate the redshift and thus the relative velocity and distance of the galaxy.

What is the relationship between redshift and the age of the universe?

The relationship between redshift and the age of the universe is that higher redshifts correspond to earlier times in the universe's history. When we observe a galaxy with a high redshift, we are seeing it as it was when the universe was much younger. This allows scientists to study the evolution of galaxies and other cosmic structures over billions of years.

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