Speed of light (from redshifted galaxies)

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Discussion Overview

The discussion revolves around the speed of light as measured from distant, redshifted galaxies, as well as the luminosity distance of celestial bodies moving away from Earth. Participants inquire about experimental evidence and data sources related to these topics, particularly focusing on type Ia supernovae.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants inquire about experiments or measurements of the speed of light from distant galaxies, questioning whether it remains constant at c.
  • There is a suggestion that experimental verification could address doubts regarding the constancy of the speed of light, with some theoretical physicists reportedly debating this issue.
  • One participant requests references for physicists who doubt that light in a vacuum travels at c.
  • Another participant proposes splitting the problem into two categories: the speed of light changing over time and changing over distance.
  • Concerns are raised about the measurement of luminosity distance for bodies moving away from us, with emphasis on the need to consider the effects of curved spacetime in such studies.
  • Participants share links to various arXiv papers that may provide relevant information on the topics discussed.

Areas of Agreement / Disagreement

Participants express differing views on the constancy of the speed of light and the implications of curved spacetime on measurements. There is no consensus on the validity of the claims regarding the speed of light or the methodologies for measuring luminosity distance.

Contextual Notes

Some participants note that questions about the speed of light over large distances cannot be adequately addressed without considering the effects of curved spacetime, indicating potential limitations in the current understanding and methodologies.

Myslius
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1) Are there any experiments/measurements of speed of light from distant (redshifted) galaxies?
2) Are there any experiments/measurements of luminosity distance of bodies moving away relative to us?
3) Where can I find type 1A supernova data (redshift and luminosity distance) for low z measurements, and high z.
So far i found few docs in arxiv: "NEW HUBBLE SPACE TELESCOPE DISCOVERIES OF TYPE Ia SUPERNOVAE AT z>=1:"
and "Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant"
About 50 type 1A supernovas. Is there more recent and complete list?
 
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Myslius said:
1) Are there any experiments/measurements of speed of light from distant (redshifted) galaxies?

Do you doubt that the speed of light from distant galaxies is c ?
 
Well, I'm not rejecting any possibility. Experimental verification would clear my doubts. Some theoretical physicists are arguing about that.
 
Myslius said:
Well, I'm not rejecting any possibility. Experimental verification would clear my doubts. Some theoretical physicists are arguing about that.

Can you provide a reference for any physicists who doubt that light in a vacuum travels at c ?
 
Myslius said:
http://arxiv.org/pdf/physics/0406104.pdf
http://arxiv.org/pdf/astro-ph/0101455v2.pdf
http://arxiv.org/pdf/0908.1539v1.pdf

I think we might split the problem into two: c changing over time, and c changing over distance.

Also, question 2) bothers me the most:
2) Are there any experiments/measurements of luminosity distance of bodies moving away relative to us?
Only one of the three authors of those papers is in a physics department ( U. of Hull, UK). I get the impression that none of them undertstand or have any regard for GR and are looking for explanations that are not needed or plausible.

Questions about the speed of light over large distances cannot be studied whilst ignoring effects of curved spacetime.
 

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