At the beginning of the universe

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SUMMARY

The discussion centers on the concept of varying speed of light (VSL) and its implications at the beginning of the universe. It concludes definitively that the speed of light is not faster now than it was in the early universe. The conversation emphasizes that all physical measurements are ultimately dimensionless ratios, as we cannot measure dimensionful quantities independently. For further reading, the discussion references several threads and a paper from arXiv.

PREREQUISITES
  • Understanding of varying speed of light (VSL) theories
  • Familiarity with dimensionless numbers in physics
  • Knowledge of physical measurement concepts
  • Basic grasp of cosmological principles
NEXT STEPS
  • Read about the implications of varying speed of light theories
  • Explore the concept of dimensionless quantities in physics
  • Investigate the foundational principles of cosmology
  • Review the referenced arXiv paper on the topic
USEFUL FOR

Physicists, cosmologists, and anyone interested in the fundamental principles of light speed and its implications in the early universe.

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at the beginning of the universe, is light's speed faster than nowadays?
 
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lwymarie said:
at the beginning of the universe, is light's speed faster than nowadays?

there are a few threads about the concpet of a varying speed of light (VSL), and to expand, the meaningfulness of any other varying dimensionful "constant".

https://www.physicsforums.com/showthread.php?t=58486
https://www.physicsforums.com/showthread.php?t=71643
https://www.physicsforums.com/showthread.php?t=71105

i might recommend reading this:
http://arxiv.org/PS_cache/hep-th/pdf/0208/0208093.pdf

bottom line: every physical measurement we make is ultimately measuring a dimensionless number or numbers. if we measure a dimensionful quantity (say, length), we measure it against another like dimensioned quantity (say, a ruler) called a standard or a unit. we count tick marks. we mortals cannot measure a dimensionful quantity in and of itself and cannot measure a change in such a quantity in and of itself. we can only measure such a change against some other like dimensioned quantity, and the only salient measure is that ratio (of say, the speed of light against some other measure of speed), not either of the quantities being compared.

r b-j
 
Last edited by a moderator:
lwymarie said:
at the beginning of the universe, is light's speed faster than nowadays?

The short answer is "no".

The middle length answer is another question - "how could you tell?"
 

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