What If the Speed of Light Varied: Implications for Our Universe?

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Discussion Overview

The discussion revolves around the hypothetical implications of a varying speed of light (c) in the universe. Participants explore the theoretical consequences of such a variation on fundamental physics, including its effects on causality, atomic stability, and our understanding of the universe. The conversation touches on both conceptual and speculative aspects of this idea.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • Some participants speculate on the effects of a varying speed of light, suggesting that early variations might not have observable consequences, depending on their magnitude.
  • One participant proposes that if c were currently varying, it could lead to unpredictable changes in space and time, increasing uncertainty in physical interactions.
  • Concerns are raised about the stability of atomic structures if the speed of light were to change, particularly regarding electromagnetic interactions and energy conservation.
  • Another participant questions how one would measure or perceive a variation in a dimensionful constant like c, emphasizing the importance of dimensionless quantities in physical measurements.
  • There is a discussion about the implications for special relativity if c were different for different observers, suggesting that this would undermine the model's validity.
  • Some participants reference specific literature related to the time-variation of fundamental constants, indicating a desire for deeper exploration of the topic.
  • Questions are posed regarding the nature of measurement and perception of physical quantities, particularly in relation to changing units and standards.

Areas of Agreement / Disagreement

Participants express a range of views on the implications of a varying speed of light, with no consensus reached. Some agree on the potential consequences for physical laws, while others challenge the feasibility of measuring such variations and the implications for established theories.

Contextual Notes

Limitations include the speculative nature of the discussion, with many assumptions about the consequences of a varying speed of light remaining unresolved. The conversation also highlights the dependence on definitions and measurement standards in discussing physical constants.

Who May Find This Useful

This discussion may be of interest to those exploring theoretical physics, particularly in the context of fundamental constants and their implications for our understanding of the universe.

spidey
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So light has constant velocity..what if C varies as per galilean relativity..
What will happen?
Can't we explain something(experiments or observations) if that happens?
Will there be any change in our normal life? since we use light to see...
Can't we come to E=mc2?
Any change in our view of universe?
 
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I'll speculate on some items...maybe a theoretically correct answer will be posted...

If the speed of light were different early in the universe from present we might not see many effects, depending on the magnitude of the difference. I believe some suspect it might have varied in the distant past. There may be evidence the fine structure contant has varied ever so slightly.

If "c" were currently varying to any observable degree, casuality would also vary...space and time might become unpredictable... we'd be even harder pressed to tell before and after if we did not know how fast the information was transmitted...uncertainty would seem to increase dramatically...much if not all would be more unpredictable...

I think other constants would also vary ruining atomic stability...think about electrons interactions with nuclei...via electromagnetic fields...if the speed changed, the field would change and EMF forces would vary...I guess metals, for example, might become slightly unstable...weaker then stronger...rest energy mc^2 would also vary screwing up energy conservation in interactions...likely the universe would not exist if it were an observable magnitude...electricity might surge thru transmission lines...
 
i would suggest that you ask yourself exactly what the meaning of a variation of a dimensionful constant would be. how would we measure such a variation? or even perceive it? ultimately, we measure only dimensionless quantities usually as the ratio of a dimensionful quantity relative to some standard or unit of the same dimension.

check out Carlip: "Have physical constants changed with time?"

and

Duff: "Comment on time-variation of fundamental constants", hep-th/0208093 (2004)

Duff, Okun, and Veneziano: "Trialogue on the number of fundamental constants", JHEP 203 23 (2002), physics/0110060
 
"for all observers, c is constant"..so what if c is different for different observers..it didnt mean the value of c changes from past to future Or about dimensionless constants...i know for c,if we change the units, we will get different value..sorry for not being elaborative...
 
If c is different for different observers, then special relativity would not be a good model of our world. I've heard that two instances where special relativity can be seen in "everyday" life are magnetic fields due to Lorentz contraction of charges moving in a wire, and the colour of gold.
 
atyy said:
...magnetic fields due to Lorentz contraction of charges moving in a wire...
Care to expand?
 
spidey said:
"for all observers, c is constant"..so what if c is different for different observers..it didnt mean the value of c changes from past to future Or about dimensionless constants...i know for c,if we change the units, we will get different value..sorry for not being elaborative...

spidey, please ask yourself "how does one get a different value?" be very specific and careful about the answer. consider how we measure or perceive the quantitative value of any physical quantity. consider units, references, standards, and the definitions of such.
 

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