The Speed of Light & Gravity: Varied Across the Universe?

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Discussion Overview

The discussion revolves around the concept of the speed of light and gravity, particularly whether these speeds vary across different regions of the universe. Participants explore implications of such variations on gravitational strength and the nature of universal constants.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • Some participants suggest that the speed of light may not be constant throughout the universe, raising questions about how this would affect the speed of gravity and its strength.
  • Others argue that gravity would remain the same regardless of the speed at which it travels, although the reasoning behind this assertion is questioned.
  • One participant notes that local measurements of light and gravity are constant, but that observations from a distance may show variations due to spacetime curvature.
  • Another participant points out that claims of changing light speed are often misrepresented in popular media, suggesting that variations are more accurately described in terms of changes in atomic properties rather than the speed of light itself.
  • It is mentioned that all massless particles, including photons and gravitons, are believed to travel at the fixed speed 'c'.

Areas of Agreement / Disagreement

Participants express differing views on whether the speed of light and gravity can vary across the universe, with some asserting that they remain constant while others propose that variations could exist. The discussion remains unresolved with multiple competing perspectives.

Contextual Notes

There are limitations in the discussion regarding the assumptions made about the constancy of universal constants and the implications of spacetime curvature on measurements. The relationship between observed variations and their interpretations is also not fully clarified.

lnsanity
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According to some physicist and cosmologist observation the speed of light is not a constant depending on region of the universe they observe and according to Einstein theory gravity move at the speed of light now my question is if gravity move at speed of light than gravity should move faster or slower in some region of the universe than would gravity be stronger or weaker if it travel faster or would it be the same ?
 
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It would be the same, although it should be noted work saying that universal constants like c vary throughout the universe are tenuous.
 


ok why it would be the same what is the mechanism of gravity that explain that it would remain the same ?
 


locally, the speed of light and gravity is constant...when viewed from a distance, measurement speeds can be different than c when gravity is present as spacetime curvature affects the observed measurements. Local measurements eliminates the observational affects of curvature.
 


Usually results that are reported about "the speed of light changing" are actually results about variations in the fine structure constant.

See for instance http://www.phys.unsw.edu.au/einsteinlight/jw/module6_constant.htm

This is reported in the popular press as "the speed of light changing over time", because news reporters seem to like that the lay audience will like that idea, and the editors think it makes a catchier title. The actual situation is rather less clear - physicists are more likely to interpret the resujlts in terms of atoms changing their properties than the speed of light varying.

Note that the two descriptions are experimentally indistinguishable, once the details of what you mean when you say "mesaure the speed of light" is worked out.

These effects are NOT predicted by relativity, and are not really confirmed either, so the best way to think about them (assuming they do actually exist) isn't especially clear.
 


I should have included: all massless particles are believed to travel at the fixed speed 'c'..of course that includes photons [light = electromagnetic radiation] and gravitons [gravity].
 

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