Inverse Square Law + Special Relativity

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Discussion Overview

The discussion revolves around the relationship between Newton's inverse square law, special relativity, and general relativity. Participants explore whether applying the principles of special relativity to Newton's law yields predictions similar to those of general relativity, as well as the implications for electromagnetic theory.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants propose that if Newton's inverse square law is modified to comply with special relativity, it may yield predictions similar to those of general relativity, though they acknowledge potential differences.
  • One participant asserts that the electromagnetic potential already accounts for retarded time effects, which are understood through Maxwell's equations and do not require general relativity.
  • Another participant notes that while results from applying special relativity to Newton's law are similar to general relativity, they do not account for spatial curvature and gravitational time dilation.
  • A participant references Wald's book on general relativity, suggesting that a different approach to gravity could have been more straightforward and that Einstein's discovery was pivotal in avoiding a flawed theory.
  • One participant questions whether Maxwell's equations can be reformulated in a manner analogous to general relativity.
  • A reference to "Electrodynamics in Curved Spacetime" from Misner, Thorne, and Wheeler's "Gravitation" is mentioned, indicating a potential resource for further exploration of these ideas.

Areas of Agreement / Disagreement

Participants express differing views on the implications of applying special relativity to Newton's law, with some suggesting similarities to general relativity while others highlight significant differences. The discussion remains unresolved regarding the extent of these similarities and the potential for reformulating Maxwell's equations.

Contextual Notes

There are limitations regarding the assumptions made about the applicability of special relativity to Newton's law and the definitions of terms like spatial curvature and gravitational time dilation, which remain unresolved in the discussion.

nassboy
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If one assumes that Newtons inverse square law does not act instantly at a distance, and instead obeys the rules of special relativity does it make similar predictions as general relativity?

Has anybody worked this out? Maybe the result is similar to maxwell's equations.
 
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The EM potential acting at a retarded time already followed from Maxwell's equations, well before relativity. The effect is well understood and has nothing to do with GR.
 
nassboy said:
If one assumes that Newtons inverse square law does not act instantly at a distance, and instead obeys the rules of special relativity does it make similar predictions as general relativity?

Has anybody worked this out? Maybe the result is similar to maxwell's equations.

Yes, and the results are similar to GR, but there are differences. Wald writes in his book on GR that this would have been the more straightforward way to describe gravity. Had Einstein not invented GR, we would very likely have been stuck with a flawed theory for a very long time (because if observations show a small discepancy, you can always model that by introducing extra terms).

Kaku has claimed that GR would only have been formulated in the 1970s, had Einstein not discovered it.
 
nassboy said:
f one assumes that Newtons inverse square law does not act instantly at a distance, and instead obeys the rules of special relativity does it make similar predictions as general relativity?
Similar but not the same. It doesn't predict spatial curvature and gravitational time dilation. Discussed here:
https://www.physicsforums.com/showthread.php?t=324457&p=2270590
 
Reversing the question then...can maxwell's equations be formulated more like GR?
 

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