Gravity at large scales: force hierarchy or charge cancellation?

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SUMMARY

Gravity is significantly weaker than electromagnetism at the particle level, with a strength ratio of approximately 10⁻³⁶. Despite this, gravity dominates interactions at cosmological scales due to the electrical neutrality of matter, which causes electromagnetic fields to cancel out over large distances. Gravity, lacking negative charges, accumulates without cancellation, leading to its large-scale dominance. The hierarchy problem, however, specifically concerns the disparity in coupling constants and mass scales in fundamental physics, not the dominance of gravity at cosmological distances. This distinction clarifies that gravitational dominance at large scales arises from charge distribution rather than fundamental coupling strengths.

PREREQUISITES

  • Fundamental interactions: gravitational and electromagnetic forces
  • Concept of coupling constants and running constants in quantum field theory
  • Charge neutrality and field cancellation in electromagnetism
  • Hierarchy problem in particle physics and its relation to mass scales

NEXT STEPS

  • Study the hierarchy problem in the Standard Model and beyond
  • Explore the role of charge neutrality in large-scale electromagnetic field behavior
  • Investigate the mathematical formulation of coupling constants and running constants in quantum field theory
  • Examine cosmological models that incorporate gravitational dominance and electromagnetic cancellation

USEFUL FOR

Physicists, cosmologists, and students interested in fundamental forces, the hierarchy problem, and the large-scale behavior of gravity and electromagnetism will benefit from this discussion. It is particularly relevant for those studying particle physics, quantum field theory, and cosmology.

Roberto Pavani
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TL;DR
Gravity dominates at cosmological scales even though it is not stronger than electromagnetis, simply because matter is electrically neutral on average?
We know that gravity is much weaker than electromagnetism at the particle level (~10⁻³⁶ ratio).
Yet gravity is the dominant interaction at cosmological scales.
It seems to me that the explanation (my naive one) is straightforward: matter is electrically neutral on average, so EM fields from different sources cancel at large distances. Gravity, having no negative "charge," accumulates without cancellation.
If this is correct, then the so-called "hierarchy problem" between gravity and EM is not really about the coupling constants themselves, but about the statistical distribution of charges in the universe.
Is this view standard/accepted/discussed, or am I oversimplifying something?
 
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You correctly explained why gravity is dominant at cosmological scales, but the hierarchy problem is not about the cosmological scales. It's about values of various constants (or running constants) in the action, like masses and coupling constants.
 
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Demystifier said:
the hierarchy problem is not about the cosmological scales.
You're right, I misused the term 'hierarchy problem', that's about the coupling constants in the action, not about cosmological dominance.
Thanks for the clarification. My point was limited to the observational fact: gravity dominates at large scales simply because of charge neutrality, not because of the relative strength of the constants.
 
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