Vacuum permittivity as a fundemental dimensioned unit

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Discussion Overview

The discussion revolves around the nature of vacuum permittivity (ε₀) and its relationship to fundamental constants such as the gravitational constant (G), Planck's constant (h), and the speed of light (c). Participants explore whether ε₀ can be expressed in terms of these constants and the implications for permeability.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant suggests that everything can be expressed in units of G, h, and c, but questions the independence of ε₀ from these constants.
  • Another participant asserts that ε₀ is directly related to c.
  • A subsequent reply confirms the relationship between ε₀ and c, noting that a combination of c and ε₀ yields permeability.
  • One participant considers rephrasing their question to inquire if permeability and/or permittivity could be expressed in terms of G, h, and c, indicating that the question is equivalent to asking about permeability.
  • Another participant points out that the value of μ₀ in SI units is not a measured constant but is defined arbitrarily as 4π × 10^-7.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between ε₀, permeability, and the fundamental constants G, h, and c. The discussion remains unresolved regarding the independence of ε₀ from these constants.

Contextual Notes

Participants acknowledge the dependence of certain constants on definitions and the implications of these definitions on the relationships being discussed. There are unresolved aspects regarding the mathematical relationships between these constants.

Phrak
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As the usual argument goes, as I understand it, everything can be expressed in units of G, h and c. (though this argument exclude the particle masses from consideration.)

The permittivity of the vacuum seems to be independent of G,h,c. Am I wrong?
 
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epsilonzero is directly related to c.
 
clem said:
epsilonzero is directly related to c.

Yes, thank you. One combination of c and epsilon yields permeability.

I was thinking of rephrasing, to ask if permeability and/or permittivity could be expressed in c,G,h, but the question is equivalent since mu nu c^2 = 1. The question is equal to asking about permeability.
 
Last edited:
muzero in SI is not a measured constant. It is arbitrarily defined as 4piX10^-7.
 

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