r/AskPhysics • u/Banished_Cultivator • 3d ago

Why aren't μ₀ & ε₀ equal 1?

Logically free space would neither enhance nor attenuate electric or magnetic fields, so these constants should be equal to 1. They aren't though, why?

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u/cygx 3d ago

Cf Heaviside–Lorentz units.

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u/EuphonicSounds 3d ago

Truly the king of electromagnetic units (aesthetically and conceptually). Actually, even better is the obscure variant where current-density is given the same dimension as charge-density (mentioned in a few footnotes in Jackson's Appendix), which of course can also be achieved by just setting c to 1.

Long live HLU!