What If the Speed of Light Were No Longer Constant?

[juju]

Hi Antonio,

Yes, permittivity and permeability are two properties which affect the speed of light.

I would propose that there are other properties which MAY affect it also.

What about effects from such phenomena as spatial curvature, virtual particle flux, quantum vacuum fluctuations, etc.

juju

 

[Antonio Lao]

What about effects from such phenomena as spatial curvature, virtual particle flux, quantum vacuum fluctuations, etc.

Virtual photons created from quantum vacuum fluctuations don't stay around long enough for their speeds to be measured.
I'm not sure space curvature slows the speed of light. I'm checking on this. But there is such a thing as gravitational redshift, the decrease of photon's energy by gravity field.