Hello, Do current theories of cosmological expansion take into account the effects expanding space would have on a beam of light travelling through space? i.e. if an expanding medium of gas with constant pressure decreases the temperature/velocity of particles, would an expanding medium of space decrease the velocity of light? (not sure what the analog of pressure is for spacetime...) given light's constant speed I assume this would actually redshift the wavelength akin to light exiting supermassive objects. If unaccounted for, this effect might mean observations of SN1A events overestimate distance as well as rate of expansion.