Gravitation as Vacuum Polarizability: Revision with Modern Cosmological Data

In this study, gravitation is formulated in terms of the vacuum polariz-ability and a variable dielectric constant (ϵ). Treated as a scalar field,gravitation is unified with electromagnetic interactions and derived froma Lorentz-invariant Lagrangian principle. R. H. Dicke’s original 1957 ap-proach [1] is revised with modern cosmological data [2] and current obser-vational constraints. By incorporating vacuum energy density and volu-metric matter scaling (ϵ−3/2) into the model’s cosmological equations, theage of the universe is calculated to be 13.85 billion years, achieving fullconsistency with the Standard Model (ΛCDM). On a local scale, PPN pa-rameters (γ = 1, β = 1), Mercury’s perihelion precession, the Nordtvedteffect (η = 0), and the propagation speed of gravitational waves (cg = c)are found to be consistent with Cassini and LIGO/Virgo (GW170817) data.Furthermore, the time dilation analysis at high redshifts provides a naturalexplanation for the early galaxy formations observed by the James WebbSpace Telescope (JWST).