Grand Relativity: Coupled Variation of G and c in Cosmology

This paper presents Grand Relativity (GRL), a unified cosmological framework in which the speed of light (c) and the gravitational constant (G) vary coherently across spacetime while preserving the reciprocal relationship G ∝ 1/c². Spatial variations in c and G provide geometric explanations for several major cosmological phenomena. Flat galactic rotation curves arise from radial gradients in the galactic causal field, while the universe’s apparent acceleration reflects a large-scale structure in which outer regions possess higher c and weaker curvature. A primordial high-c, low-G epoch naturallyreproduces the conditions associated with inflation without invoking an inflation field, and diminishing c near strong curvature prevents singular collapse. The CMB Cold Spot emerges as a low-c, high-G causal basin, while the Axisof Evil traces the large-scale orientation of the causal gradient ∇c. These features form a unified causal axis whose late-time signatures appear as hemispherical luminosity dipoles in Type Ia supernovae and quasars, as well as directional variations in the Hubble expansion rate. Large-scale structural alignments, including quasar polarization coherence and galaxy spin dipoles, further support the presence of a global causal gradient. GRL thus offers a single geometric mechanism linking early and late-time anisotropies, providing a coherent alternative to ΛCDM in which cosmic acceleration, structure formation, and apparent isotropy arise naturally from variations in the causal field.