When you read the Einstein digital papers, you understand how gravity works. Einstein said things like “the curvature of light rays occurs only in spaces where the speed of light is spatially variable”. Note that he never abandoned this, and he never said light curves because it follows the curvature of spacetime. Instead he said a gravitational field is a place where space is “neither homogeneous nor isotropic”, he referred to Huygen’s principle, and he talked about “the refraction of light rays by the gravitational field”. So did Newton, see…