By considering the gravitational field as an optical medium with a radially-dependent index of refraction, we are able to show that a physical model of space being radially compressed by mass, rather than curved by mass, as in general relativity, yields the same results predicted by Einstein's theory of general relativity. We are further able to show that this spatial compression is equivalent to the Lorentz contraction of special relativity. The predictions of general relativity are all derived with relatively basic mathematics without reliance on the grossly complex Riemannian geometry needed for Einstein's curved space-time model.