A Model for Massless Gravity: The Maths that makes Interstellar Drives possible.

This paper presents a model for massless gravity. Stretching of space time via electromagnetic forces acting at discontinuities replaces gravitaitonal mass. A captured half photon model provides a natural mechanism for sampling the Ricci tensor. Charge is an artifact of repeaded temporal reflection of a captured half photon and corresponds to raised potential at the discontinuity. Einsteins field equations are derived from stress in spacetime. Removal of the need of a mass quanta points towards continuous creation as the right model for the origin of matter in the universe. It also makes 'reaction massless star drives' achievable.