This paper postulates all massive objects from electrons to galaxies can be modeled as massless superstrings and the force of gravity is a vector component of string tension. Where, gravity, which is an emergent property of general relativity, is caused by tension in massless supersymmetric strings called gravitons. In addition, this paper attempts to unify Einstein's theory of general relativity and quantum mechanics or the wave nature of matter for a theory of quantum gravity. This paper also assumes all massive objects can be modeled as heterotic or closed strings and the force of gravity is a fundamental property of string theory. In this paper the relationship between string theory and general relativity are simplified by allowing the equations for general relativity to approach the Newtonian limit for small velocity. Background: The first particle string models were called bosonic strings because only bosons or force carriers like photons; gluons and the Higgs particles were modeled. Later, superstring theory was developed that predicted a connection or "super-symmetry" between bosons and fermions where fermions are elementary particles like electrons, protons and quarks that compose all ordinary matter.