I asked recently on another thread about relativity and its affect on gravitation. I have been informed that gravity is due to how energy bends spacetime, not the Newtonian idea of mass or even the special "relativistic mass." However this leaves me wondering why general relativity does not involve velocity in its equations. According to E=(mc^2)/sqrt(1-v^2/c^2), relative velocity does have an impact on the total energy of an object. If so, why is it that an object traveling relative to Earth doesn't produce a larger gravitational attraction to Earth than an object of equal rest mass that is stationary?