I was working on a thought experiment to help myself understand the curvature of space when I got stuck on something (I hope) is simple. I realize this might be a basic problem but I was hoping to generate some discussion. The experiment involves a "universe" two neutrally charged masses of equal weight. In this universe, the only force acting on either mass is the gravitational attraction and at the beginning of the experiment the objects are at rest relative to each other. Using Newtons law of Gravity, I expect acceleration to be increasing towards infinity as separation decreases towards zero given that the force of attraction is inversely proportional to the square of separation. On the other hand using special relativity I expect acceleration to approach zero as the (negative) rate of change in separaration approaches the speed of light. I wanted to explore this further but I am having trouble deriving a non relativistic function for Gravitational Jerk (da/dt) because although I can express time from rest in terns of distance I can't quite figure out distance from rest in terms of time. Is anyone aware of accessible work on classical Gravitional Jerk???