According to my minimal understanding, a universe with the fate of the "Big Crunch" theory, has to come to a complete stop before it begins its journey in reverse. My understanding of slowing down, then stopping, is this. No matter how slow and delicate you proceed in doing so, at that moment when you actually stop, there is a measurable jerk, where the matter wants to keep going. On such a large scale (such as our universe), is it possible this might offset the universe greatly, and possibly upset everything in the universe, resulting in pure uncertainty of what will happen next? Think of the possibility of everything in the universe being pushed to one side, not knowing exactly where the partials end up could prevent us from knowing if indeed the universe would then collapse. Or maybe, the universe will decrease in speed, at such a gradual rate, that this above effect will be so minuet it will be almost undetectable. I have difficulty imagining the universe stopped, even for a small amount of time. And something must stop in order to change direction. Which logic is the case in this scenario? Or is there too much uncertainly to be exact?