As we have stated, time is but a factor in our equations, which allow us to travel back in time, when permission is granted on rare occasions and for good cause, and travel forward on even rarer occasions. The motion and placement of objects, sub-atomic or otherwise, are predictable, given their placement and motion and composition at any given point.
Time travel involves reversing or accelerating activity that is predictable.
This reversing or accelerating involves forcing the issue, as under normal circumstances objects proceed based on their surroundings, your familiar world. The forward press or falling backward is due to direction of flow, of what is just another element in your Universe. You are unaware of this element, as the steady forward progression is something you consider a given. Nothing is by chance, and no motion is without reason or cause. To you, in your perception, time is steady in its progression, but when the press of this ingredient is stopped, or diminished, what had occurred telescopes back in activity that is the reverse of what just occurred.