Quantum theory and mechanics accept that "time" is constant, but refuse to accept that once in permanency-always in permanency. In other words, 12 inches will always equal a foot. Period. 1+1 will always equal 2. Forever. Not to break your quantum leaping hearts, but the element of time cannot cancel itself out. It is simple grade school math. 1+1=2-1=1; not ZERO. But that small irrefutable, but important factoid is only for my science geeks. Let's move on.
Time cannot undo itself or turn in on itself. Time can however, be overlapped with another time line. In other words, while this thing is happening one place at this moment in time, this other event is also taking place at the same time somewhere else. Time was the same; only the actions were different.
So you see, in our own little way, we are all time travelers. By being in existence, in action, constant motion, constant movement-or lack thereof, we are utilizing one of the most powerful tools we have. Time. Our daily vocabulary is riddled with it. "Take your time...time to go...what time will you be here...stop wasting time..." and the list goes on and on. Time is not a verb, it's a noun. Just remember, it is still the one of the many natural elements of existence that we cannot synthetically reproduce no matter how far we turn our clocks back so please make the most of your "time" and utilize it wisely-because once it's gone-it's gone.