Here is a bit that I wrote years ago.
So they say that time machines will never be invented. Well, that may be true to an extent. It may very well be true that it is impossible to jump back and forth through our universe, but what about virtual realities?
For time travel to be possible, we would first need to invent the creation of a virtual reality and in order for there to be a virtual reality, we would first need a computer capable of processing massive amounts of information at near instant speeds. Some may say that the odds of this happening are slim to none, but with exponentially increasing advances in technology and processing power described by Gordon E. Moore or “Moore’s Law” stating that “the number of transistors in a dense integrated circuit has doubled approximately every two years”, we may one day have a computer that is powerful enough to host a simulated reality of its own. 
If virtual reality is created, who’s to say that the virtual reality is not an actual reality? What if they create a virtual reality in which every single detail is exactly the same as the reality we are in right now? If this is done, than who is to say that the reality that we live in is real and the simulated reality is not? If two things are exactly alike, it wouldn’t make much sense to claim that one is real and one is not.

If they could somehow begin to record every bit of information on earth, where every molecule is, which direction it is going, than they could simulate that in a computer and that simulation would be a reality of its own, because it would be exactly the same as our reality. It would be a parallel reality. If this is every done, then ten years down the road, they would be able to create a virtual reality that is exactly like the reality of the day that virtual realities were created, or they could create a reality that was exactly like any day they chose, as long as that day comes after the day they began to record every bit of information. Anyone who chose to be hooked up to this simulation and thrown into that virtual reality would be traveling back in time to that moment. Sure they wouldn’t be traveling through time in this universe but they would be jumping to a parallel universe in which the time lags behind our universe by however many days they chose to go back in time. And when they are disconnected from this simulation, they would be jumping forward in time, back to our actual universe.


If we had all of the information in the universe, we could simulate our universe in a computer, thus creating a whole new universe. Not only that, but we would also be able to predict the future for the rest of time. We could then back trace this information, for example, if we took a snapshot of the universe at one moment in time, and had every bit of information about the universe at that moment in time, we could start to look back in time by ask the question “what circumstances would have lead the universe existing as it does within this snapshot?”. And this would allow us to calculate the information needed to produce a snapshot of the universe at a moment in time before we took our original snapshot of the universe. This process would then be repeated over and over again until we reach the very beginning of time. We would then know everything there is to know about the universe from start to end. We would know exactly what happened, or what is going to happen at any moment in time from the beginning of time to the end of time. And once we have all of this information, we could simulate any point in time within a computer and create a virtual reality of that place and time. This would allow us to, in a way, travel back and forth through time. All one would have to do to travel through time would be hook themselves up to this simulation and exist and think in this virtual reality. Not only that, but we could modify the code to change the simulation to create universes with completely different laws of physics. We would be able to create any kind of universe that works however we would want it to work. 

If the above is possible, then every universe is a multiverse and every universe could spawn an infinite number of universes within it.