I have always been interested in the nature of time travel, and after having a dream a few years ago in which I met a future self who warned me of impending danger (That old chestnut,) I developed this theory. Now, I haven't really done scientific research on this, so if it already exists, I apologize for taking credit for it. Also, if you find any glaring theoretical errors, feel free to make fun of me.
Alright, check this:
Ever see those movies where there are two time periods happening at the same time? I'll use a crappy movie as an example. In the movie Frequency, a man uses a radio to talk with his father in the past. I forget the exact event, but at some point, the man needs something, let's say, a gun. The father takes the gun, and buries it under the floorboards in a certain room, where it suddenly reappears in the present timeline for the man to use. I don't quite agree with the movie, but it helped me make the theory.
Each and every second of time is its own isolated dimension. Instead of Time moving on, we're just shifting dimensions. Thus, every moment in time is happening at the same time, just across different dimensions. It's like a bad episode of Quantum Leap. That is how the son can talk to his father - it isn't that his voice is traveling through time. His voice is traveling through dimensions of time to other periods that are happening at the same moment. So, time travel, therefore, isn't the ability to send someone back in time. It's the ability to send them across dimensions to other moments.
I don't know if I can explain it a lot clearer than that. And that's not too clear. But it does help prove some anti-time travel theories wrong. Lots of people, when faced with the issue of time travel, fall back on the same question. "If time travel were possible, why haven't we been visited yet?"
First of all, who’s to say that we haven't? (See John Titor) But, closer to my theory, since all dimensions occur simultaneously, what happens in one directly effects what happens in others. Like the father who hides the gun in the floorboards for his son to find, something that happens now instantaneously affects future dimensions. Therefore, until we create a time machine in a present dimension, one won't exist in future dimensions. However, the second a working time machine exists, it will exist in all future dimensions, and we will suddenly get a huge amount of travelers visiting our dimension.
This begs another question, however: The second we create the time machine, it will exist in the future, in which case, visitors are bound to go to the past, and show them the machine, so our present reality would change, and everything would suddenly combine into one reality and one dimension of everythingness. The time machine would connect all the dimensions, so, conceivably, either the world would end, or it would change forever. Time Machines could be the new modes of transportation; Dimensions could be the new cities. I can see it now:
"Those are great pants! When did you get them?"
"I got them in 2004.05.31.11.49.36"
Alright, maybe it's a little farfetched, and maybe I'm just a dumb kid with crazy theories based on nothing, but at least it’s something crazy to wrap your mind around.