Well, I'm not sure where to put this, as it talks about time travel AND other dimensions. So I'll just guess and put it here.
The thought accepted here is that we have a four dimensional universe-3 dimensions of time, and 1 of space. 3+1=4, right? Wrong. Well, the equasion is right, but time isn't a dimesnion. Something else that is accepted here is that 1 dimension is two directions-in Flatland, Linelanders can only move left/right, and their universe is considered 1D. Flatlanders move left/right & forwards/backwards, yet their universe is considered 2D. Spacelanders can only move left/right, forward/backward & up/down, yet their universe is considered 3D. As you can see, 1 dimension=2 directions.
Now, this next part assumes a lot. But, time only moves forward-thats one direction, and if you can struggle the mathematical expertise involved here, that is only half of a dimension. Therefore, our universe is 3.5 dimensions. Now of course, this doesn't mean anything-it is possible that time does suddenly go backwards at some points and we just don't notice. It is also possible that time is 2D, and that moving across the 2ndD of time would take us to an alternate timeline, as (according to sci-fi) time is constantly branching out whenever something happens.
Now, this doesn't really do much for us, as time is irrelevant. Action+(Memory+Predictions)=Time. You get me here, right? Whenever something happens, we say time has moved, the past is nothing but our memories, and the future is nothing but our predictions and our natural reaction to guess what is gonna happen a few seconds before it does (reflexes). But, it gives us two things to talk about.
1. What would the third dimension of time be? The fourth? Etc.
But, more importantly, it makes me wonder, what would it be like in a world with bizzare spatial dimensions. Lets say, 1D-up, and forward. Or a 2.5D world, where you can move up but not down. How about a 2.3D world? A piD world, lol?