WARNING: Scientific speculation and highly geeky content follow.

We are getting close to the end of Lost, and for all those who have followed the show you know that one of the things that have been working with is the concept of time travel. This last season has featured an alternate timeline for the passengers of Oceanic Flight 815 in which they all seem to be doing much better in their lives. Another main theme that is currently in the show is a flashing from one timeline to another when events of those timelines come close to matching one another. What is going on here? How do you jump from one timeline to another without first going back to the point where the timelines diverged?

What I believe the creators of Lost are trying to touch on is a 5th dimensional jump. For the science geeks amoung us, this is a familiar concept but I will try my best to explain it here. Most people are familiar with the 4 obvious dimensions of our Universe, 3 for space and 1 for time. We are constantly moving forward through time, but that isn't a guarantee in Hollywood, which is what Lost takes advantage of. What you need to understand about time is that every decision we make causes us to take a different path in life, creating a different timeline.
Picture two strings that touch each other at one end, lay along side each other, but are separated at the other end. The point at which they touch is the moment of choice, when you decided whether or not you were going to have Pizza or Chinese for dinner. Both realities exist until you make a choice, at which point your current timeline becomes known to you. What is happening in Lost is two alternative timelines crossing over one another, with one affecting the other. This is called a 5th dimensional movement, moving from one timeline to another without first having to go back to the moment where the two lines diverged. This is what we are witnessing in the flashes that the characters keep having - cool huh.

This is kinda far out there, but keep in mind that it has been shown that there are up to 10 dimensions, so movement in 5 seems reasonable enough. In any case, it makes for great television and an interesting end to a great show. The series finale of Lost happens this Sunday, I hope you enjoyed my explanation. I also hope I didn't spoil it for anyone.