In io9’s article Can You Escape Your Fate? Science Fiction Has The Answer!, they delved into the idea of whether time traveling and changing your destiny is possible:
So here’s the part where we settle the question of fate vs. free will once and for all. Ready? Okay. The bottom line is, in order to predict everyone’s future actions absolutely, you would need an infinite amount of data. You would need a model of the universe the size of the universe. And you can’t have time travel without the ability to change the timeline, or else you couldn’t interact with the past at all. You’d be unable to touch anything or move anything, even minor things, because it’s all part of established history. You couldn’t even disturb the air molecules or step on anything. And if you can change the past, you can change the future. Any questions?
And the first commentator after the article quoted/paraphrased Peter David:
You simply cannot really travel into your own future or past. Like the basic law of physics that “two objects cannot occupy the space at the same time” neither can you go into your own timeline…
So, you’re better off accepting who you are, right here, and NOW! You losers!