Bahh, I got called a stupid **** at the quantamn physics board for this notion, but then I served them a can of "wisdom" whoopass when I meationed how we all are just theorizing as it's not like any of us have been through time to prove the reality of it..
What I believe is time travel as we know it is IMPOSSIBLE. For one, you would have to travel faster then light, or alternatively, make space-time move around YOU, goodluck with that.
If you manage to pull one of those off, I believe you'd only be able to go into a distant future, I don't even think you'd be able to caculate how far, not that it would matter. Because only two scenarios would happen..
A) Like Sliders or Dragonball Z, you would be transported to an alternate timeline much like the one you left, but sense space-time had to fold around you, it's a completely differant continuam, and unlike those two series I don't think you'd be able to get hime.
B) Like Star Trek, you transport to the future only for there to be nothing at all. Because nothing has happend yet. Time has to catchup with you. Which could take litteralty eternity.
And traveling to the past would be even harder to do as I would think you'd have to go SLOWER then time..
So wether or not time travel is possible is not the question, the better question is it practical? And no, no matter if it was less grim and doom as I intterputed it, it would never be practical and therfore should be discarded along with many other Dr. Frankenstien ideas such as fetus stem-cells and cloning.. To lesser extents ofcourse..