I am fascinated with concepts such as time travel and parallel universes. But I disagree with Stargate SG1/Continuum's interpretation of the theory of time travel. For instance, if one travels back in time and changes an event, it doesn't follow that the future time line would simply begin to vanish and shift before people's eyes as it did in the movie. If time is in fact linear in this fashion, it would follow that people would be utterly unaware of the time line shifting. (I wish I could post a link to the specific scene I am referring to).
Imo, if one travels back in time and changes an event, it would not alter the exact future he or she came from, but rather it would simply create a new time line. In fact, I do not believe in time travel in the conventional sense of the term. The past has already happened, and the future is not yet so, thus travel to a place that no longer exists, or does not yet exist is impossible.. Unless all time lines exist at every moment in some form.
Just a few thoughts on the matter.