How does time stop when approaching the speed of light. Isn't "time" a constant? I think it would appear to stop, and your atoms or whatnot would react in a different way, but time would still be going at it's normal speed.
Also, I don't see how time travel could be possible, because to me, the universe, at every trillionth of a second(or smaller) is in a set state. Quarks are in a set spot in that moment, as are atoms, molecules, people, planets, fish everything.
If there were some godlike being, outside of the constraints of time that could take a snapshot of every moment(every trillionth of a second), how can traveling forward or backwards in time be possible? Or simply put, how can you do something you never did, or not do something that you did? It seems like if either of those occured, you'd be destroying a universe, because what existed at one moment in a particular point in time no longer exists at that point.
I thinkk parallel universes are possible however. What would appear to be time travel would be going parallel into a universe that resembles our own. Something would be different however and if a person found out what it is, they'd automatically think "oh i changed my past/future" when they actually didn't
Oh I could go on. I love talking about sci fi stuff.