> If time travel were at all possible...wouldn't somebody from the future have come back and told us by now?
>
> The Other "Maybe I just missed it, or something" Matthew

I'm pretty sure that time travel will never be possible, or there will be something like the Temporal Security Agency to prevent people from modifying history. Unless actual time travel made it impossible to modify history, I'm certain that somebody would manage to mess it up in a way that would either wipe out the human race or some such thing, like dropping nukes on primitive human civilizations or something. And if that happened, unless there were some odd coincidence which nullified that, I wouldn't be typing this post right now. And, if there were some odd coincidence, there's probably a good chance that doing something else like shooting your parents would cause exactly the same type of coincidence, so it wouldn't matter anyway.