Time Travel?

[Kurt_]

Unless you travelled back in time and secretly helped him escape, leaving a clue for you to later realise it was you. Then later, hearing a story from him, realizing that it was you who saved him, travelled back in time to save him, leaving a clue for yourself?

That doesn't make sense. Or does it?

To change something in the past, you would have to travel back in time without any knowledge of what happened in the past. Get it?

So that when you travelled back, the thing you changed hadn't happened yet, and you realised that you had to change it, and knew you could because it was already changed. Like in Harry Potter (I know, lame example but the best one) where he kills off the dementors or something and saves himself. I'm nnot a hardcore HP fan so I don't quite know what I'm talking about. It was in a movie.

[Gamelver]

Or it could be that the timeline is static, and that if we ever DO achieve time travel we won't be able to change anything because it will have already been changed.

For example:

Ted's friend, William, was stabbed to death in the past (Either one week or several years, whichever you prefer). Ted goes into the past to warn William that he's about to be stabbed to death in a dark alley. William avoids the dark alleys and lives. However, now Ted doesn't have to go back in time to warn William that he's going to die, and he doesn't, and william dies.

So unless William can both live and die in the same moment (time travel to a parallel universe?) time travel is not possible except for observing. Only looking, no touching.

actually, I don't think it works like that...I think that if you go back in time and you prevent Williams death, you create a new timeline. Watch Back to the Future Part 2 (yes, it's a movie, but the Doc kind of explains it pretty well in one part ). Anyway, there are two possibilities, right? William dies, or William lives. If Ted does nothing, he obviously dies. If Ted goes back in time and prevents his death William lives. Now, even if Ted were to go back to the future (like the movie ...) it'd be in a timeline where he prevented William's death (and, consequently, could change quite a bit in his world).

Harry Potter got it wrong, anyway. You see, in the REAL universe, Harry would not have survived the dementors, and therefore could not be in the future to go back in time to save himself.

[Nicholai]

Looks like no one likes you now, sam. Learn to be nice.

[project_failure]

Like elementxmaster said time travel is dangerous. I have a theory that no matter how bad something seems it was for the best. you see lets say that your grandma dies. Now as far as the history books are concerned your grandma was not significant. But due to some far out reason your grandma's death is indirectly (and i mean really indirectly) responsble for North Korea never obtaining a working Nuke. Okay, I know sounds rediculous but bear with me. So, you build you time machine years later and go back and save your grandma. But consequently North Korea obtains a working nuke and drops it on L.A. There for every thing was better if left alone.

Note that this theory does not mean that every change will have quite such a big negative reaction, but a negative reaction none the less. If I sound like an Idiot think over the basic idea of the theory not my extremely exagerated example.

wow three words starting with ex in a row.

[sam fisher]

Looks like no one likes you now, sam. Learn to be nice.

I don't care, learn some basic time travel related physics.

Gamelver has explained it perfectly. Go and watch that 'tenth dimension' thing for a fairly in depth explaination.



That demonstrates a 5th dimensional view on a example timeline. Once ted has made his choice he is in a completely different timeline. The only thing he could do is travel back in time to before he changed the timeline originally and do it differently to obtain a different future.