After watching alot of Doctor Who, playing Prince of Persia, and just generally being in geek mode.

If it were possible to travel in time, say for example to the past and change something, ultimately changing the course of the future, would an alternate time line be created?

For example, I was born in this timeline, but if I went back a changed the past, which stopped, say a grand parent meeting the other grand parent, stopping one of my parents being born, stopping me being born, yet I still exist because I'm in the past, would that create two seperate time-lines, or two seperate dimensions? Because if I travelled back to the future, I shouldn't exist because I was never born, but yet I'm still living, breathing and fucking with time. So if I was able to create a dimensional shift device, and used it, would I be able to come back to the time-line where I was born?

If this makes any sense what-so-ever or if you see what I'm trying to get at, what do you think?

Would I just fade away in the past, or because in my time I was born and travelled back, would've I created two seperate time-lines, parallel if you will.

So for example, the Terminator movies, because time is fixed and the events happened, each Terminator sent back to kill Sarah/John Connor would've always had no chance of succeeding in their missions?

Sticking with the Terminator example, T2, they think they'd prevented Judgement Day by stopping the cybernet research before it was completed, meaning the nuclear strikes didn't happen on the date they should've. But because time is fixed, it happened anyways in T3, so there was only a subtle change in the timeline, but because it had happened in the future, it was always going to happen, no matter what they did in the past.

That a good analysis of what posted? Or have I missed something.


Stuff like this really interests me, maybe something we never ever get our heads round because it will probably always be impossible to go back/forward in time.

A time loop would be created. Having effectively killed yourself as a child, you wouldn't have lived to go back in time, so you would have been able to effectively kill yourself, so you wouldn't have been able to kill yourself, then you would have been able to kill yourself, then you wouldn't have been able to kill yourself, then you would have been able to kill yourself, then you wouldn't have been able to kill yourself, then you would have been able to kill yourself, then you wouldn't have been able to kill yourself, then you would have been able to kill yourself, then you wouldn't have been able to kill yourself, then you would have been able to kill yourself. See where this is going. Time wouldn't allow a parodox, such as meeting yourself, so Bill and Ted's excellent adventure has a time loop. The example given here would stop time, and end everything, as time wouldn't be able to fix the problem. The time loop would never end, as there would be no time. It makes sense. Eventually.

It wouldn't be broken, merely delayed in it's quest for reaching it's end. If you really think about it, and bend it a bit, a person wouldn't do the same thing twice in a row. However, I am applying the Tenseless Time idea, and if all things have happened, and will always happen, then Time wouldn't have let it happen. Time is a really tough thing. If Churchill wore a 'tash, would things be different today? No. If Hitler hadn't been chucked out of that Austrian college, would there have been WW2? Yes, just in a different time/place. It all springs out eventually. But if someone went back in time and killed the first rabbits, would time spring back? No. Would you go back to kill a non-existent creature? No. So we get a time loop. Once time fixes, it continues to the next problem. Like me in a maths test. Solved problem, on to the next. You see yet?

I agree with ness on most of what he's said so far.

this is just a theory that i like:

keeping in mind that the universe is just an arrangement of mass and energy in a certain proportion at any given time. that is, if you were to take a snapshot of the universe, a certain amount of it would be energy and a certain amount mass. it's all arranged in a certain way and that's how we perceive the universe. that being said, the next snapshot you take would be slightly different. maybe some mass has been converted to energy or maybe some energy back into mass. regardless, there's a fixed amount of it in the universe whether it be in the form of mass or energy. so it can be reasoned that there is an infinite number of ways that mass and energy can be oriented in the universe. now that's just for one snapshot. if you consider that time is constantly flowing, then for every moment in time, there are an infinite number of parallel moments with different combinations of energy and mass distributed differently throughout the universe. as they all happen in parallel, then yes this could be construed as parallel universes. but the issue with this theory is that there's no way to tell for sure that they occur in sequential order. that is, who's to say that they make sense in reference to eachother? one person or entity will experience a different 'moment' with that specific orientation of mass and energy at a time. we travel through this space time field experiencing moment after moment.

thus far, (in this thread) we've only really considered time as a line. but why not consider it in more than just one dimension. if you are travelling along the spacial time field, and you manage to somehow turn around, go back and change the orientation of some energy and mass (in this case, making it so your grandparents never meet), then you shift yourself horizontally or vertically in the field. your new time vector is no longer in line with the original time vector. so it's not like you would create a new universe or an alternate reality, more like you'd experience new moments in the universe that you hadn't previously experienced. if you were to relive a day (think the movie groundhog day) and you did things differently, they would be parallel moments of the same time frame. the moments you experienced previously wouldn't disappear, they'd just have a different orientation on the time 'map'.

the interesting conclusion is, we travel through time experiencing certain combinations of mass and energy, one for every moment of time. what if you were to hold time still. and then experience all the different combinations unique to that particular moment? you'd experience everything from the entire universe being a giant ball of energy, to the entire universe being a giant ball of mass and everything in between. incredible.