Ok, let’s say that one day time travel does in fact become a reality. What happens to the person who travels back in time? Wouldn’t the person who is going back have the past then become his future?
Is time purely subjective like this and based upon the pov of the observer? Or is the past always the past and not sometimes the future?
Would someone’s own past become their future?
If I’m not to clear in what I’m asking here a situation. A guy builds a time machine (this is in his past) and goes 100 years backwards in time. Was the time machine built in the future or was it built in the past?
short answer: we don’t know for certain… Time travel gives a lot more headaches than you’ve even let on giving rise to djinn particles and other strange crossings of worldlines that don’t seem to make sense to our causally imprisoned brains. Fact is, until someone does travel back in time, we won’t really know how the past is causally linked with the future. It could be that you simply enter an alternative reality (the parallel universe hypothesis) or that there is some strange orthodox determinism that will prevent you from preventing yourself from ever being born.
My take? It’s probably going to end up being a timeless question.
While time travel may be a great premis for a movie or game in real since it’s a huge mathematical problem. The concensus seems to think one of three things.
1.) It’s not possible.
2.) It is possible.
3.) Well, not exactly.
Ok, lets address these in order.
1.) It’s not possible.
Their reasoning is usually, “If it were possible, wouldn’t it alreay happen? Since it hasn’t happend, it can’t.” Not very scientific but it has it’s logic.
2.) It’s possible.
Say we can alter time, or the time stream. How would we know it was changed? To us, it would seem that time is flowing normal, but to the traveler he would notice great changes. Maybe Einstein didn’t orignally discover atomic power and WWII carried on for 10 more years. Someone goes back in time, explains to Einstein (or replaces him) the error of his ways and history (the future) is changed. Since we lack the travelers “objectivity” we don’t see the change.
3.) Well maybe.
There is a theory called the fractured dimension theory. Imagine you go back in time and make a change, have YOU really changed anything in YOUR world or have you created a whole new one? If you changed YOUR world, how did you build your time machine? How where you borne? More than likely you’ve crossed univeral barriers. It is said that there are infinated universes where every possibility is carried out. Mathematically you’ve simply crossed over into one of these other dimensions, weather directly or not.
I’ve heard serious scientists say that if time travel became possible then you could only travel back in time to the day the time machine was invented. Why some think this would have to be so I couldn’t say.
Obviously this is one of the problems with time travel…causality gets all screwed up. One way around this might be that you are actually travelling to parallel universes essentially finding the place that is the time you want it to be so you don’t mess up any given timeline. Of course, parallel universes are nearly as big a pill to swallow as time travel.
Finally he had the time machine assembled. He was absolutely sure it would work. However, the prototype could only travel back in time.
He took a deep breath, and pushed the button.
He took a deep breath, and pushed the button.
He took a deep breath, and pushed the button.
He took a deep breath, and pushed the button.
He took a deep breath, and pushed the button.
He took a deep breath, and pushed the button.
He took a deep breath, and pushed the button.
He took a deep breath, and pushed the button.
He took a deep breath, and pushed the button.
He took a deep breath, and pushed the button.
He took a deep breath, and pushed the button.
…
That sounds ghastly, Two Stones (or is that two great beer mugs?).
I like to think about how the world would be different if it ever became possible to travel to the local past. History, I think, would be very much homogenized by “trade.” Steam power, the atomic bomb, relativity and quantum mechanics would be understandable to any educated person, no matter when (s)he lived. The idea of “discovery” would be nonsense, because every technology, even time travel, just is.
Obviously, this isn’t the kind of world we live in. It might be said that the instant somebody builds a time machine, history will change: the world will become as I just described, and will have always been that way.
But I have trouble with that idea. My assumption is that if anybody ever traveled into the past, it is, and has always been, in history. Not added to history at some bizarre fork in the universe, put there only because it is necessary to avoid the headache of “It was so” AND “It was not so.”
Perhaps I need to wake up and smell some cat in a box… and then I can accept the idea of a plastic past (and future).
Until that time, I think this:
Sending exotic particles back in time? Probably.
Sending exotic particles back in time in such a way that they can carry information? I wouldn’t be too surprised, but unlikely to be in any way that would let you send an e-mail to yourself two weeks ago.
Sending a compact disk back in time? No.
Most of the fiction about time travel assumes some sort of instantaneous or extra-dimensional travel from the subjective viewpoint of the traveler.
It seems far more likely to me that if time travel is invented, it will not be instantaneous or extra-dimensional, but more like the time machine in Wells’ Time Machine. The time traveler actually had to travel through the time.
But the time machine would have to move faster than the speed of light to avoid colliding with itself in the past.
What it boils down to is that in order to have a time machine, you must be able to have a local pocket of negative entropy. In other words, in order to be conscious of moving backwards through time, your brain would have to be firing backwards to an outside observer. The pilot of a time machine would look like a backwards movie to people outside the time machine.
The problem with this is the instantaneous creation of information when the time machine turns around at the end of its journey (in the past). This is what produces all the paradoxes.
So in order to have time travel, we have to allow for the instantaneous creation of information. This is sort of like the heavy hand of God. It is something from nothing. Out of nothing appear two time machines – one is turned off and traveling forward through time, and the other is operating, its pilot like a reverse movie. Where did they come from? God must have created them.
The pilot in the idle time machine gets out, and he is like a messenger from God, with information about the future. But from our perspective, it is not so much that he is telling us what the future will be like, it is more that his words cause the future. By observing him, the future is set, for he has already observed it. All the world contrives to make his words true, including his reversed double in the activated time machine. It could be no other way than how he observed it, for that is how the waveform collapsed for his observation. All other possibilities are destroyed when we observe him as he steps out of the time machine.
