Time Travel (Because that hasn't been done before)

[Slyvena]

There are alot of theories about time travel. This is a theory about time travel. If that thought bores you then stop here.

We can all agree there are some novels/movies that handle time travel intelligently and with great nuance enhancing a story, then there are others that exploit time travel to hide a lack of plot coherency or sloppy writing. The first time I read one of the latter books, I set out to form 'my' theory of time travel, of course when reading a good book you put your theory to the side for a time, but I like having a sensible baseline.

Okay, so I'm pretty sure this will have already been thought of by someone else, but here is a theory about the mechanics of time travel that eliminates all those pesky paradoxes (I'm looking at you grandfather paradox) and other annoying confusing elements of time travel, simplifying it into a form that can consistently follow its own rules.

Here's the rundown, the theory comes from a small set of assumptions, the mechanics of how time travel would play out are inferred from those assumptions.
(Diagrams coming)
Assumption:
1: Time travel is easy/feasible non-deadly etc
2: Time travel is instantaneous (There will never be more than one time traveling event at any point, you won't 'run into' anything)
3: The Timeline instantly and completely rewrites itself when time travel occurs (Sometimes called time lag or waves, there is no of this)
4: There is no absolute timeless identity. (If YOU meet YOU from another time, you are both separate entities, able to interact as any other people would with no special rules)
5: Fate/Destiny does not exist, all time and events within it can be changed.

Okay, here is a terrible picture.

Blue Bar = Timeline
Gold Star = You with your time machine.
Arrows/Moving Star = Time Travel event
Faded Blue bars = Destroyed/Erased Future.
Green Bar = New part of timeline.

First event is a time travel backwards, Second event is a time travel forwards.
The red line indicates a period in time in which you did not appear at all on the timeline, you vanished thereby changing the future, then reappeared at the end of the red line.

Spoiler

Now as far as I can tell, this is a pretty air tight way to work things, if you think about something the answer as to what would happen is obvious and singular.

(I deliberately thought up some complex time events and the way they played out seemed pretty straight forward, for the sake of simplicity I'll leave them out for now)

Input? Comments? Random Gibberish? "Oh my gosh Slyvena, you helped me so much, here let me give you lots of money"?

 

[Tallim]

I'm not entirely sure exactly what you are trying to show here.

I also think your diagram is wrong as when you travel back you aren't travelling from the new timeline at all, you'd be travelling from the broken timeline and then travelling forward along the new timeline.

Which is pretty much the way Back To The Future explains it.

I just don't think you've expressed your idea quite clearly enough. Or it's just too early in the morning and I'm not awake yet.

 

[Keoul]

1: Time travel is easy/feasible non-deadly etc
2: Time travel is instantaneous (There will never be more than one time traveling event at any point, you won't 'run into' anything)
3: The Timeline instantly and completely rewrites itself when time travel occurs (Sometimes called time lag or waves, there is no of this)
4: There is no absolute timeless identity. (If YOU meet YOU from another time, you are both separate entities, able to interact as any other people would with no special rules)
5: Fate/Destiny does not exist, all time and events within it can be changed.

About number 2, what do you mean by "There will never be more than one time traveling event at any point, you won't 'run into' anything"?

The Multiverse theory seems like a "cleaner" version of what you're trying to explain, time travel simply branches off into another timeline and the old timeline is deemed a "doomed" timeline.

 

[DoPo]

Yeah, I'll just echo the problems mentioned so far - travelling back in time would not take place from the new timeline (I assume you know that, just amend the diagram to be more clear) and what does the second rule mean?

5: Fate/Destiny does not exist, all time and events within it can be changed.

Somewhat related here (maybe also 3., depending on how you view it) how would you explain the ability to travel to the future? It doesn't seem plausible from what we have so far, since there isn't anything set so far, aside from the past, if you look at the moment the timetravelling event occurs. Unless the future is predetermined.

 

[Spade Lead]

Your diagrams should look more like this:

Backwards Time Travel (Top * to Bottom * then continuing on from Altered Timline at Bottom *)
_____________*
*---------------

Forward Time Travel (For Time Period --- You do not exist)

_____* ----- *______


DAMMIT YOUTUBE, WHY DO YOU NEVER HAVE THE CLIPS I WANT! Watch the episode of Family Guy called "Meet The Quagmires."

Brian basically says what you are trying to say with a way easier to read diagram drawn on a chalk board. Or watch Back to the Future. Or you know, just learn to draw better diagrams. A line diagram would have been way easier to understand.

 

[Kalikin]

There are a lot of very intelligent people who believe, or at least strongly want to believe, that time travel is possible. Personally, I think it's silly because very complex models of why time travel is thought to be possible can be taken down with some very simple interjections.

For instance, you would have to accept backwards causality. That is, any state regarding yourself before you time travel would have to hold true "before" the cause of them. Say I cut myself and then time travel back a bit. That cut would still be there "before" I cut myself. Sounds kind of silly to me.

However, if you were able to somehow step "outside" the timeline so that it's only you that isn't affected, you run into other problems.

Firstly is the "no destination" paradox. This states that for you to travel, there must be a place to travel TO. So where does the past "exist"? It would require that the past is recorded somewhere, existing perpetually, like a video.

Then you have the twin paradox. If "you" aren't affected by time's reverse, then there suddenly becomes two of you. What happens when you return to the new future? That other "you" would not simply vanish, it would be a separate entity.

Finally, if you view time as a "line" that adapts itself constantly, then you're forced to accept that your memories from a moment ago are "false", or are constantly changing. I remember typing out this giant post for the last five minutes, but if the timeline is constantly changing, then what was I REALLY doing a moment ago?

Things get even more complicated when you consider that it isn't only one person time traveling...

 

[Popadoo]

I think that if Time Travel does exist, then its of the theory that any time travel that is done transports you to a parallel universe, therefore doesnt change anything in the universe you "left." So if it did exist, then no one would ever know but the person who travelled because they would be in a different Universe.

It eliminates paradox, meeting yourself, etc...

Similar to this.
With our current knowledge of general relativity, and space, and other almost sci-fi-esque stuff that is actually probably true, nothing is preventing time travel from being possible.
It's just very very very very very very hard to do.

Also, if we did go back in time and say, killed our grandfather... nothing would happen. There would be no paradox. Simply by BEING in the past you've created a whole alternate universe, a new timeline where you were in the spot you traveled to at time you traveled to. You are cut off from your own universe, the universe you came from. And in THAT universe, your grandfather never died, he brought you into the world, but that universe has no affect on this one. You've just created a new timeline where there are slightly more atoms than the other, those atoms being YOU.

 

[Daverson]

The fact of the matter is, all time travel science is theoretical. Heck, for all we know temporal causality might not even be a thing (ie, you can have an event happen today which isn't set in motion until tomorrow). Until we observe something actually travel backwards in time, any equation, theory or idea about how time travel should work is inherently flawed.

 

[Shocksplicer]

Methinks somebody just got around to watching Looper...

 

[cerebus23]

Only thing they know is that there are no laws against traveling backwards or forwards in time, no applicable laws of physics preventing it.

Thats why people try and guess the hows whys and what ifs. That and everyone has regrets even scientists .

If time travel was ever discovered god help us all if we are on one fixed timeline people would make a royal mess of things.

Probably there are laws in place preventing things like paradoxes and ending the whole of time space because mucking around you broke something. Natural systems to either negate many of the assumed problems with time travel, or prevent them in the first place.

I tend to believe we are bound to our own particular timelines, like we cannot jump out of our time into another times reality, if they exist, and we are bound to that, quantum leap took it further and their take on it was you could not jump outside your own life period, interesting idea, since how can you go back in time before you are born anyway paradox thing.

So i guess it comes down to how beholden matter is to their temporal place in the universe. If you can shift matter out of its time does it stay bound to its time in some way? or does it create its own "reality" and can freely move about anywhere in time? It would make a huge difference on the hows and whats of time travel if we could figure that out.

 

[DoPo]

Say I cut myself and then time travel back a bit. That cut would still be there "before" I cut myself. Sounds kind of silly to me.

...I fail to see the issue here. Let's expand this example and see if I got it right: you cut yourself in the morning, then travel to yesterday. Yes, the cut would persist. The time travel event would mean nothing, since from your viewpoint, it would still be after the cut. Here is a sample event timeline from your perspective:
1. Wake up.
2. Have breakfast.
3. Shave and cut yourself.
4. Travel back in time.
5. Do more stuff.

At no point would your body need to reverse to an earlier state.

Unless, you mean "travel back in time" as in "reverse time", similar to how you'd rewind a tape. In which case, I have no idea why you assume the cut would persist. That's how Prince of Persia did it but I somehow doubt they went for "most realistic" portrayal of time travel there, as opposed to "whatever would work for our game".

 

[Slyvena]

About number 2, what do you mean by "There will never be more than one time traveling event at any point, you won't 'run into' anything"?

The Multiverse theory seems like a "cleaner" version of what you're trying to explain, time travel simply branches off into another timeline and the old timeline is deemed a "doomed" timeline.

I mean for example if someone traveled in time while you were vanished (future traveling), and they traveled to a point before where you were set to reappear, then you never would, because the future where you reappeared no longer exists.


Yeah, for some reason I don't like multiverse, I prefer a singular changing universe.

Yeah, I'll just echo the problems mentioned so far - travelling back in time would not take place from the new timeline (I assume you know that, just amend the diagram to be more clear)

Yep, it was a pretty shotty diagram, you stated what I was trying to illustrate.

Somewhat related here (maybe also 3., depending on how you view it) how would you explain the ability to travel to the future? It doesn't seem plausible from what we have so far, since there isn't anything set so far, aside from the past, if you look at the moment the timetravelling event occurs. Unless the future is predetermined.

No so much that is needs to be predetermined. It works if you look at time travel as being a distance traveled rather than a destination aimed for, going back is easy to understand. Going forward is almost like just waiting above the timeline and letting it pass until it reaches the point you want and then plopping back in (of course if someone changes something while your hovering then you'll be gone forever... so, not a good idea)

I think that if Time Travel does exist, then its of the theory that any time travel that is done transports you to a parallel universe, therefore doesnt change anything in the universe you "left." So if it did exist, then no one would ever know but the person who travelled because they would be in a different Universe.

It eliminates paradox, meeting yourself, etc...

It does remove paradoxes etc, but it isn't really time travel, it's just sideways universe travel, not really time travel at all. Hence the one singular but alterable universe theory in OP. But yours would work too.

Finally, if you view time as a "line" that adapts itself constantly, then you're forced to accept that your memories from a moment ago are "false", or are constantly changing. I remember typing out this giant post for the last five minutes, but if the timeline is constantly changing, then what was I REALLY doing a moment ago?

Pretty sure all the other paradoxes are actually easily resolvable in OP or from other commenter (if your using a different system then well, yeah), as for this one, assumption 4, no timeless identity. Meaning if the past has changed so will your memories, unless you are the one that traveled in time your memories change from cause and effect like any other normal person.

So i guess it comes down to how beholden matter is to their temporal place in the universe. If you can shift matter out of its time does it stay bound to its time in some way? or does it create its own "reality" and can freely move about anywhere in time? It would make a huge difference on the hows and whats of time travel if we could figure that out.

Yeah, pretty much agree with you. Myself I think time travel is completely impossible, altering it's speed, that's done all the time however haha.

Methinks somebody just got around to watching Looper...

Haha yes, that's where the assumption 4 was inspired from cause I was like "that's stupid"

 

[uhddh]

I think that if Time Travel does exist, then its of the theory that any time travel that is done transports you to a parallel universe, therefore doesnt change anything in the universe you "left." So if it did exist, then no one would ever know but the person who travelled because they would be in a different Universe.

It eliminates paradox, meeting yourself, etc...

In other words he subscribes to the parallel universes theory. As do I.

If you went back and altered something, even something minor, in the timeline, two universes would split off. For example if you killed someone (we'll use Hitler as always), there'd be tw universes, one where WWII did occur and everyone died (aka our universe) and one where WWII is non-existent (or at least it's not our WWII). It's a strange twisted theory. If you travel back in time, you don't travel to a different universe, you simply create a different universe.

 

[Ledan]

I prefer to view time travel as a specific type of dimensional travel. You are travelling to a different world, that is identical in every way to how the world was at that time. Except now you are there. Thus, you could see a rock that you want to move, go back in time and move it, then go forwards in time again.
You wouldn't run into the paradox of there not being the rock there to cause you to go back in time. 3 different dimensions.

 

[Canadamus Prime]

The only one of those I agree with is #5, nothing is certain. So even if you met your future self and he told you all about the events to come that wouldn't guarantee that events would turn out as he/she described them.

As for the rest I subscribe to the Doctor Who theory of Time Travel, ie any Time Travel events that will ever occur have already occurred. (Timey Whimy Ball)

 

[Daaaah Whoosh]

I don't see how travelling forward in time would disrupt anything. The fact that you chose to use a time machine was not caused by any sort of time travel, it's simply a normal, everyday choice. If the time from the point of using the time machine onward is erased, it'd be like saying that me choosing to write this post has just destroyed the future. Which, I suppose is a possibility, but not exactly a nice one. I like to stick to the infnite universes theory, where the universe splits up every time there's more than one option. That way, every decision you make doesn't annihilate the future, it just makes more of them.

 

[HardkorSB]

Firstly is the "no destination" paradox. This states that for you to travel, there must be a place to travel TO. So where does the past "exist"? It would require that the past is recorded somewhere, existing perpetually, like a video.

This was always my biggest problem with time travel.

A few other things:

1. In space, you experience time differently than on Earth and even on Earth, apparently time goes by differently on different altitudes, at least according to several scientists but for the sake of my argument, let's assume that time is indeed relative. That already creates all sort of problems.

2. We can measure time by observing various events occurring. The hand of the clock moved by this much therefore this much time has passed. The organic material has decomposed this much therefore this much time has passed. The radiation level has changed by this much therefore this much time has passed etc.
But is that happening to the universe as a whole or just to the things in the universe? Maybe time isn't a real thing and we just made it up to measure the "distance" between events?
If this is the case then the only way to travel back in time would be to reverse all the events in the universe without you actually reversing along with them (which, with some veeeeeeeery advanced technology, would maybe be possible on a planetary scale, perhaps larger but not on a universal scale, not by us anyway) and to travel forward would mean to preserve yourself intact while events around you occur normally (which would actually make cryostatis a form of time travel into the future, I guess).

 

[micahrp]

Seems like I've been here before, but I'm willing to repeat past mistakes.

Time is a measurement of change in a system, therefore all time travel would be manipulations of change. If you wish to travel forward in time, stop change in yourself until the rest of existence reaches the state of change you wish to be at. To travel backwards just take apart all existence and reassemble it in the state it was at the point in the past you wish to be at. Since you omitted undoing yourself the previous you won't be there unless you cheat and use some excess space dust to make a spare earlier you (should be easy after dissassembling and reassembling all matter and energy).

Beyond that yes, all your thoughts on what will happen around the "travelling" part fit.