Faster Than Light-Based Time Travel

My apologies for the long absence. Work, school, holidays, and PROCRASTINATION have kept me busy doing everything but working on this website, and when I finally got around to writing a post, it turned out to be a much hairier topic than I expected, and I took almost two months to write it. But it is finally here! Enjoy!

One thing that has bugged me a lot about science fiction is what seems to be the prevailing theory on the faster than light (FTL) method of time travel. The common concept is that, because time slows down for an object approaching the speed of light, then if that object could somehow surpass the speed of light, then it would start traveling backwards in time. In more technical terms, what this is saying is that spatial acceleration in the direction of spatial motion is either the same as, or inherently tied to, temporal acceleration in the opposite direction of temporal motion.

But what this appears to neglect is the very relativity it is based on. From the perspective of the traveler, as the ship speeds up, time for the contents of the ship proceeds as normal, while time for the outside world speeds up. However, from the perspective of a stationary observer, time for the observer will remain stationary, while time for the ship slows down. As the traveler approaches the speed of light, time for the outside world will approach an infinite speed as time proceeds normally for him, whereas from the perspective of the stationary observer, the ship will stop experiencing time altogether, though it will continue moving in space.

Wow, does my brain hurt just getting this far.

This brings up the problem of traveling at the speed of light. Depending on the perspective we look at this scenario from, we get contradictory results: from the observer’s perspective, time for the traveler stops, but from the traveler’s perspective, it does not. In mathematical terms, time becomes undefined, because we are dealing with numbers that just don’t work with our math (try calculating ∞-(∞-1), and play around with the order of operations, given that ∞-∞=0, and ∞-1=∞, and you’ll see what I mean–math just doesn’t work here)

So traveling at the speed of light appears to be a mathematical impossibility, but we can conjecture what it would look like, as long as we limit our perspective. With that foundational understanding, let’s move on to speeds greater than that of light.

The easiest way to think about FTL speeds is from the perspective of an outside observer, so that is where I will start. An observer will perceive the traveler as experiencing time more and more slowly as he approaches the speed of light, ultimately ceasing to experience time altogether at the speed of light. Thus, it is only logical that, once the speed of light is exceeded, time for the traveler will reverse, and he will travel back in time. This is the standard view of what would happen if someone exceeded the speed of light.

But this is where things really start to get interesting: from the perspective of the traveler, time for the outside world is accelerating until, when he reaches the speed of light, time for the outside world is traveling at an infinite speed, so when he accelerates past the speed of light, why would time for the outside world suddenly reverse speed? There is absolutely no reason to expect this. In fact, our entire concept of time, even altered by Einstein’s Theory of Relativity, simply breaks down.

This concept contains two instances of paradox. The first is that relativity begins to affect time in completely different ways, depending on the perspective you choose. The second is the fact that travel at speeds greater than that of light cannot follow the same rules of relativity as speed up to that point.

I  hypothesize two possible explanations for this: the first possibility is that light speed is actually is an absolute barrier, and for more reasons than we realize. I still have no idea why the universe would behave this way, or if the scientific community has any theories. It seems completely arbitrary, but if I have learned one thing, it is that God does not do arbitrary, so there must be a reason. The second possibility, both less likely and cooler to think about, is that once the speed of light is exceeded, you begin interacting with the fifth dimension. I might be able to cook up some ideas on how that would work, but right now I think this post is long enough, and has been long enough in coming, plus it’s getting pretty late, and my this topic hurts my brain at my best.

What do you guys think?


Time Theory

My favorite genre of pretty much anything (books, movies, TV shows, etc.) is science fiction, which shouldn’t be a surprise, considering the subject of this blog. I particularly enjoy the ones in which time travel is a main theme.  However, every time I watch anything with time travel, I just try to accept its theory of time travel, because there are so many theories, and they all have problems.  So I was talking about this to a friend, and he encouraged me to make my own time theory, so that is what I am doing.  This is by no means set in stone for me, and I would love to talk about it in the forums.

The first order of business would be paradoxes. This is dangerous ground to tread, because they cannot exist, but time is not an entity than can prevent them.  So what do we do?  Well, let’s think about time as a set of dimensions. It is common to think of time as a fourth dimension, but what I am suggesting is, if only for argument’s sake, to think of it as a fourth and fifth dimension, so that basically, time has its own “timeline.” Every time a paradox is created, a change is made in time, and it moves time a little further along its timeline.

Another way to think of this is that every time a paradox is created, an alternate universe is created for that paradox to happen in. If this is the case, if a paradox creates a parallel universe, which universe does the creator of the paradox end up in? Well, the time traveler left his spot in time and moved to a different spot. If he then travels to the future, it will be his future that he travels to, which would be the future of whatever universe/dimension he leaves to go to the future. Thus, if he makes any changes to the future while he is in the past, his future will contain the effects of those changes. Therefore, if the time traveler creates a paradox, he is stuck in the version of the universe with that paradox. Following this line of reasoning, since the very existence of a time traveler in the his own past inherently makes some changes, however minute, to the world the time traveler left, it would be impossible to return to the exact universe you left. You might return to the same spot in your life, and you might not even notice any changes, but you would not be the same you your friends knew. As far as the world around you is concerned, a version of you left, and a version of you may or may not have come back, depending on the extent to which you changed the past, but the you that came back is slightly different from the one you left. Another facet of this is that there will be some versions of reality that have multiple copies of a certain time traveler (because the time traveler’s adventures in the past caused his future version to never time travel, thus leaving two copies of the same person in the universe) and other versions in which the time traveler left and never came back (because no version of the time traveler changed the past of this version of the time traveler to cause him to leave, thus the time traveler essentially dies to his family and friends when he leaves for the past.

There are a few fascinating things to note about this hypothesis:

  1. Each universe would be either
    1. full of perceived paradoxes, because the people who caused the paradoxes would be from a different version of the universe, so the paradox actually contradicts nothing, or
    2. completely devoid of paradoxes, but full of random people appearing out of nowhere. I am not sure which of these would happen
  2. Circular reasoning within time (going back in time and causing yourself to go back in time and cause yourself to go back in time, etc) is no longer a paradox, because every time you go back in time you enter a different universe. What would likely happen is that each iteration of time travel would produce a slightly different result, until the apparent circle reveals itself as a tight spiral within the overall timeline of time.
  3. Time travel would be very dangerous: not for you, but for those who know you. Depending on the history of your universe (whether there was a version of you that entered in the past who left his present under similar circumstances as you), you may or may not come back to those who care about you. Also, depending on how much you change (and/or how much the other version of you that entered your past changed) in the past, the friends that you come back to will be different than the ones you left (or the version of you that comes back to your friends will be different than the one that left)
  4. The existence of each new version of the timeline is dependent upon each previous iteration of the timeline, because if the “creator” timeline had been different, the created timeline would have been proportionally different. This reasoning is valid for each version of the timeline, either until the version of the timeline God originally created, or ad infinitum, depending on your worldview. Thus, because each version of time is connected to the previous in a continuous stream of timelines, it can be said that the timeline is actually experiencing change.

Now, change is relative. Any time something changes, it is changing relative to something. When a top is spinning, it is spinning relative to the things around it, but nothing on the top is changing relative to itself. All change, however, can be described relative to a fixed idea called a dimension.  A bead on a string can move along the string, but nowhere else, so it can move in one dimension.  A figure on a screen can move up and down or side to side on the screen, but it can’t reach out of the screen, because it can only operate in two dimensions. We can move up and down, side to side, and backwards and forwards, because we have three dimensions. But change as a concept makes no sense whatsoever aside from the context of time. This hypothesis postulates that the very context that makes sense of change is changing, but for that to make sense, it must change within a time-like dimension of its own. Thus, time actually experiences time! If we could travel between the versions of time and change them, the entire timeline of time would be changed, so we know that the time that time experiences also experiences time. How far does this go? Are there an infinite number of dimensions? Another way to put this is that the bead on the string can move on the string, but the entire string can move back and forth on a piece of paper.  The figure on the screen can only move on the screen, but the screen can move towards and away from you.  So you can move in space, and space moves in time.  So each successive dimension is like a time for the last dimension. So if space moves in time, what dimension does time move in?  That may be a little harder to grasp, but I feel like it gives a better understanding of what is going on.

This brings up an interesting theological question. If there are infinite dimensions, how many dimensions does God have?  Or does he have dimensions at all? Or maybe he has all the dimensions. I don’t have any answers for this, but I would love to talk about it in the comments.

Finally, the worldview concept I touched on briefly, about whether time’s time had a beginning actually can be used in a proof for the existence of God, which I will be posting soon, so consider this a teaser for that.

Anyway, I hope this made sense. I started it several months ago and heavily edited it, but seeing how much I found to edit, there are probably still lots of errors.