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?

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Some More Thoughts on Relativity

I admit it, I’m a terrible blogger. At least I am when life happens. Which it kind of always does. Otherwise, I, you know, wouldn’t have one. But if I can’t keep up with a consistent posting schedule, the least I can do is follow up on a promised post. Unfortunately I haven’t done any of the math-work on the promised Special Relativity post (I’ve had enough school to do without calculating a new definition of motion), but I can update you on my discoveries about General Relativity.

As I mentioned in my last post (over two months ago…), I had a chance to talk to Korean physicist Min Seong Lee about my ideas on relativity, and what he had to say enlightened me in a few ways, both positive and negative.

First, it turns out that the problem I found in relativity is actually only a problem in the oversimplification of the theory that is used to explain it to high schoolers. To recap, my problem with the theory was that a simple warp in space time would cause particles to curve in observed space, but not at all in the way we see gravity behaving, and it would never accelerate a particle from a stationary position relative to the space-time. To solve this problem, I proposed that instead of mass warping space-time, space-time moves towards mass. What Min Seong pointed out to me is that, while a particle may be stationary relative to the three dimensions of space, no particle is ever stationary relative to time. Time is always flowing, providing the moving dimension that I proposed was necessary to create motion within space. I am still not sure entirely how this works, even though he showed me an equation that demonstrated how moving time acceleration (or if I did, I have forgotten my understanding in the months it has taken me to get this written down).

Now, the happy part of this is that, because of the moving time aspect and some of the math involved, my idea is basically just another way to say what already existed in the theory, so while I wasn’t the first to come up with this idea (though maybe the first to state it the way I did), my idea was, in fact, correct (or at least mostly so). While I may be merely following in the footsteps of minds greater than mine, it is still exciting to follow their footsteps with my own mind, rather than getting pushed along the path in a stroller. Textbooks are great for learning things, and I would never have been able to discover what I have without the foundation they gave me, but there is nothing like discovering cool science stuff for yourself.