The ultimate In all travel, right? Who wouldn't want the experience? But what exactly is it? When you travel through space, what exactly are you traveling through?
This is a subject I had read a little bit about when reading through some quantum physics books a few years back. I hadn't thought much about it lately until one of the engineers I worked with in my last life sent me a text after reading my Time Travel post here:
I sent this post to a couple engineers I used to work with because I was interested in their comments. I know they are smarter than I am so I'm always interested in different perspectives. Engineer R3 didn't disappoint and sent me this text:
"In the very place that incremental space-time is created, is it totally devoid of entropy? I say YES"
Well, I hadn't really considered that in my post. Didn't even see the relevancy of it at first, but then I realized it's quite relevant. That's why I appreciate the comments, because I know others have a better perspective on this than I do.
What is the relevancy of entropy in space-time? Well, remember that entropy is a measure of the disorder of things. So if you are to adhere to the belief that R3 is suggesting, then you would have to believe that newly created space-time is void of any type of structure. In other words, the new empty space is truly empty.
So that begs the question what is empty space? When we travel through space, what are we traveling through?
Well outer space is not truly empty because gravitational waves and electromagnetic waves are constantly permeating space. It is these gravitational waves that actually warp space as Einstein proved. But that doesn't mean the gravitational waves and electromagnetic waves make up space, they simply travel through space and influence it, but what are they traveling through and influencing?
What I'm really asking here is what is the fabric of space? What is the canvas background that our world and our universe is painted on? If we believe that entropy does not exist in space-time, we believe space-time has no fabric, because it has nothing of order to "flow" to disorder.
Furthermore, if you believe the consensus of most physicists, in that the direction of time is determined by increased entropy, then you would have to believe that time doesn't exist in empty space where entropy doesn't exist. But personally, I don't adhere to that belief. I think it's possible that space could be truly empty and void of entropy and time can still exist in space. In fact it does because space-time is inseparable.
The reason I do not believe that entropy sets the direction of time is because entropy isn't always increasing. In fact, in our local world, entropy decreases much of the time. Every time we build a building of structure, we construct a low entropy state. Every time a baby is born, this newborn baby is begat in a low entropy state. Of course the overall entropy of the universe is constantly increasing but locally you can decrease it. So if we can locally decrease entropy, it's not like we're slowing down time or anything locally. In our locality, time continues to move at the same pace regardless of the local entropic condition (gravitational and relative motion being constant of course). That's the main reason I can't adhere to this theory. And that's what it is a theory, because there's no math or experimentation to back it up.
Go back now to what R3 suggests. I believe the suggestion implies, or at least I infer from it, time can exist, and does exist in empty space, even if it's void of structure and entropy. And if spacetime is truly void of structure, meaning there is no fabric upon which the worlds are hung, then what exactly are we traveling through when we travel through space? Truly nothing?
After further thought on space void of entropy, and therefore "fabric", for lack of a better word, I believe there has to be some substance to space-time. If not, then what exactly is gravity influencing when it warps both space and time? Doesn't that mean space is not truly empty? But I'm certainly not adamant in my opinion on this matter. I've learned the more I learn, the more I realize my ignorance. It could be space-time is nothing more than a geometric configuration, void of substance, and R3 is correct.
What exactly is empty space is a question that still seeks an answer. There are many theories available out there. Just pick one or make up your own! I've read a number of these theories with glazed eyes. Since we can't actually see empty space or measure it (other than the geometric structure gravity influences), it all comes down to philosophy or theory.
If you think you know the answer, I will refer you to one of the most prominent physicist who ever lived, Richard Feynman's famous quote:
“I think I can safely say that nobody understands quantum mechanics.”
So if you're reading this and don't understand my ramblings, don't worry, nobody understands this stuff! I certainly don't!
If anyone reading this becomes a future (or past) space traveler, please comment below on your experience. I'm curious what you travelled through. 😀