I love to think about space and time. I find them fascinating. However, I’m not a cosmologist, so I don’t come at the subject with equations and theories. I just think and ponder. It’s more fun that way (for me, at least). If you don’t think they’re interesting, I’m sorry. Let me assure you though that more fiction will be up tomorrow.
We rarely think about space since it is such a fundamental part of our reality (in this post I mean “space” to be the area in which we move, not outer space). However, if you think about it, the idea of space is meaningless without matter. After all, when we measure distance, it is only defined as the amount of space between two pieces of matter. In math, a defined length is between two points. A ray, with one defined point, cannot have a defined length, since one end goes on forever, but we can still start measuring it, because we can start at the defined point. But what if you had a line with no defined points at all? The idea of distance would be meaningless. It could be the length of an atom or a galaxy. There would be no way to know.
Think of it another way: Imagine that nothing exists in the universe except a single photon, a particle of light. We know the speed that light travels in a vacuum, so we know that the light has to be traveling at 299 792 458 m/s. However, with no matter to define its progress, the movement of the photon is meaningless. It could speed up or slow down but to an observer outside the universe (if such a thing were possible) it would look as if it were not moving at all, regardless of its speed.
Time is very interesting to me too. An interesting thing is that while we use time to measure the speed of matter and energy, we can never measure the speed of time itself. That is because speed can only be measured relative to something else and we have no alternative to time.
Imagine that you are on a spaceship with no windows. There is no way of knowing how fast you are going (without instruments) or even of knowing if you are moving at all. Even if there were windows, but no planets or stars nearby, it would be impossible to tell. Speed can only be measured relative to something else.
From the point of view of an outside observer of the universe, the speed of time could fluctuate or even stop and we would never know. If this seems hard to understand, think of it like reading a book. For a fast reader, the story progresses quicker, but for a slow reader, it goes slowly. However, for the characters in the story, time goes exactly the same pace. You can even put the book down and pick it up a year later and the characters will never know the difference. The story only stops relative to the reader, something that the characters have no access to.
Another interesting implication of time is that it is only made meaningful by energy, which is manifested by movement through space. Imagine the entire universe with just matter but no energy. It would be frozen, dead, unmoving. Time would exist, but it would make no difference, since without energy, nothing would change and so regardless of how much time passed, everything would look the same. Without energy, a world with time passing and one without time passing would look exactly the same to an outside observer, just like the live video feed of a rock will look exactly like a picture of a rock, since neither one will move.
Do you understand what I’m getting at? Totally confused? Got a headache? Think I’m totally off base? Let me know in the comments. I like discussing these kinds of things.