Dark Matter, Part 2. The nature of time.

Here's Part 1

Now, here is another concept relevant to this broader discussion. It may be familiar to some of (the two of) you, but here goes. We are used to thinking of time as its own thing. We even split it off from space to reference space-time or spacetime. The problem is, time is not separate but related. Time is a dimension, the 4th dimension. Time is the fourth dimension of space, not a separate-but-related thing. To whit:

• The first dimension is length. It goes in two directions. For this discussion, left and right.
• The second dimension is depth. It goes in two directions. Toward and away.
• The third dimension is height. It goes in two directions. Up and down.
• The fourth dimension is time. It goes in two directions. Forward and backward.

Edit: This incredible video explains this fairly well. Rob Bryanton is apparently a genius, and while I first saw his "Imagining The Tenth Dimension" video  quite a long time ago, I just discovered this video (and his channel--omg am I going to spend a lot of time there) while adding links to this already-written post. I feel kind of like an idiot. Well, not the first time, and certainly not the last. 

See, this is the thing that has taken me thirty years to finally understand. Sue me, I'm a slow learner. Measuring velocity, for example, can be stated as "miles per hour." What is really measured, though, is simply the shift in spatial location. That's it. Since time is only a dimension of normal space, stating "88 miles an hour" is actually describing a simple locational shift. At 88 mph, you will go this far along the x, y, z axes AS WELL AS along the axis of time (for which I will snag the variable q for this discussion). Without the axis of time, you would instantly teleport from one place to another—you would simply blip 88 miles (or whatever), without traveling along any of the axes of space. To borrow an explanation, you would simply jump over the intervening distance to instantly arrive at that particular location. The inclusion of time as another measure of space is the only way to allow travel—actual movement—along the other 3 axes as well. *

Something else to consider: even if something does not move along the x, y or z axes, it still moves along the q axis unless its existence is literally instantaneous. To be fair, it is unlikely that there are many things in the universe that are not moving at all, but things that are not moving in relation to one another are an accessible example. The stupid thermometer that doesn't work out on my front porch, for example. It doesn't move (x, y, z) in relation to the porch, the house, the street or the town, but it, as well as the other things not moving x, y, z, are still moving along q together. Anyway, side note.

Everything in our experience, everything in our existence, has been continually moving in one direction along q. We are continually, constantly moving forward through time. Effect follows cause. Consequence succeeds action. Just like, if you drop something, it falls down, so too do we continually "fall" forward through time. If gravity pulls down, then what is the mechanism for this direction of travel along time? I have suspicions, but only that, so I won’t go into it here. The point is that we move in one direction through time, but as a dimension, time has two directions. This is the entire principle behind the idea of time travel, after all, either speeding up travel forward or allowing travel backward.

Next up, part 3, where I try to bring it together.

* The Time Machine (1960) had a fair explanation of the concept of time as a dimension. It was still a bit thin, and the movie itself is pretty awful, but it tried to explain the idea that time is a measure of space more directly than Doc Brown did. It also explains a couple interesting homages/easter eggs in the Back to the Future movies, but I digress.