Transcription
Imagine that this folder is a dimensional plane. Now, assuming that it has no height and no depth, what would this mean? It would mean that it's a one-dimensional world.
So, if hypothetically an organism was living inside of it, it would only be able to move in a linear path, forward and backward, in a straight line.
Now, if we go to the second dimension, we have two dimensions: width and length. Hypothetically, if an organism lived inside of here, then it would be able to move up, down, left, right, and anywhere else in between.
A two-dimensional world is comprised of an infinite series of one-dimensional worlds stacked upon each other, just as our three-dimensional world, which has depth, length, and height, is comprised of an infinite series of two-dimensional worlds.
Now that I have stacked many folders upon each other, we have three dimensions: depth, length, and width.
What happens if you keep going from here? We would have a four-dimensional world. What exactly is a fourth dimension? In order to understand this, we need to understand how two dimensions are perceived.
We live in a three-dimensional world, but despite that, we actually view things to be two-dimensional. Take a perfect sphere, for example. If you're looking at a sphere, it looks just like a regular two-dimensional circle. The only way you could tell it's an actual sphere instead of a circle is because of the hues of light.
Just like in a two-dimensional world, if an organism in the two-dimensional world was looking upon a circle, the light would make it appear to be lighter at one end and darker in the middle. Also, if an object is moving closer and farther away from you, you don't actually perceive that it's getting closer and farther away. You see that it's becoming smaller or larger, and then you assume that's giving either farther away or closer.
But let's say that object was to grow in perfect equilibrium, so that it was growing at the same speed that it was shrinking as you move it farther away. Then you would not be able to tell, without any lights or details on the object, that it's moving or growing at all.
You may have assumed that since we perceive things to be in two dimensions, a two-dimensional organism would see in one dimension. So, as we're watching this rubber band expand as it moves farther away from this little organism in the two-dimensional world, it does not actually perceive anything is happening to it because it's growing at the same speed that it's moving farther away.
But since we can actually see it from the three-dimensional world and perceive things to be in two dimensions, we can see things for how they actually are. The reason that the two-dimensional organism doesn't see things the way they really are is because the two-dimensional organism sees things in one dimension, just how we three-dimensional creatures see things in two dimensions.
So, in a way, we don't really see our world the way it truly is. A four-dimensional creature, if ever seen in our three-dimensional world, would be able to see through things, to be able to see absolutely everything.
Just as we could see if there were several organisms spread along a 2D environment on your floor, you'd be able to see inside houses; you would be able to see inside of people.
So, if a two-dimensional world, the flat surface, is just made of an infinite amount of lines, then the 3D world is just made out of an infinite amount of planes.
The 4D world, logically, is made out of an infinite amount of 3D objects. Though they're not just put together like you would with building blocks, that's not how the 4D world is; that would just be 3D again.
In order to understand this, we need to understand the logical progression of mathematics in our world. Imagine that this connected piece represents the first dimension. It's simply a straight line, which is basically what the first dimension looks like.
If you add three more of these straight lines and connect them so that adjacent sides are perpendicular and opposite sides are parallel, then you have the basic shape of the second dimension: you have a square.
Now, if you keep going from here and you add four hands so that there's a total of four squares and all adjacent sides are perpendicular and all opposite sides are parallel, then you end up with, obviously, a cube.
If you try to keep going from here, you would have a four-dimensional basic shape: you would have eight, what's called a tesseract.
Now, I cannot show you a tesseract, but you need to understand that it's basically four cubes that are within each other, that have all adjacent sides perpendicular and all opposite sides parallel. Yet there are four lines connecting at each vertex.
So, every tesseract would look somewhat like this picture. Now, that's not exactly what it looks like because this is a two-dimensional depiction, and obviously, not all the lines are straight.
So, I cannot show you what a tesseract actually looks like because we cannot perceive things in the third dimension. You cannot even imagine what the tesseract looks like; you cannot physically, and you cannot in your mind picture the fourth dimension or a fourth-dimensional shape.
You can keep going on from the fourth dimension; you can go to the fifth dimension, the sixth dimension, the seventh dimension. It doesn't matter; theoretically, there are an infinite amount of spatial dimensions.
A common misconception of the fourth dimension is that the fourth dimension is time. Now, while some argue that by going forward and backward in time, if you move forward the same distance and backward the same, then you would end up in the same place you started, just like in the fourth dimension.
While that may seem logical, if you think about it, it really doesn't make sense to imply that the fourth dimension is actually time. Well, first of all, time is not spatial; there's a difference between space and time, quite obviously.
Assuming that all dimensions are according to a pattern, then that doesn't really make sense either. Because saying the fourth dimension is time, every dimension has time in it, so that would mean that the fourth dimension is special in some way, which doesn't really make any sense.
Another reason this doesn't make sense is that we very, very, very slightly travel through time whenever we move due to the distance that light takes to get to our body. If a group of astronauts were to get in a spaceship and they were to go very, very, very close to the speed of light, then they would, and they went around in this impossible, nearly the speed of light spaceship for a few months, and then afterwards they returned to Earth, they would find that Earth had actually progressed a few years.
So, they had moved forward in time by moving that quickly.
Another interesting concept involving the fourth dimension is that many physicists and even mathematicians may say that the dimensions are very, very slightly curved. Because if you really think about it, nothing can be truly absolutely infinite.
So, imagine that the first dimension, the line, is just very, very slightly curved so that after a very long time, it will end up creating a circle.
As suggested by many physicists, if you keep going in the same direction, then you will end up where you started after a very, very long amount of time, obviously.
The same thing would happen to the second dimension. If it's just a square and then you extend it very, very slightly and curve it, it will eventually make a sphere.
The same thing happens in our dimension, except it will form a very, very slightly curved third dimension, which will form a four-dimensional universe, basically.
So, what this kind of means is that our three-dimensional world is within a four-dimensional world, and the four-dimensional world is within the fifth-dimensional world, and so on.
Now, I did say that nothing can be truly infinite, but if this is true and a dimension is really within another dimension, within another dimension, within a dimension, then I'm implying that there's an infinite amount of dimensions, which is the only problem I really have with this theory.
I'm not sure if it ever stops or if infinity is really even possible. We don't know that.
Thanks for watching my video, and I hope this gives you a better idea of what the fourth dimension is.