### Beyond the Third Dimension Fourth Dimension: Tetracube

The 'we can perceive' is the dimension in which we are located. Our visual intelligence and brain are shaped according to 3 dimensions. We do not have the opportunity to perceive the fourth dimension “yet”.
According to our knowledge of physics today, the 'dimension' is considered as the fourth dimension, which we all know, which gains more importance with Einstein's theorems. That is, we exist in three physical dimensions and time dimensions.

It is believed that the fourth "physical" dimension other than the time dimension was first derived by Charles Howard Hinton in 1888. Scientists have called this four-dimensional structure a tesseract (Greek tesseres actress = four rays) or tetraküp and tried to bring it to the size we perceive visually.
Tesseract is a 4-dimensional cube. Theoretically, it is the name that has a four-degree earring with an angle of 90 degrees between all its edges, all edges and surface areas of which are equal, four edges perpendicular to each other.
In fact, if we want the existence of a fourth dimension, we can explain mathematically using any of the concepts of relativity theory, parallel universe, black hole, velocity of light, or all of space. But our current aim is not a mathematical explanation or proof methods.

When you look at the animation below, it can be seen that 2 cubes pass through each other. But the square surfaces you see do not actually bend, stretch and shorten in a 4-dimensional universe. The shrinkage and deformation here is an imperative made to visualize these four dimensions in our three-dimensional world. When you examine a little more carefully, you may notice the 4th Dimension. It doesn't matter if you haven't noticed because the human brain is not designed for it. Here, a little bit of abstraction and perspective come into play.
In order to understand better, it is necessary to enter the concepts in a little detail:

Size: is the term geometry used to express a size measured in a particular direction. In physics and mathematics; The size of a space or object is unofficially defined as the minimum number of coordinates required to determine any point on this space and object.

Let's consider this; The smallest structure that we can draw with a pencil on the paper we receive is “dot”. The point is considered to be zero-dimensional or non-dimensional. If we draw two different points and connect them, we will get a line. The line is 1-dimensional because it contains only length. By making two lines on the paper and connecting them at the end points again, we get a square or rectangle, which is 2-dimensional because it contains an aspect. In the same way, if we draw two squares on the paper and connect them from the corner points, we get a cube. Our cube is 3 dimensional as it contains width, length and depth.
0th dimension: dot • 1st dimension: 2 dots = line • 2nd dimension: 2 lines = area • 3rd dimension: 2 fields = space • 4th dimension: 2 spaces = time.

If we want to obtain a geometric object of any size, if we make 2 copies and connect them at the geometric ends, we can combine it: we can produce a dimension out of nothing.

For example, as we see in the above figure, if we want to get a tesseract (tetraküp), it will be enough to combine 2 copies of the cube from the corners. In Tesseract, 8 cubes consist of 24 squares, 32 edges and 16 corners.

Physics and math always borrow information from each other. Sometimes mathematicians develop, use physicists, sometimes physicists discover and develop mathematicians. When the higher dimensions geometry first began to be studied in the 1800s, it was generally considered purely mathematical. However, the development of modern physics in the early 1900s; With relativity and Super String Theory, the emergence of Einstein's theories, an idea taken seriously by physicists has been a tool for us to understand the universe.

The fourth dimension we obtain with mathematics is considered as the time dimension in today's Einstein-based physics. The visual expression we make here consists of a simulation, a mental gymnastic, in order to understand the “time” dimension visually.

In theories that try to explain more micro areas such as string theory, we see that more dimensions are being added (perhaps compelled) to the universe. So much so that Super Space Theory, M Theory and Bozonsal String Theory claims that physical space is 10, 11 or 26 dimensions.