In 1915 Albert Einstein has calculated in his general theory of relativity that there is another dimension to space, I call it the 5th dimension, because the 4th dimension according to Einstein is the time (for the very accurate here). Since the release of Einsteins theory it’s over with our beautiful three-dimensional world! Einstein started consistently from the proven fact that light has always and everywhere just the same speed and he has realigned the whole physics around the light. He found out that gravity is explained by the fact that our three-dimensional space is not uniform, but is curved in a higher, so fifth dimension. It was a theory at that time, today, the theory of relativity has been proven in many cases (I’m sorry it is german).

## 5. Dimension as a Fact

So, there is a fifth dimension in our universe! It is not an invention from a science fiction novel, it is not fantasy, it is a scientific truth, it is bare fact. I call it on this site, where it is about geometry, the 4th Dimension, because in geometry there is no time or it is not taken into account. Is a bit confusing: in the universe the 5th dimension, in geometry the 4th dimension.

## Words for the 4th /5th Dimension

But we have no words for the geometric fourth dimension. How should we describe something that we cannot imagine? As a geometric figure there is the square in the second dimension, the cube as equivalent in the third dimension. For the fourth dimension, we can then call the corresponding structure “hypercube”, from the Greek prefix hyper = “above” (Latin “super”). Thus, we can name things provisionally in the four-dimensional “hyperspace”. For the geometrical figure of the hypercube, and for some other geometric figures there are own names. But much remains unknown and simply indescribable.

## Imagination of the 4th/5th Dimension

How can we imagine a fourth dimension? Truth be told, not at all! Our brain, our ability to imagine is designed for three dimensions. We can design a four dimensional geometrical figure, can describe it, can calculate its surface, but we can not imagine it at all. The four-dimensional equivalent of a cube is, for example, the so-called “tesseract”.

This hypercube has 32 edges, 24 squares as surface and eight cube cells as three-dimensional limits of the four-dimensional hypervolume. We can project this hypercube in many different ways on a two-dimensional piece of paper. In the adjacent image you can recognize with some geometric imagination a yellow, a pink and a light blue cube, and with a lot of imagination you may count perhaps the remaining five cubes. But how these eight cubes should form a hypercube, you can not really imagine. Anyway I’m getting here a “node in the brain”. If it will be technically possible to draw 3-dimensional holograms into the space with a half-transparent substance, we could project the hypercube in the third dimension and show a 3-dimensional model of the tesseract. But still we can not imagine it.

Here, if you’re a fan of geometry, you can see graphicly some 4-dimensional figures in a video . And here (in german) the question whether there are perhaps still more than 4 dimensions.

## Nature of the 4 ./5. Dimension

And what about the nature of the fourth dimension? As well as the transition from the second to the third dimension creates new possibilities, new features, new complexity, of course also the fourth dimension is infinitely more complex and richer than our reality, indeed our entire universe. Our universe is related to the fourth dimension, as is the two-dimensional surface of a window related to a 3-dimensional house. The house has a lot more window areas than just this one, it has storeys, stairs, walls, ceilings, floors, furniture and much more. The 3-dimensional house contains numerous 2-dimensional “worlds”. And in addition it contains the 3-dimensional elements. Similarly, there can be many 3-dimensional universes in a 4-dimensional world. And if there are living creatures in a 4-dimensional world, who can move in four dimensions and perceive four-dimensionally, then we can no longer hide from them. We can pack ourselves in a bunker of several-meters-thick concrete or lead plates. A four-dimensional being can easily see us and find us, because we can not brick up the access from the fourth dimension. We firstly don’t even see the entrance from the fourth dimension, we don’t know where it is, and secondly, we have no material out of which to build a four-dimensional wall. Just as a two-dimensional stick figure on a surface cannot hide from us three-dimensional people, neither we can hide from four-dimensional beings. They see everything we do. They can grasp our entire world with a single glance, just as we can overlook a huge 2D area with a panoramic view from the helicopter.

So my conclusion is: If there is a gravity in our world, and if this gravity can only be explained by a fault in a higher dimension, then there must be a 5-dimensional world (with 4 spatial dimensions and 1 time dimension) even if we don’t see it or cann’t experience it. And if there are living creatures in this 5-dimensional world, then these 5-dimensional beings can see everything we humans do, we can not hide from them.

Read next quantum physics. If you’re one of the people, who feel sort of sick just by hearing the word “Mathematics” or “Physics”, you can also immediately continue reading beyond.

*[translation revised 08 Sept 2019]*