What is a Tesseract? – Understanding the Fourth Dimension!

A zero-dimensional space is just a point with no size, length, width, or height. It’s the simplest form of a location. When we move to one-dimensional space, we have only length with no width or height, which we can think of as a straight line. If an organism lived in a 1D world, it could only move forward or backward along that line. This 1D world is made up of an infinite series of 0-D points stacked in a line.

In a two-dimensional space, we add width to the length, creating a plane like a flat sheet of paper. Theoretically, an organism in a 2D world could move forward, backward, left, or right. A 2D world consists of an infinite series of 1D lines stacked to create a plane.

The three-dimensional worlds has length, breadth and height. As a two-dimensional world is comprised of an infinite series of one-dimensional worlds, the three-dimensional world is comprised of an infinite series of two-dimensional worlds.

Humans live in a 3D world with length, width, and height. But our eyes only capture a 2D image of this 3D world on our retinas, like how a camera takes a 2D photo of a 3D scene. Similarly, a 2D organism would see only a 1D view of its world, unable to fully perceive things around it. Just like the 2D creature can’t see its world completely, we can’t see the full 3D nature of the objects around us.

If organisms existed in the four-dimensional world, they could perceive things around them in 3D. A four-dimensional organism can see through houses, buildings and everything just as we could see if there were several organisms spread along a 2d environment on your floor, you will be able to see inside houses you would be able to see inside people. So the four-dimensional world can be taken as being comprised of an infinite series of three-dimensional worlds.

A line represents the first dimension. If you connect four lines at right angles, you get a square, which is the second dimension. Moving to the third dimension, connecting six squares forms a cube. In the fourth dimension, you have a tesseract, which is made of four cubes stacked together. Thus, the 4D world consists of an infinite number of 3D objects. The problem is that you can’t see a tesseract and it's far beyond human imagination. But we could visualize it in 2D like how we visualise a Cube. This will not be an exact representation because you are seeing a 4D object in 2D.

You can keep going from the fourth dimension even to the fifth dimension, the sixth dimension, the thousandth dimension. It doesn't matter; theoretically, there are an infinite amount of dimensions.

Popularly, the fourth dimension is portrayed as the dimension of time. This aligns with the scientific understanding of time as the fourth dimension, perpendicular to the three spatial dimensions we experience. It is depicted that time as a physical construct can be navigated and manipulated, with characters able to move through time and witness events from the past, present, and future.

The fifth dimension is commonly depicted as a realm where the traditional laws of physics, including the usual constraints of time and space, do not apply. It is portrayed as a higher-order dimension that transcends the normal three spatial dimensions and the fourth dimension of time. The fifth dimension is associated with gravity and the fabric of spacetime itself.

Geometrically, we live in a 3D world with length, width, and height. But scientifically, Einstein’s theory of general relativity says we actually live in a 4D space-time where the fourth dimension is time, where gravity is seen as the curvature of this space-time caused by mass and energy. Kaluza-Klein theory extends this by adding a fifth dimension to unify gravity with electromagnetism, with this extra dimension being compactified (too small for us to see).

* Do you know that according to string theory, there are typically 10 or 11 total dimensions.