4th dimension

A four dimensional space (4D) commonly known as space-time to the scientists is a mathematical extension of the concept of three-dimension or 3D-space. To understand 4D we need to first understand dimensions. So, dimension is a measurable extent of a particular kind or in simple terms dimensions are direction. Firstly, there is zero dimension which is just a point in the universe. It has no length; breadth or height it is just an infinitely small point.

The above picture shows 0^th dimension.

 

Then 1^st dimension, it’s a line with just length and no breadth. If you connect 2 zero dimension the you get the first dimension or 1D and if we were to live in the 1D world, we could only see in zeroth dimension or we could only see points.

The above picture shows 1^st dimension.

 

Similarly, 2D or 2^nd dimension or square is created by combining 2 1D lines. If we are in second dimension we can see the world in first or zero dimension we can just see straight and back. There is actually a term for hypothetical beings of 2^nd dimensional beings, “Flatlanders”.

The above picture shows 2^nd dimension.

Now, third dimension it is the world where we live the is length, breadth and height it is created by join 2 2^nd dimension. We can even call 3D a cube. We are actually living in a 3d world. In the 3^rd dimension we can see in both 1d and 2d meaning we can see left, right, forward, backward, up and down.

The above picture shows the 3^rd dimension.

 

A four-dimensional space (4D) is a mathematical extension of the concept of three-dimensional or 3D space. Three-dimensional space is the simplest possible abstraction of the observation that one only needs three numbers, called dimensions, to describe the sizes or locations of objects in the everyday world. For example, the volume of a rectangular box is found by measuring and multiplying its length, width, and height (often labeled x, y, and z).

 

Similarly, the fourth dimension is the dimension created by joining 2 3d or by joining 2 cubes the 4^th dimension is known by many names such as tesseract, hyper-cube, space-time, the time dimension etc. many scientists believe time is the fourth dimension however all the things that we know about 4d is theoretical or hypothetical. Nothing is actually proved about the 4^th dimension. But the string theory, m-theory, many worlds interpretation suggests that there are many spatial dimension.

The idea of adding a fourth dimension began with Jean le Rond d'Alembert's "Dimensions" published in 1754 was followed by Joseph-Louis Lagrange in the mid-1700s, and culminated in a precise formalization of the concept in 1854 by Bernhard Riemann. In 1880, Charles Howard Hinton popularized these insights in an essay titled "What is the Fourth Dimension?", which explained the concept of a "four-dimensional cube" with a step-by-step generalization of the properties of lines, squares, and cubes. The simplest form of Hinton's method is to draw two ordinary 3D cubes in 2D space, one encompassing the other, separated by an "unseen" distance, and then draw lines between their equivalent vertices. This can be seen in the accompanying animation whenever it shows a smaller inner cube inside a larger outer cube. The eight lines connecting the vertices of the two cubes in this case represent a single direction in the "unseen" fourth dimension.

The above image shows 4^th dimension.