In mathematics and physics, the concept of dimension provides the basis for our understanding of the nature of space and objects. The dimension of an object can be said to be the minimum number of coordinates of points required to describe the object. From one-dimensional lines, to two-dimensional planes, to three-dimensional solids, these dimensions are everywhere in our daily lives. But when we step into the fourth dimension, it will be a real adventure of thinking.
Imagine a line. Every point on a line segment can be represented by a coordinate, so it is of dimension one. To turn this line into a plane, we need two coordinates to describe each point. In three-dimensional space, objects like a cube or a sphere require three coordinates to determine their position. So, how many coordinates does a point need in four-dimensional space?
In four-dimensional space, imagine an object called a hypercube (or tesseract).
A hypercube is a difficult concept to imagine because it is beyond the scope of our everyday experience. Each face of a four-dimensional cube is a three-dimensional cube, and it itself has incredible properties in four-dimensional space. In our three-dimensional world, the perception of the fourth dimension is only from some kind of projection, which is like trying to present a three-dimensional cube on a two-dimensional plane, which will never be fully presented.
To understand the four-dimensional cube, it helps to use some metaphors. It's like putting a cube in front of a group of people, observing it from each person's perspective, and piecing together its complete appearance from the different sides they see. This is also the characteristic of four-dimensional space, because our perspective in three dimensions cannot fully capture the true form of four dimensions.
Scientists and mathematicians have tried in various ways to codify these complex concepts.
In physics and mathematics, we often use dimensions to describe the properties of space and time. For example, in classical physics, the three-dimensional space and one-dimensional time we are familiar with are often regarded as the basic combination, and this four-dimensional time-space lets us know that the occurrence of events depends not only on the spatial position, but also on the passage of time.
Furthermore, four-dimensional space is not just an abstract concept that exists in mathematics, it is closely related to our theory of the universe. From Einstein's theory of relativity to modern quantum mechanics, various theories have introduced more dimensions to describe the laws governing the operation of nature.
The concept of high-dimensional space makes it possible for us to study the universe and the laws of physical forces, while superstring theory requires the introduction of the concept of ten-dimensional space to unify the basic interactions.
Scientists further deduced that the basic properties of superstring theory need to be explained in higher-dimensional space, which makes us think about the diversity of dimensions and their importance in theoretical physics. For ordinary people, whether it is a three-dimensional solid model or a four-dimensional hypercube, it is an opportunity to guide us to think about deeper issues.
The application of high-dimensional space is not limited to physics. There are also many abstract categories in mathematics that introduce the concept of dimension. Extending to higher dimensions can provide people with a new perspective to understand complex systems. For example, in data science and statistics, as the dimension increases, the structure and behavior of the data become increasingly difficult to grasp. This phenomenon is called the "curse of dimensionality", and it is ubiquitous in data analysis.
How do dimensions shape the way we understand the universe and data? Is it possible to find some practical meaning in these abstract graphics and concepts?
Exploring these questions not only advances our scientific knowledge, but also inspires endless creativity. Ultimately, through exploration of dimensions, we can begin to understand more complex phenomena and how they intertwine with our daily lives. Have you ever wondered how to find the meaning of your own existence in the concept of a four-dimensional cube?