The space of human life is a three-dimensional space, and all the objects in our world that can be observed by us can be expressed in three dimensions: length, width and height, and expressed in Cartesian coordinate system X, Y and Z. ..
Three-dimensional is what we usually call three-dimensional, or 3D. Then one dimension is a line without width, and the other dimension is a surface without height, which is not difficult to understand, although we can't observe one dimension and two dimensions (because it doesn't belong to our space, even if it exists, it can't be observed, and no thickness means it is transparent).
Spatial dimension is the most basic feature of geographical phenomena. According to the actual distribution characteristics of geographical objects and the needs of map expression. Including: 0 dimension, 1 dimension, 2 dimension, 2.5 dimension and 3 dimension.
There are two spatial dimensions. It may extend far and can be directly revealed; It may also be small, curly and hard to see. The water pipe is thick, and the size around the pipe is easy to see.
If the tube is thin, as thin as hair or capillary, it is not easy to see the curl size. On the smallest scale, scientists have also proved that the spatial structure of our universe has both extension and curl dimensions.
Extended data:
Multidimensional space There are more dimensions in understanding the space of the universe. Looking back at how relativity and quantum theory contradict each other, we can easily understand that these two theories cannot be unified in daily three-dimensional space, and their contradiction is inevitable, and they can only be unified in high-dimensional space.
When the universe is at such an extremely high temperature as 10 32K (26 times higher than the sun's temperature 10 26), gravity is separated from other forces, and gravity continues to extend into long-range force with the expansion of the universe. With the further expansion and cooling of the universe, the other three forces began to break, and the strong interaction force and weak power were separated.
When the universe formed 10-9 seconds, the temperature dropped to 10 15K, and the weak electric power was decomposed into electromagnetic force and weak interaction force. At this temperature, the four forces have separated from each other, and the universe has become a "soup" composed of free quarks, leptons and photons. Later, as the universe cooled further, quarks combined into protons and neutrons. They eventually form nuclei. Three minutes after the creation of the universe, stable nuclei began to form.
When the Big Bang happened 300,000 years later, the earliest atoms came out. When the temperature of the universe drops to 3000K, hydrogen atoms can be formed and will not be broken by collision. At this point, the universe has finally become transparent, and light can travel for several light years without being absorbed.
Today, 6,543.8+000 to 20 billion years after the Big Bang, the universe is surprisingly asymmetrical and fragmented, resulting in amazing differences among the four forces. The initial fireball temperature has cooled to 3K, which is close to absolute zero.
This is the evolutionary history of the universe. With the gradual cooling of the universe, the mutual entanglement will be released and gradually separated. First, the gravitational force explodes, then the strong interaction force, then the weak force, and finally only the electromagnetic force remains unchanged.
References:
Baidu encyclopedia-space dimension