The world we live in is a four-dimensional space-time and needs no popular explanation. Note that I said four-dimensional space-time, not four-dimensional space.
Our space is a three-dimensional space, that is, there are three dimensions: up, down, left, right, front and back. In mathematical language, it is the three dimensions of length, width and height, plus a one-dimensional time axis, which is called four-dimensional time and space.
This is the Minkowski space on which Einstein's special theory of relativity is based.
It is defined as: let V be a four-dimensional space on the real number field. If G is nondegenerate symmetric and its positive inertia index is equal to 3, then (V, G) is called Minkowski space.
On an appropriate basis, g has the following matrix:
The orthogonal transformation on V is called Lorentz transformation, the isotropic vector in V is called light vector, the vector X suitable for G (x, x) > 0 in V is called space vector, and the vector suitable for G (x, x) > 0 is called time vector. These related nouns point out the physical origin of Minkowski space.
This is the real space in which we live.
There is no other space in our world? Popular? , can only be described in mathematical language. Zero dimension is a point without length, width and height, so it is generally called singularity. But when we express it, we often point a point on the paper with a pen, which is zero dimension.
But this zero dimension is actually long, wide and high, and belongs to our world. In the four-dimensional space-time of the three-dimensional world, we can only see three-dimensional things, and other dimensions can be described, but we can't get them out.
One dimension is a line, which still has no width and height, but only length. You can also draw a line on paper and call it one-dimensional, but this one-dimensional has both height and width under the microscope.
Two-dimensional is a plane, with length and width and no thickness. Some people compare a piece of paper to a two-dimensional plane, but paper has thickness. The thickness of A4 paper is 0. 125mm (125mm), and 100 A4 paper is1.25cm. Even the thinnest paper has a thickness, so do atoms.
Three dimensions are our world.
Do zero-,one-and two-dimensional spaces exist? What if there is? Some people say that if there is life in that space, how can life be described? The picture above is a two-dimensional creature described by someone, but just for fun. It's all bullshit
Four-dimensional spacetime creatures have only four-dimensional spacetime brains and imaginations, and all imaginations are based on our long-term evolved thinking and concepts. How do we describe things in other spaces?
Four-dimensional space and five-dimensional space are both high-dimensional spaces. The mathematical explanation is that the four-dimensional space is a standard Euclidean space, which is a spatial dimension with the same properties as X, Y and Z on the basis of the real world of three-dimensional space.
There are different opinions on how to add this latitude. Some people say it looks like a Mobius belt, others say it looks like a Klein bottle. These are the projections of four-dimensional space in three-dimensional space.
Some people describe that any high-dimensional space is the superposition of countless low-dimensional spaces. One-dimensional space is the result of superposition of countless zero-dimensional spaces, two-dimensional space is the result of superposition of countless one-dimensional spaces, three-dimensional space is the result of superposition of countless two-dimensional spaces, and four-dimensional space is the result of superposition of countless three-dimensional spaces.
Then, the low-dimensional space is the projection of the high-dimensional space. As mentioned earlier, Mobius ring and Klein bottle are the projections of four-dimensional space in our three-dimensional space.
Since it is a projection, aren't we people, pigs, dogs, mountains, lakes, seas, the sun, the moon and the stars all phenomena in the three-dimensional world? Are they all projections of four-dimensional space?
Then the two-dimensional space is the projection of the three-dimensional world. You make your hand into a rabbit and throw it on the wall under the lamp. It is a two-dimensional shadow and a three-dimensional projection.
Therefore, some people think that in the four-dimensional space, creatures can travel at any time, 60-year-olds can go back to their thirties and their childhood, and childhood can also travel to old age to see.
In that world, you can see the deepest level of everything, and everything has no secrets.
Others describe the four-dimensional space as the animation above.
Liu's "Three-body/Death and Eternal Life" and interstellar movies both describe the state of people entering four-dimensional space, and interested friends can go and see it.
In fact, these are all human imaginations and cannot be taken seriously. These are all set by the inherent thinking mode of human beings living in three-dimensional space and four-dimensional space-time. If there is such a space, where all the physical laws or scientific theories are completely beyond our understanding, and all our scientific theories are invalid there, how can we explain what the state is there?
There must be laws and theories of hyperspace to explain it. If there is hyperspace, we can't know, let alone explain it in a popular way.
Space-time communication thinks this is a very popular explanation.
Conclusion: We can't understand hyperspace state except our own world, let alone describe it accurately.
Thank you for reading and welcome to discuss.
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