How many dimensions are there? What does each dimension mean?

"The space around us has 3 dimensions (up, down, around)." We can move up and down, and the other direction of movement only 3 three-dimensional axis of space to express. The downward shift is equal to the negative direction of the move upward, to the northwest is just a mixture of moving westward and northward.

In physics, Time is the fourth dimension, unlike three dimensions, it is only one, and it can only move forward.

We live in a space of four dimensions (3 axes and a timeline), based on Einstein's concept of four-dimensional space, our universe is composed of time and space, and this timeline is a virtual value axis.

Some theories predict that the universe we inhabit actually has more dimensions (usually 10,11 or 26). But these additional dimensions measure the size of the subatomic universe. (See string theory)

Dimensions are theoretical models, which are more pronounced in non-classical physics. So don't worry about the dimensions of the universe, as long as it is convenient to describe the line. ”

--from Baidu Encyclopedia

When we talk about space, our world is three-dimensional. When we talk about space-time, our world is 3+1 dimension, that is, 1-dimensional time and 3-dimensional space. So the theory of pillow water is not correct, our world is three-dimensional space four dimensions. Time and space are two concepts.

Let's talk about space first.

0-dimensional space, that is, a point without volume, is a mathematical concept, generally believed that the universe before the Big Bang is such a singular point, where there is nothing, in the words of big Liu is "absolute death." But according to the Big Bang theory to guess, the singularity contains everything, is the origin of all, is the magic of nothing.

1-dimensional space is a line, assuming that there are 1-dimensional creatures--although we do not understand how this organism exists, if there are--they will be only of a length without width, i.e. a point or a line. In the eyes of 1-dimensional creatures, they are creatures that live in a pipe without width, the world is a point, because there is no upper and lower around only before and after, so 1-dimensional creatures with no gap, it itself is a point, can not be smaller, so can only move forward, unless it is the power to promote the whole universe in order to move backwards. If, like our universe, the world is finite, it is a ring.

2-dimensional space, is a face, in the eyes of 2-dimensional creatures, there are only a variety of lines, such as a square, in the eyes of a 2-dimensional creature is a line segment, need to walk around it, to measure the length and angle of each segment, and then speculate on its shape and size, to come to a conclusion. But that conclusion is necessarily not what we think, so intuitive squares, because they never see the whole picture, they should be described as "this is a four length of XX side, each side angle between 90 degrees" object, we can name it as 4*90 shape. And more complex objects, such as a group of pupils of unknown meaning of graffiti, in their view, they need very advanced knowledge to measure, like we pinch a riddled mud regiment and then seek surface area. If, like our universe, the world is finite, it is the surface of a sphere (note, not a sphere!). , similar to the surface of the Earth, it is difficult to describe the shape, which in our view is a ball, but the spread of 2-dimensional organisms can understand, but what is that shape? Nothing, or how we cut it, what shape it is.

3-dimensional space, our universe, is a container of many stars and other matter in our eyes. Three-dimensional organisms and matter are made up of three of long and wide heights, in our eyes, all objects are two-dimensional plane, for example, we look at a cube dice, can only see three of them, our eyes and light to match so that we can distinguish the depth of three sides of the shadow, resulting in 3-dimensional feeling, but just feel, Rather than really three-dimensional, because we can never see all the faces of a dice, also can not see the contents of a closed container-just like we look at a two-dimensional circle, you can see at the same time it's up and down, the circle with a triangle, we also see, You can even hand out the triangle without destroying the shape of the circle. But the two-dimensional creature cannot see the inside of the circle directly, and must break the circle to get the triangle inside. Similarly, we want to take out a basketball egg, must break the basketball. If our universe is finite, it is a hyper-sphere, or we cannot describe it as round--because in our eyes it has no margin and nature cannot describe the shape. But we can use the mathematical inference that the universe is a ball, a ship starting at a certain point, sailing in a straight line, eventually crossing the nonexistent side, appearing from the other end, and then returning to the origin.

Diagram：

4-dimensional space--speaking here, we should be able to understand four dimensional space: the four-dimensional space of biology and matter is made up of the long and the high and a direction in our world does not exist, as we can from the 2-dimensional world does not exist in the direction, that is, high, to see the 2-dimensional world, and 2-dimensional creatures must rely on mathematics to do a glimpse of the whole picture, the naked eye can not see. The world in the eyes of four-dimensional organisms is three-dimensionally, and they can be in a three-dimensional direction that does not exist, and at the same time see all six faces of a square, and remove from that direction the objects in the object without destroying the seal of the object, and see the interior of the object.

It's already a God for us-four-dimensional creatures can easily take eggs out of basketball, take out the heart from the human body, and the basketball and the human appearance are not damaged; four-dimensional creatures can see the way we dress, the way we look, the muscles underneath our skin, the blood bone marrow of our blood vessels ... All our details are spread out in the eyes of four-dimensional organisms. As for the two-dimensional world, countless two-dimensional plane also stacked not three-dimensional objects, our details expand to let barb, for the four-dimensional life is so much, our "infinite" for the high dimensional life, is "limited."

Another example of being abused, we waved and cast a shadow of a hand in the two-dimensional world, a two-dimensional plane, and the four-dimensional creature waved and cast a solid shadow in our world. Our hands cross the two-dimensional plane vertically, in their world, there are five approximately round, real objects, and then gradually synthesize a flat object; The hand of the four-dimensional creature crosses our world in the fourth direction, that is, one or more irregular or regular objects appear in a vacuum, shape and volume constantly changing, Finally vanished into thin air. If, like our universe, the world is finite, it is a ... We can not understand, completely can not describe the appearance, let's call a cock burst super ball!

In summary, that is to say, only a higher dimensional creature can understand the whole world than its first dimension, but to their own dimension, we can only body in this mountain, see not clear face, fortunately there is mathematics, even if not clear, can also use the formula to see.

5-dimensional space and after the unknown number of dimensional space, I will not say, can only say that the direction of the increase in order, infinitely broad free world, and do not have the ability to describe them.

After saying "infinity," we Say "eternity." It's time to burn your brain!

1. First, time and space are different, we are three-dimensional biology, but only a little bit of material in the three-dimensional world, "I" is not the whole world. But the concept of time, but not so, "I" Material can become "you" material, but "I" time can never become "you" time, time is absolutely independent, cannot borrow, cannot seize.

2. As the 1-dimensional creature mentioned above, unless there is a power to propel the whole universe, otherwise can not retreat, so I think 1-dimensional time organisms, that is, we are also temporarily unable to turn back the time, it is not discussed, but more than 2-dimensional is possible, but this is beyond my ability, so also do not seriously discuss the issue of time reversal. And seeing the inference behind me, I can tell that there's no time reversal for 2-D-time creatures.

Based on these two points, I make the following inference:

0-D Time: Time is a point, that is, "none", where things will not change, everything is the most initial appearance, or even "initial" does not exist, because there is no end and no initial. If the Big Bang Theory is established, then 0-dimensional time can not discuss space, because 0-dimensional time is the eternal solemn and quiet, where there is no sense of space, which means that space since the Big Bang after the formation, with this "after", there is time, so 0-dimensional time can only exist in 0-dimensional space.

1-D Time: That is, the time of our world, the shape of the understanding is linear, but also can not be fully understood by the shape, because time can only forward can not retreat, and 1-dimensional space can move forward can also be backward. Time is a relative concept, things change, then time goes by, things do not change, then for this thing, time does not exist, but things exist in the cosmic environment, and the environment is changing, so it is impossible not to change, even if the environment changes, can also do a reference frame, and then get the concept of time.

In short, our time is a river, surging forward, not backward, no tributaries, we are the fish in the river.

"Death" means the end for us creatures, but for the rubble of stone, they will be accompanied by a point of time until the time disappears, in other words, we are in fact eternal. But the time after the decomposition is meaningless to our biology, so the creatures discussed below are also used by us as humans.

2-D Time: Time is a plane, with just the analogy, that is, 2-D time is a river with countless tributaries, in every moment is divided into unlimited possibilities, and 2-dimensional time in the world of life itself is a timeline, that is, a connected universe was born, one connected to the cosmic death (1-dimensional time biological time is a point , so we appear at some point in the history of the universe, and the two-dimensional creature is a line, which means that the universe appears when it appears, until the universe is over. They are in a similar "Nirvana" state, both alive and dead, both as children and as old people, who from the beginning have a complete and eternal life online, but in the horizontal, their time is still limited. All they have to do is move horizontally across a few tributaries, choose the best life for them, choose one, then lose the one. In other words, the existence of 2-D time organisms, is in countless "life" constantly looking for the best one, they do not need to swim along the river, but in life and death, the pursuit of "perfect life", the time spent in the horizontal movement, until finally ushered in the horizontal time of consumption completed, Fixed to a time line can no longer move, for them, this is equivalent to death. But for us, this is still the eternal with the universe.

3-D Time: If a one-dimensional time organism is a fish in a river, a two-dimensional time organism is a river of constant change, three-dimensional time life is greater (I think it must be described as great). They have a face-like time and move to form three-dimensional time. That is, they appear together with the universe and exist on all timelines, and they do not have to choose a timeline because they are born with all the possibilities. So, when we communicate with high time-dimensional creatures, they tell us directly what we are going to be, that is, 3-dimensional time organisms, and 2-dimensional time organisms need to be found to tell us, but 3-D-time creatures know "everything is possible."

So what is the meaning of the three-dimensional time organism? They are born across countless universes, already have all the possible experience, then the third vertical timeline, what will change? This question is beyond my imagination, and I can only vaguely speculate that since they have mastered all the parallel universes, the vision should begin to go beyond the universe, where they have the freedom they need. As for what they would do ... Who knows?

Wrote three hours, after writing quite feeling. We can never imagine the pursuit of eternal, eternal life, the pursuit of perfection, eternal and perfect creatures. Just like 2-dimensional space creatures do not understand stereo, so think of it really feel good poor. The universe is so big that we have nothing, and then I think of a creature that is lower than our dimension and suddenly feels like a god.

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The brain opens to the infinite answer let's smile, look at the interesting, and in case I guess right ...

Well, actually, I'm a Chinese teacher.