Three-dimensional and four-dimensional space

For four-dimensional space, there are more time axes than three-dimensional space. Most people may just think that there is a time axis on the axis of length, width and height, but most people still know little about it.

An expert once made an analogy: we assume that some plane people living in two-dimensional space have only one plane concept. If you want to lock a person in a two-dimensional plane, you just need to draw a circle around him with a line, so that he can't walk out of this circle in two-dimensional space anyway.

Now we who live in three-dimensional space interfere with it. We just need to take the two-dimensional person out of the circle from the third direction (that is, the direction in which the heel axis indicates the height) and put it back to other places in the two-dimensional space.

In our view, this is a simple thing, but in the eyes of two-dimensional film makers, this is undoubtedly incredible: how can a person suddenly disappear and then appear in another place when he is locked in a circle!

For us three-dimensional people, the situation in four-dimensional space is very similar to the above explanation. If we can overcome the four-dimensional space, it is not impossible to cross the three-dimensional space in an instant.

Let's do another experiment: weave some rubber ropes into a net according to the pattern of longitude and latitude, and flatten them. We can treat it as a two-dimensional plane approximately, and then put a ball on the net, and the rubber net sinks under the gravity of the ball, forming a three-dimensional space.

However, it is often unclear to observe this space from the inside, and those two-dimensional people may not realize that their living space has been distorted. When they come to this depression from the plane, and the depression is deep to a certain extent, or distorted to a certain extent, people from the two-dimensional plane may freely travel back and forth to the three-dimensional space.

In our three-dimensional world, an example of such a space-distorted sphere is a black hole. A black hole is actually a phenomenon existing in four-dimensional space, or a channel connecting the three-dimensional world and the four-dimensional space (of course, I'm not saying "whoever wants to go to the four-dimensional space, please go to the black hole", it will only be "dead and broke". It is possible for us to find a way to overcome the four-dimensional space through in-depth study of black holes. In that case, Wapu's jumping flight is no longer a dream.

Now scientists have confirmed that the existence of black holes will indeed distort the surrounding space extremely. According to the general theory of relativity, light travels in a straight line in normal space, but when space is distorted, light will be distorted with the direction of space distortion. If we can photograph a beam of light that shoots at the black hole, we will find that the light spirals at the center of the black hole, because the huge mass of the black hole has distorted the surrounding space.

But in fact, such photos can't be taken. Because black holes absorb light, we can't see it at all. How can we take photos (of course, the next one refers to ordinary optical photos. If it is a radio telescope, maybe we can take this strange scene)?

The concept of four-dimensional space ends here. I'm sorry to embarrass you with these obscure things.

References:

/cgi-bin/bbs/show/content？ groupid = 1020 1 & amp； messageid = 14202 & amp； titlepage=0

References:

/question/948 1 19 . html

Three-dimensional space, that is, what we call three-dimensional space, is a space composed of three axes, namely, abscissa, ordinate and ordinate. In this space, time cannot be changed, and we can only walk from one point to that point (theoretically. Actually, we can't fly, can we? Even if there is a plane, not every point can get here. There are other complicated reasons, but most of them can still be achieved. Four-dimensional space is to add time space to three-dimensional space, which means that time is also an axis. We can change the time, just as we can change our present position. Of course, this is just the need of some scientific assumptions. We don't know the specifics, but wouldn't it be a waste if the universe is too big to even have a four-dimensional space?

Traditionally, this space is a three-dimensional Euclidean space.

If it is four-dimensional, it is time+space, a four-dimensional space-time continuum.

I haven't seen other dimensions.

Some theories have 23-dimensional figures, but they are just numbers, and we don't even know what this means.

Think about two-dimensional space first.

Have a good time.

Draw a circle around one of the points.

Draw one by one.

The radius gradually increases.

If you are a capable person.

You will find that the edge of the circle will gradually straighten.

And then gather to another vertex.