When entering the black hole adventure, what kind of magical space -time structure can we see?

Written article | Dong Weiyuan

Black Hole is a frequent visitor in the popular science content, such as "Space -Time", "Event Horge", and "Swana Rie". These terms have long become a well -known concept of enthusiasts. But if you talk about the multi -layer structure inside the black hole, I am afraid that many people will feel inexplicable. There is no material in the black hole. Only the severe distorted space -time. How can there be a layered structure like eggs? In fact, the black hole has not only the internal structure but also complicated, but we can start from "0".

0 sugar 0 card 0 formula

In fact, the black holes that often appear in popular science books are just the simplest type in the black hole family, known as Swaixi Black Hole. This black hole neither charges nor self -transfer, only one physical attribute -quality. Under the premise of such a high degree of simplification and symmetry, of course, there is no chance to appear too complicated. However, in the real universe, most of the celestial bodies have self -rotation momentum, and they also have some charge, and black holes should not be exceptions. When the theoretical model described the black hole was added with the angle volume and charge, some interesting structures appeared.

Black holes classification under general relativity

We all know that the structure of the Swani black hole is a sphere called the events of the event, wrapped in the spatial space of the ball heart, from the perspective to the strange point area is an irreversible one -way area, falling into this area Nothing is inevitable to go to the strange point. There is a sense of gimmick: in this one -way area, time becomes space and space becomes time. As for how to understand this sentence, let's talk about it later.

Now we let the black hole carry the charge, that is, the RN black hole. It has two layers of vision in the inside and outside. The unidirectional area only exists between the two layers of vision. The more the black holes are charged. Essence The area within the internal vision returns to ordinary time and space. There is no case where time and space -dimensional replacement are existing. The strange point of the center of the black hole is lying in this ordinary space -time area.

If the black hole has a self -rotation, that is, the Kell Black Hole, its vision is no longer a well -proportioned sphere, but a surface similar to pumpkin, and this pumpkin -like vision also has two floors in the inside and outside, with one -way area in the middle. In addition, there are two more interfaces than the RN black holes -the static stop and the inner static surface -located outside the outside world and within the interior world. The area from the static surface to the vision is called the energy layer. The origin of the name is Penrus found that energy can be obtained from this area. The most interesting part of the Kell Black Hole is that the center no longer exists, and it is replaced by a strange ring.

The structure displayed by the Kell Black Hole has basically reached the limit of complexity, and then the charge of Krel Newman Black Hole with the charge is not more complicated in the structure of the Bikkle black hole. In the area of ​​the area, the middle is still a strange ring representing the strangeness of time and space. The amount of charge is only an additional parameter for the specific position of these structures.

Swana

At this point, we have browsed the structure of the four black holes, but I believe most readers will definitely not be satisfied with such a general horse. In order to speak more clearly, we first met the physical concepts of the two theory for half a minute- "line element" and "rules".

"Line Yuan" can be roughly understood as a small interval near two points in time and space. In straight time, air,

Or adopt the form of pole coordinates

The appearance of writing as a vector is

The 4 × 4 matrix sandwiched in the middle is the "rules", which shows the geometric nature of time and space. The degree of straight time and space is a simple Diag (-1, 1, 1, 1) diagonal matrix, and the score of bending time and space will become complicated.

The so -called solution of Guangyi relativity equation is actually calculating all the weights of the output regulations. All portrayal of time and space geometry is hidden in this matrix.

Knowing this, we can read the time and space according to the expression of a line element, and then look like time and space. For example, put the objects that do not transfer, do not bring charged, and the mass of M are placed in the original point of the polar coordinate.

in

We can immediately see that this Swadani gauge is still a diagonal matrix, but compared to the appearance of straight time and space, the two components marked into blue and GRR are obviously different. These two are all post -theory era For the starting point of the black hole research, the RS is the radius of the Swani, and the R = RS is the horizon of the Swani black hole.

When S → ∞, Swadisu's regulations returned to straight time and space, indicating that the effect of bending in time and space in infinity gradually disappeared. So how is the time and space near the black hole bent? Let's send an adventurer to a place near the world for inspection. In the three -dimensional space, the position of the adventurer is at a point, and the four -dimensional time and air, due to the continuous passage of time, even if the adventurer rests still, this position is still a line, known as the "world line".

The time near the black hole expands

The theory of relativity tells us that the world line is an absolute physical object. No matter from which reference system, the length of the same DS on this line must be the same. We choose two special reference systems, one is the reference system of relatively static black holes, and the other is the adventurer's own follow -up department.

In the previous reference department, we used the formulas that have been mentioned as usual to calculate the line element of the adventurer's world line.

in

It means changing the position of the side of the ball, together with the radical position DR, to give the adventurer's space coordinate position change. It should be noted that the DT in the formula represents the changes in the time of the time where the viewers who stand in an infinite distance and relative to the static black hole. In the latter reference department, the adventurer did not change from any position relative to the follow -up department, but simply experienced the passage of time, so the line element simplified into it

Among them, Dτ is the time change that the adventurer feels.

The world line of the two references in the department is the same, so

Now, we ordered the adventurer to hang, so the DR and DΩ are 0, and the formula is simplified to

If the position of the hover is satisfied, there will be DT≈10Dτ, and the clock of the adventurer will become slow! The viewers at the end of the infinity have to wait for ten years to see that the adventurer is one year old. This is the time expansion effect generated by the gravitational venue. If the adventurer launch a light at this time, then the time frequency of the viewer who has reached the distance has dropped to one -tenth of the departure, that is, a serious red shift.

When the position of the adventure is infinitely close to RS, the expansion of time is infinitely close to infinite. Although the adventurer himself still experiences the passage of normal time, from the perspective of viewers in the distance, the adventurer's time has almost stopped, and the light emitted by the frequency is infinitely close to zero. In other words, the light from the perspective cannot pass the energy to the distance. Suddenly, I thought that there were so many TV shows and even the radio station were willing to give the "vision" as a name, which could not help but feel ...

Space dimension becomes time dimension

Speaking of physics, let's take a look at the scenes of the adventurer passing through the horizon and entering the black hole. Some people may question: The adventurer has reached the limit of time expansion at the field of vision. Even if the viewers in the distance wait for the destruction of the earth, they can't wait to pass the adventurer through the vision?

Little, the pattern is small.

Although the viewers in the distance cannot wait in the time they experience, they do not mean that the adventurer cannot reach. In fact, according to the time of the adventurer's own experience, he can reach the horizon within a limited time and pass through the horizon. Of course, he is best to have a very hard armor and a very small body, so as not to be crushed by the tide.

When R

at this time

Still establishing.

In order to make the adventurer feel the time Dτ is the real number, the left side of the number must be negative, and when R

Can only rely on

This contribution.

In other words, the adventurer after entering the horizon can no longer hang anywhere, he must keep approaching the center of the black hole in order to feel the passage of time. Or simply say that the space dimension R in the distant viewer's reference to the department has established a wonderful correspondence relationship with the time dimension in the adventurer's reference. For adventurers, R is no longer a spatial dimension that can move back and forth, but becomes a one -way dimension with time.

RN degrees and Kerrity rules

Through the previous understanding of the Swaizas, we found that the origin of the black hole appeared in a place where the measurement of the rules was zero or the divergence. According to this experience, recognize the vision of other types of black holes, and naturally you can also catch it. This is the RN degree that is only charged and does not rotate:

in

Determining the position of the horizon is very simple, only a small equation requires a small equation

Get

This is the two horizons of the RN black hole.

When R- 0, GRR <0, the space dimension R becomes a unidirectional dimension. In the area of ​​R 0, Time Concentration Space Maintenance returns to ordinary appearance.

Readers who can insist on reading here are estimated that at this time it will have an illusion -what mysterious space -time is bent, so it is just that! Well, let's take a look at the Callene of Callene, which is not charged, only with the rotary momentum J.

in

Obviously, the space -time structure described by this rules is much more complicated than the Swaizas regulations and RN degrees, so it has been calculated for a longer time. Swadava was discovered as early as 1915, and the RN degree was also discovered between 1916 to 1918, but the precise solution of Klidan was waiting until 1963.

Kerrity is not only complicated and important, because the celestial bodies in the universe have more or less self -rotation momentum, and only Kerrity can more accurately reflect the movement and evolution of these celestial bodies. In comparison, the Swaizas and RN degrees are too simplified, and even missed many interesting content in the real universe.

The rotating black hole can be generated

In the Swadas Grade and RN degree, the position of GTT = 0 is also the position of GRR → ∞, so this position is logically defined as the horizons of black holes. However, in the Callene, the positions that meet these two conditions are no longer rearranged.

Solution GTT = 0 Formula obtained

Solve this equation obtain

These two sets of solutions correspond to the four interfaces, which definitions should be defined as the horizon?

In the description of the adventurer's journey before memories, we can summarize two conclusions:

When the adventurer hangs in a certain position of the space, his time passing speed is proportional to the viewer in the distance. When GTT = 0, the adventurer seen by the viewers in the distance is completely still.

At the place where GTT <0, the space dimension R becomes a unidirectional dimension like time dimension T. The adventurer cannot hang in the space a little, and you must continue to move in the direction of R. These two are universal for all time and space, and can also be used to examine the rules.

If the adventurer went to a Kell black hole, when he arrived at the RE+position, in the distance, he was still, but in fact he could continue to move forward, and even if he entered R

Therefore, RH is the horizon of the incident of the black hole, and the position of the RE is named the static surface, also known as the infinite red shift surface. In this place, the light emitted in this place cannot bring energy to the distance. Attentive readers may ask, where can the adventurers escape from the place where the light cannot escape? This is related to the special geometric characteristics of this area between Re -to Rh.

In this area, GTT ＞ 0 and GRR> 0, it seems that time -dimensional Rights have become "spatial dimensions". In order to allow the adventurer to have a real number of time τ, a negative contribution must be found in the online meta expression.

It has become the only source of contribution that can be expected. It can be seen that in the region between RE and RH, φ is a dimension that cannot stop changing forever. This is the extreme drag effect of the rotating black hole on the surrounding space.

The time and space that is rotated at this moment is called the energy layer, because it contains a special energy. The adventurer who enters this area can throw a quality object in the direction of rotation, and you can get a lot of energy. Then use these energy to escape from the static surface. The practice of this car losing the car Baoshuai is called "Penrose Process", which was discovered in 1969.

We know that quality is a form of energy, and Pueros process is essentially the method of using the capable layer of the Kerl black hole to convert the quality into energy. Moreover, the efficiency of this energy exchange method is very high. In the quality of we feed to the black hole, theoretically at most 29%can be transformed into the energy we get. Don't look at this efficiency about the efficiency of boiling water with coal, but don't forget that our denominator is not the chemical energy in coal, but the quality of the whole material.

The shape of the event horizon

Kerrnman with a rotary moment J and charge Q is a small extension of Klidan.

It can be seen that this schedule is basically not much different from the space -time structure described by Kerr's regulations. We can also find the location of the static surface and the line of events through GTT = 0 and these equations.

and

You need to make some supplements here. Regardless of the Kell Black Hole or Kell Newman Black Hole, the calculation result of the view of the incident is that Rh is a certain value that has nothing to do with coordinate parameters, and it seems to be a spherical side. But why does the image given in the image given into a pumpkin shape?

In fact, this is also a result of time and space distorted. If R = RH, dt = DR = 0, that is, fixing the time, and fixing the position at RH, the Klidian line meta expression becomes

This expression obviously does not have ball symmetry.

However, we must not say that this is the black hole that "see" in the eyes of the adventurer, because it involves the problem of light communication routes, which will make the problem more complicated. We can only let the adventurers close our eyes, avoid the deceptiveness of light, and reach the actual space position with our hands. Due to the severe distortion of the time and space at the black hole, the adventurer will find that the 3 -dimensional indicator map that the viewers at the beginning of the distant viewer will become a flat pumpkin in the black hole.

There are more questions than answers

There are too many research topics related to black holes. In addition to the black hole thermodynamics and information paradoxes that have attracted much attention, the many natures of time and space geometry itself are the frontier of active research. For example, the destruction of time and space causality structure has made many researchers very disturbed: Since it cannot be theoretically eliminated, it is very hoped that it will always be hidden in the field of events and not exposed to the time and space we can touch.

However, when calculating RH, it can be seen that if RQ or A is large enough, that is, the charge or angular amount is large enough, then it is possible to have no solution from mathematics. Essence If so, the strange point will be exposed in front of us, which is a very resistant scene in the hearts of physicists. To this end, Penrose proposed the "Cosmic Censorship Hypothesis), thinking that there must be some mechanism in the universe to prevent nakedness from appearing. As for what this mechanism is, there is no particularly powerful theoretical mechanism so far.

In addition, since knowing that the black hole is an ultra -high energy converter, the stability of its own structure has also become a problem that physicists worry. Just like the workshop that produces gunpowder is more likely to explode, a particle that enters the black hole may obtain huge energy due to the occasional decline. These energy may make the particles become a small black hole in place. If there is such a process, this small black hole may cause irreversible damage to the space -time structure of the big black hole, and even cause the overall structure of the large black hole to collapse.

The research on the stability of the Kel black hole's own structure is a very difficult topic. It has been relatively slow in nearly 60 years since 1963. In May 2022, several researchers from Columbia University and Princeton University finally gave the stability proof of the Kell Black Hole under the conditions of a 912 pages of the 912 papers [1]. The proof process of this paper also uses more than twenty rats that several researchers have obtained in the past few years. If you calculate the papers that have been paved before, there are more than 2100 pages! This shows the complexity of this issue in mathematics. Although the topics related to Black Hole are such difficult and hard bones, these issues are also related to the most basic laws and rules of our universe. In -depth research on these issues, even if you cannot get a clear answer immediately, will become a "hen with golden eggs". We will create richer tools and constantly refresh our cognition.

literature

[1] Arxiv: 2205.14808 [math.ap]

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