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How do black holes form? Introduction to the formation process and composition of black holes

Recently, the Chinese Academy of Sciences discovered the largest black hole so far. This black hole with 70 times the mass of the sun far exceeds the mass limit predicted by the theory, subverts people's cognition of stellar black hole formation, and is expected to promote the innovation of stellar evolution and black hole formation theory. This news has attracted the attention and heated discussion of many netizens. Do you know how black holes are formed? What material is a black hole made of? Let's take a look at this article.

How do black holes form

black hole

The formation of black holes is similar to that of neutron stars.

When a star is preparing to perish, its core rapidly shrinks, collapses and explodes under its own gravity. When all the matter in the core becomes neutrons, the contraction process stops immediately and is compressed into a dense star. At the same time, it also compresses the internal space and time. But in the case of a black hole, because the mass of the stellar core is so large that the contraction process goes on endlessly, even the repulsive force between neutrons can not be stopped. The neutron itself is crushed into powder under the attraction of squeezing gravity itself, and the rest is a matter with unimaginable density. Due to the gravity generated by high mass, any object close to it will be absorbed by it.

It can also be simply understood as: usually, stars only contain hydrogen at first, and the hydrogen nuclei in stars collide with each other and fuse at all times. Due to the large mass of stars, the energy generated by fusion competes with the universal gravitation of stars to maintain the stability of stellar structure. The fusion of hydrogen nuclei produces a new element - helium. Then, helium atoms also participate in fusion, change their structure and produce lithium. By analogy, beryllium, boron, carbon and nitrogen will be formed in the order of the periodic table of elements. Until iron is formed, the star will collapse. This is because the iron element is quite stable, and the energy released when participating in fusion is less than the required energy, so the fusion stops. However, the iron element exists in the interior of the star, resulting in insufficient energy in the interior of the star to compete with the gravitation of the massive star, which leads to the collapse of the star and the final formation of a black hole. It is said to be 'Black' because its gravity makes it impossible for the light around it to escape. Like neutron stars, black holes evolve from stars whose mass is dozens or even hundreds of times greater than that of the sun.

When a star ages, its thermonuclear reaction has exhausted the fuel in the center, and the energy generated by the center is running out. In this way, it no longer has enough strength to bear the huge weight of the shell. Therefore, under the weight of the shell, the core begins to collapse, and the matter will march unstoppably towards the center until a star with a volume close to infinity and a density almost infinity is finally formed. Once its radius shrinks to a certain extent (must be less than the Schwarzschild radius), the distortion of space-time caused by mass makes even light unable to emit outward -- 'black hole' is born.

What material is a black hole made of?

A black hole is a singularity with infinite density, infinite curvature of space-time, infinitely small volume and infinite heat in the center and a part of the empty sky around it. It is invisible within the scope of this sky. According to Albert Einstein's theory of relativity, when a dying star collapses, it will gather and become a black hole, swallowing all light and any matter in the adjacent universe.

Compared with other celestial bodies, black holes are very special. People can't observe it directly, and scientists can only put forward various conjectures about its internal structure. The reason why black holes hide themselves is curved space-time. According to general relativity, space-time will bend under the action of gravitational field. At this time, although the light still travels along the shortest optical path between any two points, it is relatively bent. When passing through dense celestial bodies, space-time will bend and light will deviate from its original direction.

On earth, due to the small effect of gravitational field, the distortion of space-time is very small. Around the black hole, the deformation of space-time is very large. In this way, even if the light emitted by the star blocked by the black hole will fall into the black hole and disappear, the other part of the light will bypass the black hole through the curved space and reach the earth. Observing the starry sky on the back of a black hole is like a black hole does not exist. This is the invisibility of a black hole.

More interestingly, some stars not only send light energy towards the earth directly to the earth, but also the light emitted in other directions may be refracted by the strong gravity of nearby black holes and reach the earth. In this way, we can see not only the 'face' of the star, but also its' side 'and even its' back', which is the 'gravitational lens' effect in the universe.

If the black hole is large enough, astronauts will begin to realize that the gravity pulling his feet is stronger than the gravity pulling his head. This attraction drags him relentlessly downward, the gravity difference will increase rapidly and tear him apart (stretch line), and finally his body will be decomposed and fall into the infinite dense core of the black hole.

Pkinski and his two students Ahmed & middot; Amhari, James & middot; Sally, together with Donald & middot, another string theorist at the school; Together with malov, the incident was recalculated. According to their calculations, it presents a completely different scene: the quantum effect will turn the event horizon into a boiling particle vortex, and anything falling in will hit a flame wall and be instantly scorched.

NASA is concerned about a supermassive black hole and its surrounding material disk. Hot material clusters (one pink and one yellow) each have a volume equivalent to that of the sun and orbit closer to the black hole. Scientists believe that supermassive black holes exist in the centers of all large galaxies. Black holes have been swallowing up material called 'active galactic nuclei'. Surrounded by a bright and extremely hot disk of falling matter, the mass of a black hole is difficult to determine. According to a research paper published in the journal Nature, based on the calculation results of the rotation speed of matter around the black hole, the mass of the black hole in the center of 37 known galaxies is actually lower than previously expected.