What exactly is a black hole, find a master to discuss,

Light has mass, and at present theoretically there is no such thing as a massless object, of course, some objects are anti-mass, that is, its mass is anti-mass. As for black holes, let's put it this way: black holes have no size and can only exist at a single point, but for convenience, they usually use their event horizon to delimit their size, which is the range where light can just not be absorbed by it.

How dense are black holes? To put it this way: If the Earth were to become a black hole, then her horizon would be the size of a soybean.

I use my mobile phone to type so hard and write in layman's terms, thank you.

A black hole is just a celestial body...It's just that the mass is too big and too big...so that it can attract all the surrounding matter...Light is no exception....Black holes are invisible.

Alas, I see that my brother is not yet started, don't ask this question here, go back and make up for the foundation for two days before asking some valuable questions

Don't get me wrong, there's no mockery

Flowing water is used as an analogy to time, when flowing water meets stones, the flow rate slows down, and time is the same, and when it encounters a large mass, it will also distort, black holes are an example.

This mass is not the other mass, and the astronomical mass only says that it is very dense.

The black hole is formed by the death of the star and the large core of the star, which cannot be discovered and explained now, and the light cannot escape, his gravitational pull is very large, the mass is quite large, the weight of a needle angle is millions to tens of thousands of tons, he has particles that have not yet been discovered by human beings, which cannot be explained by the current physical theory, there may be millions of black holes in the universe, or not, or it may not be discovered when mankind perishes, and it cannot be explained...

Einstein used the limit operation of equations to prove the existence of black bai holes.

2.Stephen Hawking, a lifelong scientist who devoted himself to the study of black dao holes, popularized black holes and brought the study of black holes into a whole new field.

3.Cal. Schwarzschild mathematically proved the existence of black holes and the surrounding matter.

4.Roger. Penrose, mathematically proves the inevitability of the existence of singularities (black holes).

Black holes are present.

In the general theory of relativity, the universe.

A celestial body that exists in space. The gravitational pull of a black hole is so great that the escape velocity within the event horizon is greater than the speed of light.

In 1916, the German astronomer Karl Schwarzschild calculated a vacuum solution to Einstein's gravitational field equation, which showed that if a large amount of matter is concentrated in a point in space, a strange phenomenon will occur around it, that is, there is an interface around the particle point - once the "event horizon" enters this interface, even light cannot escape. This "incredible celestial body" was named a "black hole" by the American physicist John Archibald Wheeler.

A black hole is a celestial object with such a curvature of space-time that no light can escape from its event horizon."

Black holes cannot be directly observed, but their existence and mass can be known indirectly, and their effects on other things can be observed. Information about the existence of a black hole can be obtained by using the "edge information" of the rays emitted by the high heat before the object is sucked in. The existence of black holes can also be inferred by indirect observation of the orbit of stars or interstellar clouds.

On December 7, 2017, scientists at the Carnegie Institute for Scientific Research in the United States discovered the most distant supermassive black hole ever recorded, with a mass 800 million times that of the Sun.

Stephen Hawking, who has specialized in black holes, has a lot of interesting remarks. It was he who proposed the theory of black holes.

I haven't studied it, and I think it's too unrealistic.

The first one should be that the formation of a black hole greater than the Chandrasekhar limit is only a necessary condition, but beyond the Chandrasekhar limit it just doesn't turn the star into a white dwarf, and it can also become a neutron star or a quark star (the latter is currently a conjecture, and it has not been found that there is slightly more reliable evidence that a neutron star is a pulsar).

The second one is right.

And the third thing that should be understood is that a mass object bends straight space-time, and if you put an object on top of a piece of paper that is empty, the paper will be bent by a heavy object, and that's actually gravity. One of the things is that when you're putting an object that is too heavy, space-time can't support it, and it's like a quilt that completely wraps around the object, and you can't see the inside of the quilt (that is, outside the event boundary).

The mass of the star must be more than 30 times that of the Sun, and the remaining core of the supernova** will have enough mass to shrink and form a black hole, otherwise it will be a white dwarf, a neutron star, or something like that, for example, if the sun is not massive enough to form a white dwarf, as long as there are enough white dwarfs to attract each other and increase their mass in the years to come, and after a certain amount, they will also become black holes.

1 When a white dwarf exceeds the Chandrasechar limit, it will cause a type 1a nova**, 2 is correct, 3 is a massive star greater than 25 times**, and the core is greater than twice the mass of the Sun, which will form a black hole. Stars with more than 50 solar masses will have their cores collapse into black holes when they run out of fuel.

Personally, I think 1 is more accurate. Because the mass is too large to cancel out the attraction of its atoms to each other, it collapses towards the center, and finally the volume shrinks to infinitesimal is a point, but because its mass still exists, it will have a gravitational pull on the surrounding matter, for example, light will bend in this state, that is, because light waves are bent due to gravity in this state, of course, space-time is no exception, it will be distorted in this state. Finished...

To replace the curvature of space-time with the understanding of gravitation, I would like to use general relativity here. In fact, the root cause is that the mass of the star is greater than the mass of the Sun.

1A star with a mass less than the Chandrasekhar limit will become a white dwarf instead of a black hole.

2 A black hole is less than the Schwarzschild radius, and the radius of the star before the formation of the black hole can be greater than the Schwarzschild radius.

3 You change the curvature of space-time to the understanding of gravitation, and here you want to use general relativity. In fact, the root cause is that the mass of the star is greater than the mass of the Sun.

Black holes were first calculated by German mathematician Carl Schwarzschild, in the black hole around anything whether it is signal, light or matter can not escape, space-time here has become a bottomless pit, such a place that cannot be seen, touched or detected is called a black hole.

Scientists used Einstein's general theory of relativity to predict a celestial body called a "black hole".

A black hole, black, indicates that it does not emit or reflect any light electromagnetic waves to the outside world. The cave is anything that once it enters its borders, it will not want to slip out again.

To put it simply, a black hole is a massive star that collapses with the massive energy it has left, forming a point of infinite gravitational and gravitational forces. Due to its strong gravitational field, no matter can escape.

A black hole is a black galaxy-like thing, and its attraction is so strong that every object that comes close to it will be attracted to it, which is very scary!

A black hole is a very massive and dense object that can absorb other celestial bodies around it, even light.

To be honest, physics doesn't have a conclusive picture of what's going on inside a black hole.

However, as far as we know so far, it is certainly not possible to say that the velocity is constant. Theoretically, the space from the horizon to the singularity should be an absolute vacuum, the reason is simple, since the escape velocity here is greater than the speed of light, nothing can stay here for a moment, so anything once it enters this area will immediately and quickly fall towards the singularity, and it will accelerate towards the singularity. This is also easy to understand, even if you jump off a building on Earth, the process of a person falling from the building to the ground is an acceleration process, not to mention that the gravitational acceleration in a black hole is much greater than that of the earth's surface.

The concept of elements exists only at the atomic scale, while in black holes, the structure of the nucleus has long been completely destroyed due to the very high gravitational force. So in the black hole there will definitely be no "mixed elements". Even black holes don't have atoms in them.

Whether matter will exist in a black hole in the form of protons or neutrons is not yet known, but in fact the gravity at the center of the black hole is likely to be so great that it destroys the structure of both protons and neutrons, allowing matter to exist as a quark. As for whether the structure of the quark will be destroyed, it is even more difficult to say. As you know, we don't know anything about what quarks look like inside or what singularities look like inside.

But the conservation of matter and energy are universal laws in the universe, and not only that, but also the conservation of information, these three points are always true. So black holes will follow these three conservation laws.

I don't quite know if you're surmising from ** that black holes may not observe conservation of energy and mass. But that doesn't matter, because that thinking is wrong. I can tell you responsibly, certainly, and certainly, black holes not only obey the conservation of matter and energy, but also the conservation of information.

The escape velocity within the black hole horizon is already greater than the speed of light, and nothing will escape, including information. So we have no way of knowing anything within the horizon of a black hole. Only the mass of the black hole and the radius of the event horizon can be known.

Due to the huge gravitational pull of the black hole, no matter can resist the continuous collapse of the black hole, and even the molecules, atoms, and nuclei are crushed inside the black hole, so the "thing" mentioned in the question is not known at all. Even if there is "something", it is unknown, because black holes do not reveal any information about their interiors to you.

On the top three floors, there is only one singularity and an absolute vacuum inside the black hole.

Not necessarily, maybe black holes also have systems, hehe.

Scientists used Einstein's general theory of relativity to predict a celestial body called a "black hole".

Black hole is one of the three outcomes after the death of a star, when the star can no longer release energy, the star collapses inward due to its own gravitational force, and the result of the collapse has three results according to the difference in the remaining mass of the star: First, the small mass collapses into a white dwarf, and the state of matter that constitutes a white dwarf is called a super-solid state, which maintains a certain volume by the repulsion between electrons outside the nucleus.

Two: the medium mass collapses into a neutron star, and the state of matter that constitutes the neutron star is a neutron state, which is due to the compression of the huge gravitational force, and the electron repulsion of the super-solid substance cannot be resisted, so the electrons are pressed into the nucleus, we know that the number of protons in the nucleus of any substance is equal to the number of electrons outside the nucleus, so the protons and electrons combine to form neutrons. The entire neutron star is a huge atomic nucleus, made entirely of neutrons.

Three: the massive collapse into a black hole, on the basis of the neutron star, if the gravitational force increases again, to the point when the repulsion between the neutrons and the neutrons can not be opposed, so all the neutrons are crushed by the huge gravitational force, so the matter seems to "disappear", and is compressed into a point by the huge gravitational force. In this way, a black hole is formed.

A black hole is a celestial body that has a very large mass, a very small volume (within the Schwarzschild radius) and a very large gravitational pull. The gravitational force is so strong that if there is an object inside or on the surface of the black hole that glows, even the light will be pulled back by this gravitational force and will not be able to escape to the outside of the black hole.

So if we look at it from a distance, we can see that there is a small dark region where the black hole is located, and there is no light in it. But the inside of the black hole is empty, and all the matter that makes up the black hole is at the singularity at the center of the black hole.

A black hole is an extreme distortion of time and space.

A black hole is not black, it is not a hole, it is a high-density object formed by the collapse of a massive star after death, because it is very massive, so the gravitational pull is so strong that light cannot escape, so we can't see it. The gravitational pull is so strong that it can attract other celestial bodies and compress them.

A black hole is because it is too big, the gravitational force is too great, the matter can't resist gravity, it collapses into a black dot, and even the light can't come out.

For example, a star more than 40 times larger than the Sun, when the star's hydrogen and carbon atoms (so-called fuel) are used up, the star will become a white dwarf, and then the white dwarf will run out of carbon atoms, and iron will be produced in the white dwarf (iron can absorb energy), and finally the white dwarf will shrink and eventually become a black hole! (The sun does not turn into a black hole) (white dwarfs can absorb hydrogen atoms from other stars and continue to change (upgrade) until a black hole), and there are super-black holes in the universe.