Black holes swallow all matter, so where does the matter swallowed by the black hole go?

The matter in the universe includes planets, moons, stars, galaxies, galaxy clusters, intergalactic matter, dark matter, dark energy, etc., where stars originate from interstellar matter. Interstellar matter fills the entire cosmic space with an average density of 10-24 g/cm.

When a certain amount of interstellar matter is gravitationally perturbed, then as long as certain conditions are met (Gins mass), the gravitational force between the interstellar matter becomes the dominant driving force, causing them to collapse into denser nebulae. When the nebula is dense enough, it will split into several clumps. The clumps are denser than the nebula, so they continue to collapse and split.

When the mass of the clump is as small as 0.08-150 solar masses, it will not continue to break up, and the material inside it will then clump together again. When a certain threshold is reached, the gravitational pressure ignites the thermonuclear reaction inside the clump, and a star is born.

When a star is born, it contains only hydrogen, and the nuclei of hydrogen atoms inside the star keep colliding with each other at the high-speed moment by moment, thus triggering a nuclear fusion reaction. Due to the large mass of the star, the energy generated by the fusion reaction is in opposition to the gravitational force of the star, and when the two reach a dynamic equilibrium, the star can maintain its structural stability.

The fusion reaction of hydrogen nuclei produces a new element, helium. Immediately afterward, helium atoms also participate in the fusion reaction. The fusion reaction of helium atoms in turn produces the element lithium. and so on, according to the order of the periodic table of chemical elements, the fusion reaction inside the star will also produce beryllium, boron, carbon, nitrogen, etc., in turn, until the production of iron.

Because iron is relatively stable, it is involved in the fusion reaction when the energy released is less than the required energy, "not enough", then the fusion reaction will not be able to continue, so it can only stop. The presence of iron in the interior of the star causes the star to collapse if it does not have enough energy to fight the gravitational force of the massive star.

The collapse of the star means that it is on its way to destruction. The core of the star rapidly contracts and collapses under its gravity, followed by a powerful explosion. When all the matter in the core of the star becomes neutralized, the collapse stops, and the entire star is compressed into an extremely dense body, including space and time.

However, in some cases, even the repulsive forces between neutrons cannot stop the process because the mass of the stellar core is so large that the contraction process goes on endlessly. At this point, the neutrons are crushed to powder by the attraction of the squeezing gravity.

What remains is a star with a volume close to infinity and a density close to infinity (almost a singularity), and once its radius has contracted to a certain point (less than the Swastika radius), the distortion of space-time caused by the mass makes it impossible for even light to escape, and thus, a "black hole" is born.

Compared to other celestial bodies, a black hole is very special because it cannot be observed directly and scientists can only speculate about its internal structure. Why can't people see a black hole?

The reason is the distortion of space-time. According to Einstein's general theory of relativity, space-time will be bent under the action of the gravitational field. At this point, although the light will still travel along the shortest distance between any two points, it has been bent in relative terms. On Earth, due to the small effect of the gravitational field, the distortion of spacetime observed at this time is minimal or even not observed at all. But around a black hole, the spacetime distortion is very large.

In this way, part of the light emitted from the luminous star is directly swallowed by the black hole, while another part will bend space-time around the black hole and reach the Earth and be seen by people on Earth. Therefore, people can observe the stars at the back of the black hole, but not the black hole itself.

It was not until 2019 that the first human photograph of a black hole was released, showing a black hole at the center of a giant elliptical galaxy M87 in Virgo, 55 million light-years from Earth and about 6.5 billion times the mass of the Sun.

The gravitational force of a black hole is so strong that it can swallow any matter that comes close to it, and even light has no way to escape the gravitational force of a black hole. So, how does a black hole swallow matter?

Let's take an ordinary planet as an example. When a planet approaches a black hole, the gravitational force of the black hole tears it into pieces, and these pieces rotate around the black hole while moving closer to it. Due to the conservation of angular momentum, the closer these fragments are to the black hole, the faster they rotate around the black hole. As the matter becomes denser and denser, a large amount of matter will form a disk-like structure around the black hole that rotates around it at high speed, called an accretion disk. Eventually, all the matter will be swallowed by the black hole.

Where does the matter swallow up by the black hole end up?

Stephen Hawking believes that while a black hole is swallowing all matter, it is also releasing energy outward, a process known as Hawking radiation. Specifically, the matter swallowed by the black hole is reconverted into energy, which is then released outward into the universe in the form of "evaporation" through Hawking radiation.

According to Hawking's theory, each black hole has a certain temperature, the temperature of which is inversely proportional to the mass of the black hole. The higher the temperature of the black hole, the more intense the "evaporation" will be. In general, the evaporation rate of a black hole is extremely slow. A black hole with the mass of the Sun would take about 10 years to evaporate 0.0000001% of its mass.

Nevertheless, Hawking believes that, with time, all the black holes in the universe will eventually evaporate. At that point, the entire universe will be on its way to destruction.