What is a black hole (black hole)?

The article below is the basic concept of black holes (or black holes), so you should consult.

What is a black hole (black hole)?

A black hole (black hole or black hole) is an area in space-time that gravitational fields prevent everything, including light, cannot escape.

General relativity predicts that a large enough mass of matter within a small enough range will deform space-time to become a black hole. Around the black hole is a face defined by mathematical equations called event horizons , where when matter passes it will not be able to escape out of the black hole.

The black hole is called "black" because it absorbs all radiation and matter sucked through the event horizon , like an absolute black object in thermodynamics; it is also not a kind of "hole" or "hole" but an area of ​​spacetime that does not allow anything to escape.

The black hole is called "black" because it absorbs all radiation and sucked matter through the event horizon.

The quantum field theory in spacetime curvature predicts at the event horizon the black hole emits radiation like a black object with a certain temperature that emits thermal radiation. This temperature is inversely proportional to the mass of the black hole, making it difficult to observe this radiation for stellar or medium black holes.

In theory, black holes of stellar mass form from the gravitational collapse of very massive stars in the final stages of evolution. After forming, they continue to attract material from the surrounding environment, and the volume increases gradually over time. Along with the process of merging and merging two or more black holes that exist giant black holes with masses ranging from several million to tens of billions of solar mass. Survey projects show that at most a large galaxy center exist at least one giant black hole.

Although by definition it is a completely black or invisible object, the existence of a black hole can be speculated through its interaction with the surrounding material environment and radiation as light. The matter that falls into the black hole forms on the accretion area, where matter collides and rubs together, becoming a plasma state emitting intense radiation; making the environment around the black hole become one of the brightest objects in the universe.

If there is a star orbiting the black hole, its shape and its cycle allows astronomers to calculate the mass of the black hole and the distance to it. These data help them distinguish the special object of a black hole or neutron star . In this way, many black holes are discovered in the binary star system, and at the center of the Milky Way there is a giant black hole with a mass of approximately 4.3 million solar masses.

The theory of black holes, where a strong gravitational field is concentrated in a small spacetime, is one of the theories that requires the synthesis of general relativity to describe gravity with the Standard Model of Mechanics. quantum. And now, theorists are still on the way to build quantum gravity theory to be able to describe the singular region at the center of the black hole.

The existence of black holes can be speculated through its interaction with the surrounding material environment and radiation as light.

The first direct measurement event announced by the LIGO group on February 11, 2016 also directly demonstrated the existence of a system of two black holes with mass stars rotating around each other and eventually merging to form a black hole. Turn larger volume.

Event horizon

The apparent surface of the black hole is defined at the event horizon - the boundary in spacetime, when it passes, matter and radiation can only go to the center of the black hole. Nothing, even light, could escape from the black hole outside the event horizon. The event horizon is defined as such because for events occurring within it, all the information of the event cannot go beyond to reach an observer far away from the black hole, making that person not I know what it is inside.

Exotic area

One feature of the general theory of relativity is that in experiments describing black holes, at its center there is an interesting singular region, where spacetime curvature has infinite value (or curvature of curvature). .

The way to call a singularity or an exotic singular circle is just a name for ease of popularity. They are usually performed in two or three-dimensional space for easy visualization. In fact, the singularity lies in the four-dimensional spacetime, and the attractive "singularity" is not the Euclidean geometry as its definition.