BLACK HOLE

BLACK HOLE

A black hole is an area of ​​space-time where gravity is so strong that no particles or even light, such as electromagnetic radiation, can escape it. General theory of relativity predicts that a compact mass can spoil space-time. . The extent of the escape is called the horizon event. Although the fate and circumstances of an object crossing it are greatly affected, it does not have locally identifiable features according to the general relationship. In many ways, a black hole acts like an ideal black body, because it does not reflect light. Furthermore, in curved spacetime, quantum field theory predicts that the event horizon emits Hawking radiation, with the same spectrum whose black body temperature is proportional to its mass. This temperature is at billions of calories for stellar massive black holes, making it virtually impossible to observe directly. 

Objects whose gravitational field is too strong to withstand light were first considered in the 18th century by John Mitchell and Pierre Simon Laplace. Carl Schwarzschild, the first modern solution to the common relationship characteristic of a black hole, was found in 1916 to define space as an area where nothing could escape. It was first published in 1958 by David Finkelstein. It wasn't until the 1960s that theoretical work showed that they were general predictions of a normal relationship. The discovery of neutron stars by Jocelyn Bell Burnell in 1967 aroused interest in compact objects collapsing under gravity as a possible astronomical medical reality. The first black hole, called the Cygnus X-1, was independently identified by several researchers in 1971. 

Darkness becomes a massive black hole when huge stars fall at the end of their life cycle. Once a black hole is formed, it can continue to grow by absorbing mass from its surroundings. By absorbing other stars and merging with other black holes, millions of solar masses (M☉) could form huge black holes. It is agreed that the centers of most galaxies have extremely large black holes.

The presence of a black hole can be gauged from its interaction with other matter and visible light such as electromagnetic radiation. Matter that falls on a black hole can form an external action disc that heats up with friction, forming a quasar, some of the brightest objects in the universe. Stars passing close to a very large black hole can be smashed into a streamer that "shines very brightly before being swallowed." Can be used to determine. Neutrons will be used to exclude possible alternatives such as stars. Supermassive black holes of about 4.3 million solar masses. 

On February 11, 2016, LIGO Scientific Collaboration and Virgo Collaboration announced the first direct detection of gravitational waves, which also represents the first observation of black hole integration. Ten merging black holes (with one binary neutron star integration). On April 10, 2019, the first direct image of the black hole and its surroundings was published, following observations of the 2017 Horizon Telescope (EHT) event of the supermassive black hole at the galactic center of Messier 87. In March 2021, EHT Collaboration for the first time presented a polarized-based image of a black hole that could help better reflect the forces that give rise to quasars. 

By 2021, the nearest known body known as a black hole is about 1,500 light-years away (see list of nearest black holes). Although only two dozen black holes have been found in the Milky Way so far, it is thought that there are millions of them, most of which are solitary and do not emit radiation, so only gravitational lensing can detect them. Will be able to walk.                                                                                                                                         

                                                                                                                                        

HISTORY OF BLACK HOLE                                                                                                                                                

The discovery of Saginaw X-1 in 1964 filled a lost piece of Einstein's puzzle and broadened our understanding of the universe.                                                                                                                                                                                                                                                           

What we know about black holes originated during the Great War. Imagine this scene: December 1915. Europe and the world are struggling under the dark clouds of World War I. Somewhere on the eastern front, at the bottom of an old German artillery, fighting to stay warm and dry. .

With numb and trembling fingers, he opens the latest delivery from home. A particularly heavy package attracts his attention. Tonight, throwing caution into the air, he risks using an electric light to read a long and detailed report. Little did he know that this would be the most important work of creative intelligence in the 20th century.

The author of this important document was a theoretical physicist named Albert Einstein. The recipient was his colleague Carl Schwarzschild, director of astronomical observations at Potsdam and an expert theorist and mathematician. Despite his astronomical career, Schwarzschild, again in his 40s, became involved in combat efforts.

Just a few weeks ago, Einstein completed 10 long dedicated works, successfully advancing his special theory of relativity to combine gravity with electricity and magnetism. In four historical articles published in the Prussian Academy of Sciences, Einstein laid the mathematical basis for the general theory of relativity, which is considered to be one of the most beautiful scientific theories ever.                                                                                                                                                                                                                                                                                                  

The Rise of the Magnum Ops was published on November 25, 1915, under the title "Field Equations of Gravity". Although it can be a bit confusing for anyone without a strong grasp of tensor calculus, the field equation can be clearly summed up in the words of the great physicist John Wheeler: "Space time tells how matter moves. Space time Explains how to rotate.

Like MC Escher's famous picture of two hands sketching each other, Einstein's circular argument for field equations makes them both beautiful, but also notoriously difficult to solve. At the root of this problem is Einstein's most famous equation, E = mc2, which states that energy and matter are interchangeable. Because gravity is a form of energy, it can behave like matter, and produce more gravity. Mathematically, normal relationships are a nonlinear system. And the non-liner system is really hard to solve.                                                                                                                                                                                                                                                                                                                                                                                                

It is easy to imagine Einstein's shock when, during a terrible war, Schwarzschild wrote in a few days describing Einstein's first known solution to the field equation. Schwarzschild wrote politely, "As you can see, the war treated me well, despite the heavy bullets, allowing me to get away from them all and walk in the land of my thoughts." Einstein replied, "I have read your paper with great interest. I did not expect anyone to come up with a simple solution to a problem in such a simple way. Liked it a lot                                                                                                                                                                                                                                                                                                                                                                                                               

For this reason, early physicists study these strange things, often calling them "frozen stars." Today, we know them by the name Wheeler used in 1967: Black Holes. Although Event Horizon played a vital role in Schwarzschild's solution, it took many years to accept black holes as something other than mathematical curiosity. In public relations in the first half of the 20th century, most of the world's leading experts were convinced that black holes could never really exist. Arthur Eddington insisted, "There must be a law of nature to prevent a star from behaving this way."

Complicating the problem was the simultaneous development of quantum mechanics, a new field that behaves almost entirely in terms of nature. Physicists working at the intersection of quantum mechanics and general relativity began to appreciate how important both fields are for understanding extremely large and dense stars. But the strange nature of these new branches of physics also put pressure on the most gifted insights, so that even 50 years after Schwarzschild's historical paper, there could be no consensus on the existence of black holes.