There is no cosmic phenomenon more mesmerizing with its beauty than black holes. As you know, the object got its name due to the fact that it is capable of absorbing light, but at the same time it cannot reflect it. Due to the huge attraction, black holes suck in everything that is near them - planets, stars, space debris. However, this is far from all there is to know about black holes, as there are many amazing facts about them.

Black holes don't have a point of no return

For a long time it was believed that everything that falls into the region of the black hole remains in it, but the result of recent research is that after a while the black hole "spits out" all the contents into space, but in a different form, different from the original. The event horizon, which was considered a point of no return for space objects, turned out to be only their temporary refuge, but this process is very slow.

The earth is threatened by a black hole

The solar system is only a part of an endless galaxy, which contains a huge number of black holes. It turns out that the Earth is threatened by two of them, but fortunately, they are at a great distance - about 1600 light years... They were found in a galaxy that was formed as a result of the merger of two galaxies.


Scientists saw black holes only due to the fact that they were near the solar system using an X-ray telescope, which is able to capture the X-rays emitted by these space objects. Black holes, since they are next to each other and practically merge into one, were named by the same name - Chandra in honor of the moon god from Hindu mythology. Scientists are confident that Chandra will soon become one because of the enormous force of gravity.

Black holes can disappear over time

Sooner or later, all the contents of the black hole come out and only radiation remains. Losing mass, black holes become smaller over time, and then completely disappear. The death of a space object is very slow and therefore hardly any of the scientists will be able to see how the black hole decreases and then disappears. Stephen Hawking argued that the hole in space is a highly compressed planet and that it evaporates over time, starting at the edges of the distortion.

Black holes may not necessarily look black

Scientists argue that since a space object absorbs light particles without reflecting them, a black hole has no color, it only gives out the surface - the event horizon. With its gravitational field, it obscures all space behind it, including planets and stars. But at the same time, due to the absorption of planets and stars on the surface of a black hole in a spiral, due to the tremendous speed of movement of objects and friction between them, a glow appears that can be brighter than stars. It is a collection of gases, stardust and other matter that is sucked in by a black hole. Also, sometimes a black hole can emit electromagnetic waves and therefore can be visible.

Black holes are not created out of nowhere, they are based on an extinguished star

Stars glow in space thanks to their supply of thermonuclear fuel. When it ends, the star begins to cool, gradually turning from a white dwarf to a black one. The pressure inside the cooled star begins to decrease. Under the influence of the force of gravity, the space body begins to contract. The consequence of this process is that the star explodes, as it were, all of its particles scatter in space, but the forces of gravity continue to act, attracting neighboring space objects, which are then absorbed by it, increasing the power of the black hole and its size.

Supermassive black hole

The black hole, which is tens of thousands of times the size of the Sun, is located in the very center of the Milky Way. Scientists named it Sagittarius and it is located at a distance from the Earth 26,000 light years... This region of the galaxy is extremely active and absorbs everything that is near it with great speed. She also often "spits out" extinguished stars.


It is surprising that the average density of a black hole, even given its huge size, can even be equal to the density of air. With an increase in the radius of the black hole, that is, the number of objects captured by it, the density of the black hole becomes less and this is explained by simple laws of physics. Thus, the largest bodies in space can actually be as light as air.

Black hole can create new universes

As strange as it sounds, especially against the background of the fact that black holes actually absorb and accordingly destroy everything around, scientists are seriously thinking that these space objects can initiate the emergence of a new Universe. So, as you know, black holes not only absorb matter, but can also release it at certain periods. Any particle that emerged from the black hole can explode and this will become a new Big Bang, and according to his theory, our Universe appeared that way, because it is possible that the Solar system that exists today and in which the Earth revolves, inhabited by a huge number of people, was once born by a massive black hole.

Time passes very slowly near a black hole

When an object comes close to a black hole, no matter what mass it has, its movement begins to slow down, and this happens because in the black hole itself time slows down and everything happens very slowly. This is due to the tremendous force of gravity that the black hole has. At the same time, what happens in the black hole itself happens quickly enough, therefore, if the observer looked at the black hole from the side, it would seem to him that all the processes occurring in it are proceeding slowly, but if he fell into its funnel, the forces of gravity would instantly tore it up.

« Science fiction can be helpful - it stimulates the imagination and relieves fear of the future. However, the scientific facts can be much more startling. Science fiction never thought of things like black holes»
Stephen Hawking

In the depths of the universe, a countless number of mysteries and secrets lurk for man. One of them is black holes - objects that even the greatest minds of humanity cannot understand. Hundreds of astrophysicists are trying to uncover the nature of black holes, but at this stage we have not even proven their existence in practice.

Filmmakers devote their films to them, and among ordinary people, black holes have become such a cult phenomenon that they are identified with the end of the world and imminent death. They are feared and hated, but at the same time they idolize and bow before the unknown that these strange fragments of the Universe conceal within themselves. Agree, being swallowed up by a black hole is still romance. With their help it is possible, and also they can become guides for us in.

The popularity of black holes is often speculated by the tabloids. Finding headlines in newspapers related to the end of the world on the planet due to another collision with a supermassive black hole is not a problem. It is much worse that the illiterate part of the population takes everything seriously and raises a real panic. To clarify, we will go on a journey to the origins of the discovery of black holes and try to understand what it is and how to relate to it.

Invisible stars

It so happened that modern physicists describe the structure of our Universe using the theory of relativity, which Einstein carefully provided to mankind at the beginning of the 20th century. All the more mysterious are black holes, on the event horizon of which all the laws of physics we know, including Einstein's theory, cease to operate. Isn't that wonderful? In addition, the conjecture about the existence of black holes was expressed long before the birth of Einstein himself.

In 1783, there was a significant increase in scientific activity in England. In those days, science went side by side with religion, they got along well together, and scientists were no longer considered heretics. Moreover, priests were engaged in scientific research. One of these servants of God was the English pastor John Michell, who asked himself not only questions of being, but also quite scientific problems. Michell was a very titled scientist: initially he was a teacher of mathematics and ancient linguistics in one of the colleges, and after that for a number of discoveries he was admitted to the Royal Society of London.

John Michell was engaged in seismology, but in his spare time he loved to think about the eternal and space. So he got the idea that somewhere in the depths of the Universe there can exist supermassive bodies with such powerful gravity that to overcome the gravitational force of such a body it is necessary to move with a speed equal to or higher than the speed of light. If we accept such a theory as true, then even light will not be able to develop the second cosmic speed (the speed necessary to overcome the gravitational attraction of the body being left), therefore such a body will remain invisible to the naked eye.

Michell called his new theory "dark stars", and at the same time tried to calculate the mass of such objects. He expressed his thoughts on this matter in an open letter to the Royal Society of London. Unfortunately, in those days, such research was not of particular value for science, so Michell's letter was sent to the archive. Only two hundred years later, in the second half of the 20th century, it was possible to find it among thousands of other records carefully stored in the ancient library.

The first scientific justification for the existence of black holes

After the release of Einstein's General Theory of Relativity, mathematicians and physicists took seriously the solution of the equations presented by the German scientist, which should have told us a lot about the structure of the Universe. The German astronomer, physicist Karl Schwarzschild decided to do the same in 1916.

The scientist with the help of his calculations came to the conclusion that the existence of black holes is possible. He was also the first to describe what was later called the romantic phrase "event horizon" - the imaginary boundary of space-time at a black hole, after crossing which there is a point of no return. Nothing will escape from the event horizon, not even light. It is just beyond the event horizon that the so-called "singularity" occurs, where the laws of physics known to us cease to operate.

Continuing to develop his theory and solving equations, Schwarzschild discovered new secrets of black holes for himself and the world. So, he was able, exclusively on paper, to calculate the distance from the center of a black hole, where its mass is concentrated, to the event horizon. Schwarzschild called this distance the gravitational radius.

Despite the fact that mathematically Schwarzschild's solutions were exceptionally correct and could not be refuted, the scientific community of the early 20th century could not immediately accept such a shocking discovery, and the existence of black holes was written off to the level of fiction, which now and then manifested itself in the theory of relativity. For the next decade and a half, space exploration for the presence of black holes was slow, and only a few adherents of the theory of the German physicist were engaged in it.

Stars giving birth to darkness

After Einstein's equations were sorted out, it was time to use the conclusions made to understand the structure of the Universe. In particular, in the theory of stellar evolution. It's not a secret for anyone that nothing in our world lasts forever. Even stars have their own life cycle, albeit longer than a person.

One of the first scientists to become seriously interested in stellar evolution was the young astrophysicist Subramanian Chandrasekhar, a native of India. In 1930, he released a scientific paper describing the alleged internal structure of stars, as well as their life cycles.

Already at the beginning of the 20th century, scientists guessed about such a phenomenon as gravitational compression (gravitational collapse). At a certain point in its life, a star begins to contract at a tremendous speed under the influence of gravitational forces. As a rule, this happens at the moment of death of the star, but with gravitational collapse there are several ways for the further existence of the incandescent ball.

Chandrasekhar's scientific advisor Ralph Fowler - a respected theoretical physicist at one time - assumed that during gravitational collapse, any star turns into a smaller and hotter one - a white dwarf. But it turned out that the student "broke" the teacher's theory, which was shared by most physicists at the beginning of the last century. According to the young Indian's work, the demise of a star depends on its original mass. For example, only those stars whose mass did not exceed 1.44 of the mass of the Sun can become white dwarfs. This number has been called the Chandrasekhar limit. If the mass of a star exceeded this limit, then it dies in a completely different way. Under certain conditions, such a star at the time of death can be reborn into a new, neutron star - another mystery of the modern Universe. The theory of relativity, however, tells us another option - the contraction of the star to ultra-small values, and this is where the fun begins.

In 1932, an article appeared in one of the scientific journals, in which the genius physicist from the USSR Lev Landau suggested that when a supermassive star collapses, it contracts into a point with an infinitely small radius and infinite mass. Despite the fact that such an event is very difficult to imagine from the point of view of an unprepared person, Landau was not far from the truth. The physicist also suggested that according to the theory of relativity, gravity at such a point will be so great that it will begin to distort space-time.

Astrophysicists liked Landau's theory, and they continued to develop it. In 1939 in America, thanks to the efforts of two physicists - Robert Oppenheimer and Heartland Sneijder - a theory appeared that described in detail a supermassive star at the time of collapse. As a result of such an event, a real black hole should have appeared. Despite the persuasiveness of the arguments, scientists continued to deny the possibility of the existence of such bodies, as well as the transformation of stars into them. Even Einstein pulled back from this idea, believing that a star was not capable of such phenomenal transformations. Other physicists were generous in their statements, calling the possibility of such events ridiculous.
However, science always reaches the truth, you just have to wait a little. And so it happened.

The brightest objects in the universe

Our world is a collection of paradoxes. Sometimes things coexist in it, the coexistence of which defies any logic. For example, the term "black hole" will not be associated with the expression "incredibly bright" in a normal person, but the discovery of the early 60s of the last century allowed scientists to consider this statement incorrect.

With the help of telescopes, astrophysicists were able to detect previously unknown objects in the starry sky, which behaved very strangely despite the fact that they looked like ordinary stars. Studying these strange stars, American scientist Martin Schmidt drew attention to their spectrography, the data of which showed results different from those of other stars. Simply put, these stars were not like others familiar to us.

Suddenly it dawned on Schmidt, and he noticed a shift in the spectrum in the red range. It turned out that these objects are much farther from us than those stars that we are used to seeing in the sky. For example, the object observed by Schmidt was located two and a half billion light-years from our planet, but shone as brightly as a star, some hundred light-years away. It turns out that the light from one such object is comparable to the brightness of an entire galaxy. This discovery was a real breakthrough in astrophysics. The scientist named these objects "quasi-stellar" or simply "quasar".

Martin Schmidt continued to study new objects and found out that such a bright glow can be caused by only one reason - accretion. Accretion is the process of absorption of surrounding matter by a supermassive body using gravity. The scientist came to the conclusion that in the center of the quasars there is a huge black hole, which with incredible force pulls in the matter surrounding it in space. In the process of absorption of matter by the hole, the particles are accelerated to tremendous speeds and begin to glow. A kind of glowing dome around a black hole is called an accretion disk. Its visualization was well demonstrated in Christopher Nolan's Interstellar, which raised many questions, "How can a black hole glow?"

To date, scientists have found thousands of quasars in the starry sky. These strange, incredibly bright objects are called the beacons of the universe. They allow us to imagine a little better the structure of the cosmos and get closer to the moment from which it all began.

Despite the fact that astrophysicists have received circumstantial evidence of the existence of supermassive invisible objects in the Universe for many years, the term "black hole" did not exist until 1967. To avoid complicated names, American physicist John Archibald Wheeler suggested calling such objects "black holes." Why not? To some extent, they are black, because we cannot see them. In addition, they all attract, you can fall into them, just like into a real hole. And it is simply impossible to get out of such a place according to the modern laws of physics. However, Stephen Hawking claims that when traveling through a black hole you can get into another universe, another world, and this is already hope.

Fear of infinity

Due to the excessive mystery and romanticization of black holes, these objects have become a real horror story among people. The tabloid press likes to speculate on the illiteracy of the population, releasing amazing stories about how a huge black hole moves to our Earth, which will swallow the solar system in a matter of hours, or simply radiate waves of toxic gas towards our planet.

Particularly popular is the topic of destroying the planet using the Large Hadron Collider, which was built in Europe in 2006 on the territory of the European Council for Nuclear Research (CERN). The wave of panic began as someone's stupid joke, but it grew like a snowball. Someone started a rumor that a black hole could form in the collider's particle accelerator, which would swallow our planet entirely. Of course, the outraged people began to demand that experiments at the LHC be banned, fearing such an outcome of events. The European Court began to receive lawsuits demanding that the collider be closed, and the scientists who created it should be punished to the fullest extent of the law.

In fact, physicists do not deny that during a collision of particles in the Large Hadron Collider, objects similar in properties to black holes can arise, but their size is at the level of the size of elementary particles, and such "holes" exist so shortly that we even fail fix their occurrence.

One of the main experts who are trying to dispel the wave of ignorance in front of people is Stephen Hawking - the famous theoretical physicist, who, moreover, is considered a real "guru" about black holes. Hawking proved that black holes do not always absorb light that appears in accretion disks, and part of it is scattered into space. This phenomenon has been called Hawking radiation, or black hole evaporation. Hawking also established a relationship between the size of a black hole and the rate of its "evaporation" - the smaller it is, the less it exists in time. This means that all opponents of the Large Hadron Collider should not worry: black holes in it will not be able to exist even in a millionth of a second.

A theory not proven by practice

Unfortunately, the technologies of mankind at this stage of development do not allow us to test most of the theories developed by astrophysicists and other scientists. On the one hand, the existence of black holes has been pretty convincingly proven on paper and deduced using formulas that fit every variable. On the other hand, in practice, we have not yet been able to see with our own eyes a real black hole.

Despite all the disagreements, physicists suggest that in the center of each of the galaxies is a supermassive black hole, which gathers stars into clusters with its gravity and makes them travel across the Universe in a large and friendly company. In our Milky Way galaxy, according to various estimates, there are from 200 to 400 billion stars. All these stars revolve around something that has a huge mass, around something that we cannot see through a telescope. Most likely this is a black hole. Should you be afraid of her? - No, at least not in the next few billion years, but we can make another interesting film about her.

Black holes, dark matter, dark matter ... These are undoubtedly the strangest and most mysterious objects in space. Their bizarre properties can challenge the laws of physics in the universe and even the nature of existing reality. To understand what black holes are, scientists propose to “change landmarks”, learn to think outside the box and use a little imagination. Black holes are formed from the cores of super massive stars, which can be characterized as a region of space where a huge mass is concentrated in emptiness, and nothing, not even light, can escape gravitational attraction there. This is the area where the second cosmic speed exceeds the speed of light: And the more massive the object of motion, the faster it must move in order to get rid of its gravity. This is known as the second space velocity.

Collier's encyclopedia calls black holes a region in space that has arisen as a result of the complete gravitational collapse of matter, in which the gravitational attraction is so great that neither matter, nor light, nor other information carriers can leave it. Therefore, the interior of the black hole is not causally related to the rest of the universe; the physical processes occurring inside the black hole cannot influence the processes outside it. The black hole is surrounded by a surface with the property of a unidirectional membrane: matter and radiation freely fall through it into the black hole, but nothing can escape from there. This surface is called the “event horizon”.

Discovery history

Black holes predicted by general relativity (the theory of gravity proposed by Einstein in 1915) and other more modern theories of gravitation were mathematically substantiated by R. Oppenheimer and H. Snyder in 1939. But the properties of space and time in the vicinity of these objects turned out to be so unusual, that astronomers and physicists have not taken them seriously for 25 years. However, astronomical discoveries in the mid-1960s made black holes look like a possible physical reality. New discoveries and studies can fundamentally change our understanding of space and time, shedding light on billions of cosmic secrets.

Formation of black holes

While thermonuclear reactions occur in the interior of a star, they maintain high temperature and pressure, preventing the star from contracting under the influence of its own gravity. However, over time, nuclear fuel is depleted and the star begins to shrink. Calculations show that if the mass of a star does not exceed three solar masses, then it will win the “battle with gravity”: its gravitational collapse will be stopped by the pressure of “degenerate” matter, and the star will forever turn into a white dwarf or neutron star. But if the mass of a star is more than three solar masses, then nothing can stop its catastrophic collapse and it will quickly go under the event horizon, becoming a black hole.

Is the black hole a donut hole?

It is not easy to notice that which does not emit light. One way to find a black hole is to look for areas in outer space that are massive and in dark space. While searching for these types of objects, astronomers have found them in two main regions: in the centers of galaxies and in binary star systems in our Galaxy. In total, as scientists suggest, there are tens of millions of such objects.

Currently, the only reliable way to distinguish a black hole from another type of object is to measure the mass and size of the object and compare its radius with



BLACK HOLE
a region in space resulting from a complete gravitational collapse of matter, in which the gravitational attraction is so great that neither matter, nor light, nor other information carriers can leave it. Therefore, the interior of the black hole is not causally related to the rest of the universe; the physical processes taking place inside the black hole cannot influence the processes outside it. The black hole is surrounded by a surface with the property of a unidirectional membrane: matter and radiation freely fall through it into the black hole, but nothing can escape from there. This surface is called the "event horizon". Since there are still only indirect indications of the existence of black holes at distances of thousands of light years from Earth, our further presentation is based mainly on theoretical results. Black holes predicted by general relativity (the theory of gravity proposed by Einstein in 1915) and other more modern theories of gravitation were mathematically substantiated by R. Oppenheimer and H. Snyder in 1939. But the properties of space and time in the vicinity of these objects turned out to be so unusual, that astronomers and physicists have not taken them seriously for 25 years. However, astronomical discoveries in the mid-1960s made black holes look like a possible physical reality. Their discovery and study can fundamentally change our understanding of space and time.
Formation of black holes. While thermonuclear reactions occur in the interior of a star, they maintain high temperature and pressure, preventing the star from contracting under the influence of its own gravity. However, over time, nuclear fuel is depleted and the star begins to shrink. Calculations show that if the mass of a star does not exceed three solar masses, then it will win the "battle with gravity": its gravitational collapse will be stopped by the pressure of "degenerate" matter, and the star will forever turn into a white dwarf or neutron star. But if the mass of a star is more than three solar masses, then nothing can stop its catastrophic collapse and it will quickly go under the event horizon, becoming a black hole. For a spherical black hole of mass M, the event horizon forms a sphere with a circumference at the equator 2p times larger than the "gravitational radius" of the black hole RG \u003d 2GM / c2, where c is the speed of light and G is the constant of gravity. A black hole with a mass of 3 solar has a gravitational radius of 8.8 km.

If an astronomer observes a star at the moment of its transformation into a black hole, then at first he will see how the star is contracting faster and faster, but as its surface approaches the gravitational radius, the compression will begin to slow down until it stops completely. In this case, the light coming from the star will fade and turn red until it goes out completely. This is because in the struggle with the gigantic force of gravity, light loses energy and it takes more and more time for it to reach the observer. When the surface of the star reaches the gravitational radius, the light that leaves it will take an infinite time to reach the observer (and in this case the photons will completely lose their energy). Consequently, the astronomer will never wait for this moment, much less see what is happening to the star under the event horizon. But theoretically, this process can be investigated. The calculation of the idealized spherical collapse shows that in a short time the star is compressed to a point where infinitely large values \u200b\u200bof density and gravity are achieved. This point is called "singularity". Moreover, general mathematical analysis shows that if an event horizon has arisen, then even a nonspherical collapse leads to a singularity. However, all this is true only if general relativity is applicable down to very small spatial scales, which we are not yet sure of. In the microcosm, quantum laws operate, and the quantum theory of gravity has not yet been created. It is clear that quantum effects cannot stop a star from collapsing into a black hole, but they could prevent the appearance of a singularity. The modern theory of stellar evolution and our knowledge of the stellar population of the Galaxy indicate that among its 100 billion stars there should be about 100 million black holes formed during the collapse of the most massive stars. In addition, very large black holes can be found in the cores of large galaxies, including ours. As already noted, in our era, only a mass more than three times the solar mass can become a black hole. However, immediately after the Big Bang, from which approx. 15 billion years ago, the expansion of the Universe began, black holes of any mass could be born. The smallest of them, due to quantum effects, had to evaporate, losing their mass in the form of radiation and particle flows. But "primordial black holes" with a mass of more than 1015 g could have survived to this day. All calculations of stellar collapse are made under the assumption of a slight deviation from spherical symmetry and show that the event horizon is always formed. However, with a strong deviation from spherical symmetry, the collapse of a star can lead to the formation of a region with infinitely strong gravity, but not surrounded by an event horizon; it is called "naked singularity". This is no longer a black hole in the sense we discussed above. The physical laws near a bare singularity can have a very unexpected form. Currently, a naked singularity is considered an unlikely object, while most astrophysicists believe in the existence of black holes.
Properties of black holes. To an outside observer, the structure of a black hole looks extremely simple. During the collapse of a star into a black hole in a small fraction of a second (according to the clock of a distant observer), all its external features associated with the inhomogeneity of the original star are emitted in the form of gravitational and electromagnetic waves. The resulting stationary black hole "forgets" all information about the original star, except for three quantities: total mass, angular momentum (associated with rotation) and electric charge. By studying a black hole, it is no longer possible to know whether the original star consisted of matter or antimatter, whether it had the shape of a cigar or a pancake, etc. Under real astrophysical conditions, a charged black hole will attract particles of the opposite sign from the interstellar medium, and its charge will quickly become zero. The remaining stationary object will either be a non-rotating "Schwarzschild black hole", which is characterized only by mass, or a rotating "Kerr black hole", which is characterized by mass and angular momentum. The uniqueness of the above types of stationary black holes was proved within the framework of general relativity by W. Israel, B. Carter, S. Hawking, and D. Robinson. According to general relativity, space and time are curved by the gravitational field of massive bodies, with the greatest curvature occurring near black holes. When physicists talk about intervals of time and space, they mean numbers read from some kind of physical clock and rulers. For example, a molecule with a certain vibration frequency can play the role of a clock, the number of which between two events can be called a "time interval". It is remarkable that gravity acts on all physical systems in the same way: all clocks show that time is slowing down, and all rulers show that space is stretching near a black hole. This means that the black hole bends the geometry of space and time around itself. Far from the black hole, this curvature is small, but near it is so great that the rays of light can move around it in a circle. Far from the black hole, its gravitational field is exactly described by Newton's theory for a body of the same mass, but near the black hole gravity becomes much stronger than Newton's theory predicts. Any body falling on a black hole, long before crossing the event horizon, will be torn apart by powerful tidal gravitational forces arising from the difference in attraction at different distances from the center. A black hole is always ready to absorb matter or radiation, thereby increasing its mass. Its interaction with the outside world is determined by a simple Hawking principle: the area of \u200b\u200bthe event horizon of a black hole never decreases, if one does not take into account the quantum creation of particles. J. Bekenstein in 1973 suggested that black holes obey the same physical laws as physical bodies emitting and absorbing radiation (the "absolutely black body" model). Under the influence of this idea, Hawking showed in 1974 that black holes can emit matter and radiation, but this will be noticeable only if the mass of the black hole itself is relatively small. Such black holes could be born immediately after the Big Bang, from which the expansion of the Universe began. The masses of these primordial black holes should be no more than 1015 g (like a small asteroid), and a size of 10-15 m (like a proton or neutron). The powerful gravitational field near the black hole creates particle-antiparticle pairs; one of the particles of each pair is absorbed by the hole, and the second is emitted outside. A black hole with a mass of 1015 g should behave like a body with a temperature of 1011 K. The idea of \u200b\u200b"evaporation" of black holes completely contradicts the classical idea of \u200b\u200bthem as bodies incapable of radiating.
Search for black holes. Calculations within the framework of Einstein's general theory of relativity indicate only the possibility of the existence of black holes, but by no means prove their presence in the real world; the discovery of a real black hole would be an important step in the development of physics. Finding isolated black holes in space is hopelessly difficult: we won't be able to spot a small, dark object against a backdrop of cosmic blackness. But there is hope to detect a black hole by its interaction with the surrounding astronomical bodies, by its characteristic influence on them. Supermassive black holes can be located in the centers of galaxies, continuously devouring stars there. Concentrating around the black hole, the stars should form central brightness peaks in the galactic cores; their search is now underway. Another search method is to measure the speed of stars and gas around a central object in the galaxy. If their distance from the central object is known, then its mass and average density can be calculated. If it significantly exceeds the density possible for star clusters, then it is believed to be a black hole. In this way, in 1996, J. Moran and colleagues determined that in the center of the galaxy NGC 4258 there is probably a black hole with a mass of 40 million solar. The most promising is the search for a black hole in binary systems, where it, together with a normal star, can revolve around a common center of mass. From the periodic Doppler shift of the lines in the spectrum of the star, one can understand that it is paired with a certain body and even estimate the mass of the latter. If this mass exceeds 3 solar masses, and it is not possible to notice the radiation of the body itself, then it is very possible that this is a black hole. In a compact binary system, a black hole can trap gas from the surface of a normal star. Orbiting the black hole, this gas forms a disk and, as it spirals closer to the black hole, heats up strongly and becomes a source of powerful X-ray radiation. Rapid fluctuations of this radiation should indicate that the gas is rapidly moving in a small-radius orbit around the tiny massive object. Since the 1970s, several X-ray sources have been discovered in binary systems with clear indications of the presence of black holes. The most promising is the X-ray binary V 404 Cygnus, the mass of the invisible component of which is estimated at no less than 6 solar masses. Other notable black hole candidates are found in the binary X-ray systems Cygnus X-1, LMCX-3, V 616 Unicorn, QZ Chanterelles, and the X-ray novae Ophiuchus 1977, Fly 1981, and Scorpio 1994. With the exception of LMCX-3, located in the Large Magellanic Cloud, they are all located in our Galaxy at distances of about 8000 sv. years from Earth.
see also
COSMOLOGY;
GRAVITY;
GRAVITY COLLAPSE;
RELATIVITY;
EXTRA ATMOSPHERIC ASTRONOMY.
LITERATURE
Cherepashchuk A.M. Black hole masses in binary systems. Advances in Physical Sciences, vol. 166, p. 809, 1996

Collier's Encyclopedia. - Open Society. 2000 .

Synonyms:

See what "BLACK HOLE" is in other dictionaries:

BLACK HOLE, a localized area of \u200b\u200bouter space from which neither matter nor radiation can escape, in other words, the first cosmic speed exceeds the speed of light. The boundary of this area is called the event horizon. ... ... Scientific and technical encyclopedic dictionary

Cosmich. an object resulting from the compression of the body of gravity. forces to sizes smaller than its gravitational radius rg \u003d 2g / c2 (where M is the body mass, G is a gravitational constant, with the numerical value of the speed of light). Prediction of existence in ... ... Physical encyclopedia

Mysterious and elusive black holes. The laws of physics confirm the possibility of their existence in the universe, but many questions still remain. Numerous observations show that holes exist in the universe and there are more than a million of these objects.

What are black holes?

Back in 1915, when solving Einstein's equations, such a phenomenon as "black holes" was predicted. However, the scientific community became interested in them only in 1967. They were then called "collapsed stars", "frozen stars".

Now a black hole is called a region of time and space, which have such gravity that even a beam of light cannot get out of it.

How do black holes form?

There are several theories of the appearance of black holes, which are divided into hypothetical and realistic. The simplest and most widespread realistic theory is the theory of gravitational callapse of large stars.

When a sufficiently massive star before "death" grows in size and becomes unstable, consuming the last fuel. At the same time, the mass of the star remains unchanged, but its size decreases as the so-called compaction occurs. In other words, during compaction, the heavy core "falls" into itself. In parallel with this, the compaction leads to a sharp increase in temperature inside the star and the outer layers of the celestial body are torn off, from which new stars are formed. At the same time in the center of the star - the core falls into its own "center". As a result of the action of the forces of gravity, the center collapses into a point - that is, the forces of gravity are so strong that they absorb the compacted core. So a black hole is born, which begins to distort space and time, so that even light cannot escape from it.

At the centers of all galaxies is a supermassive black hole. According to Einstein's theory of relativity:

"Any mass distorts space and time."

Now imagine how strongly a black hole distorts time and space, because its mass is huge and at the same time squeezed into an ultra-small volume. This ability creates the following oddity:

“Black holes have the ability to practically stop time and compress space. Because of this extreme distortion, the holes become invisible to us. "

If black holes are not visible, how do we know they exist?

Yes, even though the black hole is invisible, but it should be noticeable due to the matter that falls into it. And also the stellar gas, which is attracted by the black hole, when approaching the event horizon, the gas temperature begins to rise to superhigh values, which leads to a glow. This is why black holes glow. Thanks to this, albeit weak, glow, astronomers and astrophysicists explain the presence in the center of the galaxy of an object with a small volume, but a huge mass. At the moment, as a result of observations, about 1000 objects have been discovered that are similar in behavior to black holes.

Black holes and galaxies

How can black holes affect galaxies? This question plagues scientists around the world. There is a hypothesis according to which it is the black holes located in the center of the galaxy that affect its shape and evolution. And that when two galaxies collide, black holes merge and during this process such a huge amount of energy and matter is ejected that new stars are formed.

Types of black holes

• According to the existing theory, there are three types of black holes: stellar, supermassive, miniature. And each of them was formed in a special way.
• - Black holes of stellar masses, it grows to enormous sizes and collapses.
  - Supermassive black holes, which can have a mass equivalent to millions of Suns, are likely to exist in the centers of almost all galaxies, including our Milky Way. Scientists still have different hypotheses for the formation of supermassive black holes. So far, only one thing is known - supermassive black holes are a by-product of the formation of galaxies. Supermassive black holes - they differ from ordinary ones in that they are very large in size, but paradoxically low in density.
• - No one has yet been able to find a miniature black hole that would have a mass less than the Sun. It is possible that miniature holes could have formed shortly after the "Big Bang", which is the initial exact existence of our universe (about 13.7 billion years ago).
• - More recently, a new concept has been introduced as "white black holes". This is still a hypothetical black hole, which is the opposite of a black hole. Stephen Hawking actively studied the possibility of the existence of white holes.
• - Quantum black holes - they exist only in theory. Quantum black holes can form when ultra-small particles collide in a nuclear reaction.
• - Primordial black holes are also a theory. They were formed immediately after emergence.

At the moment, there are many open questions that future generations have yet to answer. For example, can there really exist so-called "wormholes" with which you can travel through space and time. What exactly happens inside a black hole and what laws do these phenomena obey. And what about the disappearance of information in a black hole?