Black hole in space: where does it come from?

A black hole as imagined by an artist

Due to the relatively recent increase in interest in creating popular science films on the topic of space exploration, modern viewers have heard a lot about phenomena such as the singularity, antigravity, dark matter or black hole. However, movies obviously do not reveal the full nature of these phenomena, and sometimes even distort the constructed scientific theories for greater effect. For this reason, the understanding of many modern people about these phenomena is either completely superficial or completely erroneous. One of the solutions to the problem that has arisen is this article, in which we will try to understand the existing research results and answer the question - what is a black hole?

The emergence of black hole theory

In 1784, the English priest and naturalist John Michell first mentioned in a letter to the Royal Society a certain hypothetical massive body that has such a strong gravitational attraction that its second escape velocity will exceed the speed of light. The second escape velocity is the speed that a relatively small object will need to overcome the gravitational attraction of a celestial body and go beyond the closed orbit around this body. According to his calculations, a body with the density of the Sun and a radius of 500 solar radii will have a second cosmic velocity on its surface equal to the speed of light. In this case, even light will not leave the surface of such a body, and therefore this body will only absorb the incoming light and will remain invisible to the observer - a kind of black spot against the background of dark space.

However, Michell's concept of a supermassive body did not attract much interest until the work of Einstein. Let us recall that the latter defined the speed of light as the maximum speed of information transfer. In addition, Einstein expanded the theory of gravity to speeds close to the speed of light (GR). As a result, it was no longer relevant to apply Newtonian theory to black holes.

ChSV, what does it mean in youth?

People who have an inflated sense of self-importance are characterized by the following character traits:

They constantly interfere in the conversation and interrupt
They often make fun of people, showing them not at their best, drawing attention to their shortcomings
Constantly trying to express their own point of view, and show themselves to be cool, or indicate superiority

ChSV, which means in youth:

Without a sense of self-importance it is impossible to develop. Our society is built in such a way that people strive to be better than they really are, so sometimes they do things they don’t like in order to gain recognition from others.
As a result of this, a person can achieve great success. When an individual realizes that he has achieved everything he wanted, he is bursting with pride in himself, as well as a sense of self-importance.
Sometimes this situation continues, and the person becomes overly arrogant and begins to suffer from delusions of grandeur. Unfortunately, in most cases, a sense of self-importance turns out to be completely unnecessary, as it sometimes interferes with life.

Crown on head

Interactive black hole model (opens in a new window)

Einstein's equation

As a result of applying general relativity to black holes and solving Einstein's equations, the main parameters of a black hole were identified, of which there are only three: mass, electric charge and angular momentum. It is worth noting the significant contribution of the Indian astrophysicist Subramanian Chandrasekhar, who created the fundamental monograph: “Mathematical Theory of Black Holes.”

Thus, the solution to Einstein’s equations is presented in four options for four possible types of black holes:

BH without rotation and without charge – Schwarzschild solution. One of the first descriptions of a black hole (1916) using Einstein’s equations, but without taking into account two of the three parameters of the body. The solution of the German physicist Karl Schwarzschild allows one to calculate the external gravitational field of a spherical massive body. The peculiarity of the concept of black holes of the German scientist is the presence of an event horizon and the singularity hiding behind it. Schwarzschild was also the first to calculate the gravitational radius, which received his name, which determines the radius of the sphere on which the event horizon would be located for a body with a given mass.
BH without rotation with charge – Reisner-Nordström solution. A solution put forward in 1916-1918, taking into account the possible electric charge of a black hole. This charge cannot be arbitrarily large and is limited due to the resulting electrical repulsion. The latter must be compensated by gravitational attraction.
BH with rotation and without charge - Kerr's solution (1963). A rotating Kerr black hole differs from a static one by the presence of a so-called ergosphere (read more about this and other components of a black hole).
BH with rotation and charge - Kerr-Newman solution. This solution was calculated in 1965 and is currently the most complete, since it takes into account all three parameters of the black hole. However, it is still assumed that in nature black holes have an insignificant charge.

Frequency detectors. Operating principles and diagrams of black holes. Distortion of signals in black holes

10 Frequency detectors

10.1 Definition, purpose, classification and main parameters of black hole

Definition

– BH is a device that performs one of 2 functions:

– conversion of HF voltage modulated by frequency into LF voltage changing according to the modulation law;

– converting the deviation of the carrier frequency of the signal from its nominal value into a constant voltage, the magnitude and sign of which characterize the magnitude and sign of this deviation.

The first function is performed by CH demodulators; they are part of the FM signal control system.

The first function is performed by H discriminators - they are part of the AFC systems and generate control voltage.

Classification:

Based on the type of signal conversion, BH are divided into

– frequency-amplitude – frequency changes are converted into amplitude changes with subsequent detection in AD4

– frequency-phase – the frequency deviation is converted into deviations between the vectors of the main and auxiliary voltages, followed by detection in the PD;

– pulse-frequency – convert the FM signal into a sequence of pulses, the repetition frequency of which is proportional to the deviation of the input frequency from the average value. LF voltage proportional to the number of pulses per unit time can be obtained using pulse counters;

– autocorrelation black holes;

– BH based on PAP (synchronous phase detectors);

– Digital black holes.

Main parameters:

1. frequency or detector characteristic - the dependence of the output voltage on frequency is shown in Fig. 10.1.

Fig. 10.1.

Here ω0 is the transition frequency of the black hole. Parameters that describe the characteristic: slope (1) and frequency range of the frequency response - the frequency interval lying between the humps of the frequency characteristic (approximately we can consider the frequency characteristic = (2). The working area is located between the humps.

Requirements for detector characteristics of BH:

– the RF solution must correspond to the range of frequency deviations that are possible for a given signal in a given receiver;

– within the limits of the frequency detector characteristic d.b. perhaps more linear;

– for given PChD and f0, the slope SChD d.b. possibly larger;

– transition frequency f0 d.b. quite stable.

In the case of a BH demodulator, the most important thing is the linearity of the characteristic within the BH (min. Distortion) with a larger opening - greater than the maximum frequency deviation. Requirements for frequency slope and stability can be relaxed.

In the case of a black hole discriminator, the most important requirement is frequency stability, because in AFC systems, frequency instability will be transferred to the adjusted frequencies, and the symmetry of the characteristic with respect to f0 and greater steepness is also important, because near zero, the instability of the UPT is great.

2. Coeff. voltage transmission (1);

3. Signal distortion – nonlinear, linear (frequency and phase);

4. Input impedance;

5. Coefficient RF voltage filtering.

10.2 Operating principles and diagrams of black holes

As a rule, an AO is placed at the input of the black hole to remove parasitic AM. AO is a mandatory element of the FM signal receiver path.

1. Frequency-amplitude detectors (FAD) (FR on detuned circuits)

The operating principle is based on supplying an input signal to the inclined section of the resonant characteristic. As a resonant system, it could be any frequency-dependent circuit is used - LC circuits, RC filters, active RC filters, microstrip filters, piezo, mechanical, ceramic filters, etc.

Figure 10.2 shows the work schedule.

Fig. 10.2.

As a rule, balanced circuits are used. The diagram of a balanced black hole with 2 detuned circuits is shown in Fig. 10.3.

Fig10.3.

Here the currents through D1 and D2 flow in the opposite direction, and the output voltage is (2).

The detector characteristic of such a black hole is obtained from the interaction of two characteristics of detuned circuits.

Fig. 10.4.

If the parameters of the circuits and diodes are the same, then the detector characteristic equation will be (1). Here ξ is the current detuning, and ξ0 is the detuning at zero frequency deviation (2).

Slope of the detector characteristic at ξ=0 (3). The analysis shows that the maximum value of the slope is achieved at ξ=1/√2. However, the lowest degree of nonlinear distortion is achieved at ξ=1/√1.5.

2. Frequency-phase detectors (FPD)

In practice, BHs with FM–PM conversion followed by detection in PD are widely used. Compared to black holes on detuned circuits, they are easier to tune. Before such a black hole, a joint stock company is required.

Block diagram Fig. 10.5.

Fig. 10.5.

Schematic diagram of a diode PFD in Fig. 10.6.

Fig. 10.6.

Here a choke is needed to close the direct current of the diodes. Then a voltage of the form (4) is applied to each diode. With a change in the signal frequency relative to the resonant frequencies of the circuits (fo), the phase shift between the EMF induced in the 2nd circuit and the current in the 2nd circuit changes, which leads to a change in the voltage on the diodes and at the output, which is determined by (5).

When fc=fo the circuits have purely active resistance and (6).

At fc

When fc>fo – capacitive.

As a result, when the frequency at the input changes, the output voltage forms the required detector characteristic, as in Fig. 10.1.

The absence of an AO at the input will lead to the transfer of parasitic AM to the voltage at the output of the PFD.

A type of PFD that does not require an AO at the input is a fractional detector or a ratio detector.

The diagram of such a detector is shown in Fig. 10.7.

Fig. 10.7.

Its characteristic feature is the presence of inertial circuits connected in parallel to the detector. This makes it insensitive to spurious AM input signal (with a certain frequency).

Since post. The time is selected from (7), then during the modulation period the voltage on the circuit does not change significantly and an auto-bias of a constant value is formed on each diode, which changes the cutoff angle and changes Rinput. Increased angle - smaller R input and stronger shunting of the circuit - Ku decreases - voltage decreases - angle increases and vice versa.

Such a detector acts as a diode limiter with a fixed threshold - it does not require a separate AO.

3. Promising are D. without inductance - autocorrelation BH. They are built on SAW delay lines.

The diagram of such a detector is shown in Fig. 10.8.

Fig. 10.8.

Here, the shaper converts the input signal into pulses with varying frequency and duration. Phase shift (1), where k is the number of periods.

Advantages:

– well suited for micro execution;

Black hole formation

First direct visual image of the supermassive black hole and its shadow at the center of the M87 galaxy

There are several theories about how a black hole forms and appears, the most famous of which is that it arises as a result of the gravitational collapse of a star with sufficient mass. Such compression can end the evolution of stars with a mass of more than three solar masses. Upon completion of thermonuclear reactions inside such stars, they begin to rapidly compress into a super-dense neutron star. If the gas pressure of a neutron star cannot compensate for gravitational forces, that is, the mass of the star overcomes the so-called. Oppenheimer-Volkoff limit, then the collapse continues, resulting in matter being compressed into a black hole.

The second scenario describing the birth of a black hole is the compression of protogalactic gas, that is, interstellar gas at the stage of transformation into a galaxy or some kind of cluster. If there is insufficient internal pressure to compensate for the same gravitational forces, a black hole may arise.

Two other scenarios remain hypothetical:

The emergence of a black hole as a result of the Big Bang - the so-called. primordial black holes.
Occurrence as a result of nuclear reactions occurring at high energies. An example of such reactions is experiments at colliders.

How to make a VP

Mutual PR on VKontakte can be divided into two types:

between communities;
between personal pages of users.

And although the essence of these processes is the same, the actions are still different. So let's look at each type separately.

Between groups

For mutual PR to be free and bring only joy to everyone, it is necessary that the coverage of VP groups be approximately equal. It is unlikely that the admin of a public page with a reach of 10,000 people will agree to mutual PR with a group that has a reach of only 1,000. And if he does agree, it will only be with an additional payment.

You need to pay attention specifically to the reach of the community, and not to the number of subscribers. It is this indicator that allows you to find out how many people will actually see a post with your advertisement.

I’ll say a trivial thing: the smaller the coverage in the group with which you plan to do mutual PR, the fewer people will see your post and move to your community. This means that in order to gain any significant number of subscribers, you will need to look for more groups for VPs and spend more time on it. It is optimal to engage in mutual PR if you have at least 2,000–3,000 active participants in the community.

Some admins resort to a “trick” - they recruit participants into their public pages, and then do mutual PR. Never do this! Cheating does take place, but only in the first stages of public development and if you buy advertising and not do VP. News spreads very quickly in admin circles. If you are caught cheating, then no one will want to do business with you in the future.

Another important point is that for mutual PR you should select groups similar in topic to yours. Of course, no one forbids a public page with recipes from being promoted in a group dedicated to cars. But the benefits of such an event will be doubtful. It is unlikely that car enthusiasts will go to read posts about how to prepare diet cheesecakes with strawberries.

More than 100 cool lessons, tests and exercises for brain development

Start developing

How to find a group for a VP

The simplest and most obvious option is to go to the VKontakte search and find a suitable community for your topic. Select a public page that roughly matches yours in terms of coverage and write a message to the administrator. Write to the point. It would be ideal if you immediately send a link to your community, information about the target audience and a screenshot of statistics.

On a note. In business correspondence, it is not customary to send many short messages. It’s better to compose a competent text and send it right away. To do this, use a line break and separate paragraphs from each other.

Groups can be searched on the VKontakte advertising exchanges. Of course, administrators first add their projects to exchanges to find advertisers. But many of them will not be against the VP. You just need to choose a public page that will match your level.

You can also try to find VKontakte communities where VPshers gather. I personally don't like this method at all. Recently, it is almost impossible to find a normal community for VPs in such groups. You can, of course, spend a lot of time and find something worthwhile, but the efficiency of such an event will tend to zero.

Between people

Mutual PR of personal pages is just one way to make a lot of friends. Some do this to gather an audience, while others stroke their ego. I discussed this method in detail in an article about making friends on Odnoklassniki. On VKontakte this is done in exactly the same way.

Enter the search query “add as a friend”, “mutual PR” or something similar. Go to several communities. There will be a huge number of posts on the wall from people who want to make friends. Add them as friends, and then publish a post yourself inviting them to join you. That's all mutual PR between people.

Structure and physics of black holes

The structure of a black hole according to Schwarzschild includes only two elements that were mentioned earlier: the singularity and the event horizon of the black hole. Briefly speaking about the singularity, it can be noted that it is impossible to draw a straight line through it, and also that most existing physical theories do not work inside it. Thus, the physics of the singularity remains a mystery to scientists today. The event horizon of a black hole is a certain boundary, crossing which a physical object loses the opportunity to return back beyond its limits and will definitely “fall” into the singularity of the black hole.

Realistic concept of an accretion disk around a supermassive black hole

The structure of a black hole becomes somewhat more complicated in the case of the Kerr solution, namely in the presence of rotation of the black hole. Kerr's solution assumes that the hole has an ergosphere. The ergosphere is a certain region located outside the event horizon, inside which all bodies move in the direction of rotation of the black hole. This area is not yet exciting and it is possible to leave it, unlike the event horizon. The ergosphere is probably some kind of analogue of an accretion disk, representing rotating matter around massive bodies. If a static Schwarzschild black hole is represented as a black sphere, then the Kerry black hole, due to the presence of an ergosphere, has the shape of an oblate ellipsoid, in the form of which we often saw black holes in drawings, in old movies or video games.

Let us next consider some properties of black holes, which are often of interest to the reader:

How much does a black hole weigh? – The most theoretical material on the emergence of a black hole is available for the scenario of its appearance as a result of the collapse of a star. In this case, the maximum mass of a neutron star and the minimum mass of a black hole are determined by the Oppenheimer-Volkov limit, according to which the lower limit of the mass of a black hole is 2.5 - 3 solar masses. The heaviest black hole that has been discovered (in the galaxy NGC 4889) has a mass of 21 billion solar masses. However, we should not forget about black holes that hypothetically arise as a result of nuclear reactions at high energies, such as those at colliders. The mass of such quantum black holes, in other words “Planck black holes,” is of the order of the Planck mass, namely 2·10−5g.
Black hole size. The minimum radius of a black hole can be calculated from the minimum mass (2.5 – 3 solar masses). If the gravitational radius of the Sun, that is, the area where the event horizon would be located, is about 2.95 km, then the minimum radius of a black hole of 3 solar masses will be about nine kilometers. Such relatively small sizes are hard to comprehend when we are talking about massive objects that attract everything around them. However, for quantum black holes the radius is equal to the Planck length - 10−35 m.
The average density of a black hole depends on two parameters: mass and radius. The density of a black hole with a mass of about three solar masses is about 6·1026 kg/m³, while the density of water is 1000 kg/m³. However, such small black holes have not been found by scientists. Most detected black holes have a mass greater than 105 solar masses. There is an interesting pattern according to which the more massive the black hole, the lower its density. In this case, a change in mass by 11 orders of magnitude entails a change in density by 22 orders of magnitude. Thus, a black hole with a mass of 1·109 solar masses has a density of 18.5 kg/m³, which is one less than the density of gold. And black holes with a mass of more than 1010 solar masses can have an average density less than that of air. Based on these calculations, it is logical to assume that the formation of a black hole does not occur due to compression of matter, but as a result of the accumulation of a large amount of matter in a certain volume. In the case of quantum black holes, their density can be about 1094 kg/m³.
The temperature of a black hole also depends inversely on its mass. This temperature is directly related to Hawking radiation. The spectrum of this radiation coincides with the spectrum of an absolutely black body, that is, a body that absorbs all incident radiation. The radiation spectrum of an absolutely black body depends only on its temperature, then the temperature of the black hole can be determined from the Hawking radiation spectrum. As mentioned above, this radiation is more powerful the smaller the black hole. At the same time, Hawking radiation remains hypothetical, since it has not yet been observed by astronomers. It follows from this that if Hawking radiation exists, then the temperature of the observed black holes is so low that it does not allow this radiation to be detected. According to calculations, even the temperature of a hole with a mass on the order of the mass of the Sun is negligibly small (1·10-7K or -272°C). The temperature of quantum black holes can reach about 1012 K, and with their rapid evaporation (about 1.5 minutes), such black holes can emit the energy of about ten million atomic bombs. But, fortunately, to create such hypothetical objects would require energy 1014 times greater than that achieved today at the Large Hadron Collider. In addition, such phenomena have never been observed by astronomers.

What does a black hole consist of?

Another question worries both scientists and those who are simply interested in astrophysics - what does a black hole consist of? There is no clear answer to this question, since it is not possible to look beyond the event horizon surrounding any black hole. In addition, as mentioned earlier, theoretical models of a black hole provide for only 3 of its components: the ergosphere, the event horizon and the singularity. It is logical to assume that in the ergosphere there are only those objects that were attracted by the black hole and that now revolve around it - various kinds of cosmic bodies and cosmic gas. The event horizon is only a thin implicit boundary, once beyond which the same cosmic bodies are irrevocably attracted towards the last main component of the black hole - the singularity. The nature of the singularity has not been studied today and it is too early to talk about its composition.

According to some assumptions, a black hole may consist of neutrons. If we follow the scenario of the occurrence of a black hole as a result of the compression of a star to a neutron star with its subsequent compression, then probably the main part of the black hole consists of neutrons, of which the neutron star itself is composed. In simple terms: when a star collapses, its atoms are compressed in such a way that electrons combine with protons, thereby forming neutrons. A similar reaction actually occurs in nature, and with the formation of a neutron, neutrino radiation occurs. However, these are just assumptions.

What does ChSV mean for young people in VK?

Although this is an internet meme, the problem has deeper roots. This abbreviation was often used by Carlos Castaneda in his works. People of the older generation have no idea what ChSV is, since the abbreviation appeared several years ago. Recently it has become quite popular in games, Duty, Minecraft, and also in some social networks. People don't use this abbreviation very often at all. What does ChSV VKontakte mean?

What does ChSV mean to young people in VK:

As mentioned above, VKontakte is a kind of meme, which means that a person has a very high self-esteem. Accordingly, it is almost impossible to prove anything to him, or to prove that you are right, since the only correct option is the one proposed by him.
Psychologists say that FSN is not just a meme, or one of the character traits. This can cause a lot of anxiety, as well as problems in communicating with students, peers and parents.
Such people are usually very arrogant, arrogant, emotional, and will always prove that they are right. Such teenagers have many problems with teachers because they do not want to admit their mistakes.

The youth

What happens if you fall into a black hole?

Spaghettification

Falling into an astrophysical black hole causes the body to stretch. Consider a hypothetical suicide cosmonaut who heads into a black hole wearing only a spacesuit, feet first. Crossing the event horizon, the astronaut will not notice any changes, despite the fact that he no longer has the opportunity to get back. At some point, the astronaut will reach a point (slightly behind the event horizon) at which deformation of his body will begin to occur. Since the gravitational field of a black hole is non-uniform and is represented by a force gradient increasing towards the center, the astronaut’s legs will be subject to a noticeably greater gravitational influence than, for example, the head. Then, due to gravity, or rather tidal forces, the legs will “fall” faster. Thus, the body begins to gradually elongate in length. To describe this phenomenon, astrophysicists have come up with a rather creative term - spaghettification. Further stretching of the body will probably decompose it into atoms, which, sooner or later, will reach a singularity. One can only guess how a person will feel in this situation. It is worth noting that the effect of stretching a body is inversely proportional to the mass of the black hole. That is, if a black hole with the mass of three Suns instantly stretches/tears the body, then the supermassive black hole will have lower tidal forces and there are suggestions that some physical materials could “tolerate” such deformation without losing their structure.

As you know, time flows slower near massive objects, which means time for a suicide bomber astronaut will flow much slower than for earthlings. In this case, perhaps he will outlive not only his friends, but also the Earth itself. To determine how much time will slow down for an astronaut, calculations will be required, but from the above it can be assumed that the astronaut will fall into the black hole very slowly and, perhaps, simply will not live to see the moment when his body begins to deform.

It is noteworthy that for an observer from the outside, all bodies that fly up to the event horizon will remain at the edge of this horizon until their image disappears. The reason for this phenomenon is gravitational redshift. Simplifying somewhat, we can say that the light falling on the body of a suicide cosmonaut “frozen” at the event horizon will change its frequency due to its slowed down time. As time passes more slowly, the frequency of light will decrease and the wavelength will increase. As a result of this phenomenon, at the output, that is, for an external observer, the light will gradually shift towards low frequency - red. A shift of light along the spectrum will take place, as the suicide cosmonaut moves further and further away from the observer, although almost imperceptibly, and his time flows more and more slowly. Thus, the light reflected by his body will soon go beyond the visible spectrum (the image will disappear), and in the future the astronaut’s body can be detected only in the region of infrared radiation, later in radio frequency, and as a result the radiation will be completely elusive.

Despite the above, it is assumed that in very large supermassive black holes, tidal forces do not change so much with distance and act almost uniformly on the falling body. In this case, the falling spacecraft would retain its structure. A reasonable question arises: where does the black hole lead? This question can be answered by the work of some scientists, linking two phenomena such as wormholes and black holes.

Back in 1935, Albert Einstein and Nathan Rosen, taking into account the general theory of relativity, hypothesized the existence of so-called wormholes, connecting two points of space-time through places of significant curvature of the latter - an Einstein-Rosen bridge or wormhole. For such a powerful curvature of space, bodies with gigantic mass would be required, the role of which would be perfectly fulfilled by black holes.

The Einstein-Rosen Bridge is considered an impassable wormhole because it is small in size and unstable.

A traversable wormhole is possible within the framework of the theory of black and white holes. Where the white hole is the output of information trapped in the black hole. The white hole is described within the framework of general relativity, but today remains hypothetical and has not been discovered. Another model of a wormhole was proposed by American scientists Kip Thorne and his graduate student Mike Morris, which can be passable. However, both in the case of the Morris-Thorn wormhole and in the case of black and white holes, the possibility of travel requires the existence of so-called exotic matter, which has negative energy and also remains hypothetical.

The real Denis Vysotsky on Instagram and contact

Denis Vysotsky's contact page is available in only one copy: vk.com/den11111111. All accounts, except the official one, belong to scammers who profit from the reputation of a clairvoyant.

The notes on the wall will tell fans of the clairvoyant about his personal life and reveal details of Vysotsky’s worldview.

Denis Vysotsky’s Instagram contains many personal photos and shots from the filming of the Battle of Psychics. He often posts photographs with psychics known from previous seasons of the project. For example, there is a scandalous photo with, which the yellow media inflated into a novel.

Despite the fact that Vysotsky does not conduct receptions, his name has become popular among scammers. Those who want to get a consultation with one of the participants in the Battle of Psychics should remember that real magicians do not take advance payments and do not consult online.

Black holes in the Universe

The existence of black holes was confirmed relatively recently (September 2015), but before that time there was already a lot of theoretical material on the nature of black holes, as well as many candidate objects for the role of a black hole. First of all, you should take into account the size of the black hole, since the very nature of the phenomenon depends on them:

Stellar mass black hole . Such objects are formed as a result of the collapse of a star. As mentioned earlier, the minimum mass of a body capable of forming such a black hole is 2.5 - 3 solar masses.
Intermediate mass black holes . A conditional intermediate type of black hole that has grown due to the absorption of nearby objects, such as a cluster of gas, a neighboring star (in systems of two stars) and other cosmic bodies.
Supermassive black hole . Compact objects with 105-1010 solar masses. The distinctive properties of such black holes are their paradoxically low density, as well as weak tidal forces, which were mentioned earlier. This is exactly the supermassive black hole at the center of our Milky Way galaxy (Sagittarius A*, Sgr A*), as well as most other galaxies.

Candidates for the ChD

BH candidate A0620-00 (V616 Monoceros) is a double star in the constellation Monoceros at a distance of 3000 light years. years from the Sun.

The nearest black hole, or rather a candidate for the role of a black hole, is object A0620-00 (V616 Monoceros), which is located at a distance of 3000 light years from the Sun (in our galaxy). It consists of two components: a main sequence star with a mass of half the solar mass, as well as an invisible small body whose mass is 3–5 solar masses. If this object turns out to be a small black hole of stellar mass, then it will rightfully become the nearest black hole.

X-ray image of Cygnus X-1

Following this object, the second closest black hole is the object Cygnus X-1 (Cyg X-1), which was the first candidate for the role of a black hole. The distance to it is approximately 6070 light years. Quite well studied: it has a mass of 14.8 solar masses and an event horizon radius of about 26 km.

According to some sources, another closest candidate for the role of a black hole may be a body in the star system V4641 Sagittarii (V4641 Sgr), which, according to estimates in 1999, was located at a distance of 1600 light years. However, subsequent studies have increased this distance by at least 15 times.

How many black holes are there in our galaxy?

There is no exact answer to this question, since observing them is quite difficult, and over the entire period of studying the sky, scientists have been able to discover about a dozen black holes within the Milky Way. Without indulging in calculations, we note that there are about 100–400 billion stars in our galaxy, and approximately every thousandth star has enough mass to form a black hole. It is likely that millions of black holes could have formed during the existence of the Milky Way. Since it is easier to detect black holes of enormous size, it is logical to assume that most likely the majority of black holes in our galaxy are not supermassive. It is noteworthy that NASA research in 2005 suggests the presence of a whole swarm of black holes (10-20 thousand) revolving around the center of the galaxy. In addition, in 2016, Japanese astrophysicists discovered a massive satellite near the object Sagittarius A* - a black hole, the core of the Milky Way. Due to the small radius (0.15 light years) of this body, as well as its enormous mass (100,000 solar masses), scientists assume that this object is also a supermassive black hole.

The core of our galaxy, the black hole of the Milky Way (Sagittarius A*, Sgr A* or Sagittarius A*) is supermassive and has a mass of 4.31 106 solar masses, and a radius of 0.00071 light years (6.25 sv.h. or 6.75 billion km). The temperature of Sagittarius A*, together with the cluster around it, is about 1·107 K.

The largest black hole

Quasar S5_0014+81 is 12 billion light years away from the Solar System.

The largest black hole in the Universe that scientists have discovered is a supermassive black hole, FSRQ blazar, in the center of the galaxy S5 0014+81, at a distance of 1.2 1010 light years from Earth. According to preliminary observation results using the Swift space observatory, the mass of the black hole was 40 billion (40·109) solar masses, and the Schwarzschild radius of such a hole was 118.35 billion kilometers (0.013 light years). In addition, according to calculations, it arose 12.1 billion years ago (1.6 billion years after the Big Bang). If this giant black hole does not absorb the matter surrounding it, it will live to the era of black holes - one of the eras of the development of the Universe, during which black holes will dominate in it. If the core of the galaxy S5 0014+81 continues to grow, it will become one of the last black holes that will exist in the Universe.

First recorded gravitational wave signal GW150914

The other two known black holes, although they do not have their own names, are of greatest importance for the study of black holes, since they confirmed their existence experimentally, and also provided important results for the study of gravity. We are talking about the event GW150914, which is the collision of two black holes into one. This event made it possible to register gravitational waves.

A

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Detection of black holes

Before considering methods for detecting black holes, we should answer the question - why is a black hole black? – the answer to this does not require deep knowledge of astrophysics and cosmology. The fact is that a black hole absorbs all the radiation incident on it and does not emit at all, if you do not take into account the hypothetical Hawking radiation. If we consider this phenomenon in more detail, we can assume that processes leading to the release of energy in the form of electromagnetic radiation do not occur inside black holes. Then, if a black hole emits, it does so in the Hawking spectrum (which coincides with the spectrum of a heated, absolutely black body). However, as mentioned earlier, this radiation was not detected, which suggests that the temperature of black holes is completely low.

Bending of light near a black hole

Another generally accepted theory says that electromagnetic radiation is not at all capable of leaving the event horizon. It is most likely that photons (particles of light) are not attracted by massive objects, since, according to the theory, they themselves have no mass. However, the black hole still “attracts” photons of light through the distortion of space-time. If we imagine a black hole in space as a kind of depression on the smooth surface of space-time, then there is a certain distance from the center of the black hole, approaching which light will no longer be able to move away from it. That is, roughly speaking, the light begins to “fall” into a “hole” that does not even have a “bottom”.

In addition, if we take into account the effect of gravitational redshift, it is possible that light in a black hole loses its frequency, shifting along the spectrum into the region of low-frequency long-wave radiation until it loses energy altogether.

So, a black hole is black in color and therefore difficult to detect in space.

What can deviations in respiratory rate indicate?

Breathing is controlled by the brain, which sends appropriate signals to the respiratory muscles. Inhalations and exhalations occur automatically, that is, a person does not mentally track these processes.

Sometimes the body needs to adjust the frequency of breathing movements. Receptors in the brain detect a lack of oxygen or an excess of carbon dioxide, and then send information to the periphery about how to change the breathing pattern.

Stress can cause rapid breathing

Abnormalities in respiratory rate can indicate a number of different problems. A high or low breathing rate can be a consequence of physical activity. In such cases, an increase in the frequency of inhalations and exhalations does not indicate physiological disorders.

However, sometimes various diseases, injuries or certain chemical compounds lead to adjustments in breathing. If your doctor notices abnormalities in your breathing rate that are not related to physical activity, he or she will try to identify medical problems.

In 2021, Japanese scientists conducted a study that examined information about 15 thousand patients who visited emergency medical centers. It was found that a high respiratory rate was a predictor of worsening medical problems after discharge.

People with higher respiratory rates returned to hospital more often compared to those patients who did not have abnormalities.

Respiratory rate can be affected by many factors, such as injury, physical activity, emotions, mood, and a number of medical conditions.

Detection methods

Let's look at the methods that astronomers use to detect a black hole:

A black hole can be detected when it attracts the matter surrounding it, be it the stellar matter of a neighboring star or a gas cloud through which a black hole is moving. Computer simulations show a star falling into a black hole. In this case, visible matter will begin to be drawn towards the massive object, forming an accretion disk around it. That is, a disk of rapidly rotating heated matter. In some cases, matter rotating around a black hole can tightly block the black hole, thereby visually forming a huge luminous sphere.
Animation of stars rotating around the supermassive black hole Sagittarius A
The gravitational perturbation method makes it possible to determine the presence of a black hole by its gravitational influence on surrounding bodies. For example, if the trajectory of a planet around a certain star does not agree with theoretical calculations of the orbit of this planet, but has some distortion, we can assume the presence of a massive object near the planet that affects its trajectory. This special case is simplified, since such situations make it possible to detect less massive objects, such as other planets. Black holes can distort the trajectory of huge clouds of gas.
Returning to the change in the trajectory of electromagnetic radiation near a black hole, we should note one of the phenomena that also makes it possible to detect a black hole - gravitational lensing. Light passing near the boundaries of a black hole slightly changes its trajectory, thus creating a blurred or distorted picture, and sometimes even a duplicated image of cosmic bodies. Thus, a black hole located against the background of a cluster, such as a galaxy or nebula, gives an anomalous image of this cluster, which attracts astronomers and gives rise to a reason to start searching for black holes in this region of the sky.

In addition to the methods mentioned above, scientists often associate objects such as black holes and quasars. Quasars are certain clusters of cosmic bodies and gas, which are among the brightest astronomical objects in the Universe. Since they have a high luminescence intensity at relatively small sizes, there is reason to assume that the center of these objects is a supermassive black hole, attracting surrounding matter. Due to such a powerful gravitational attraction, the attracted matter is so heated that it radiates intensely. The discovery of such objects is usually compared with the discovery of a black hole. Sometimes quasars can emit jets of heated plasma in two directions - relativistic jets. The reasons for the appearance of such jets are not entirely clear, but they are probably caused by the interaction of the magnetic fields of the black hole and the accretion disk, and are not emitted by the direct black hole.

Jet in the M87 galaxy shooting from the center of the black hole

To summarize the above, you can imagine what a black hole looks like in space up close: it is a spherical black object around which highly heated matter rotates, forming a glowing accretion disk.

Steps

Ask for consent from the person whose breathing rate you want to determine.

There is a theory that it is best to check the breathing rate without warning, in order to exclude the influence of external factors and the nervous system. However, this is not a good idea from an ethical point of view.

Choose a place with good lighting and find a clock with a second hand (or stopwatch).

Ask the person to sit up straight and straighten their back.

Make sure he is not nervous. The breathing rate should be checked in a calm, relaxed environment.

It is important to rule out breathing problems. Their main signs are: cold, damp skin, blueness of the lips, tongue, nail plates or mucous membrane of the cheek, raising the shoulder girdle when breathing, intermittent speech. Place your palm on the person's upper chest, just below the collarbone.

Place your palm on the person's upper chest, just below the collarbone.

Wait until the second hand of the watch is at 12 or 6.

This will make it easier to start counting.

Count the number of breaths you take using your chest movements. One breathing movement includes 1 inhalation and 1 exhalation

Pay attention to your breaths - this will make counting easier

Stop counting after 1 minute.

The normal respiratory rate is 12 - 18. Consult a doctor if the readings are below 12 or above 25 - this indicates breathing problems.

The following reasons may explain slow or fast breathing:

Children breathe faster than adults. Rapid breathing can be caused by nervousness, exercise, loud or fast music, or high altitude. Breathing problems can also be caused by medical reasons such as anemia, fever, brain disease, cardiovascular disease, pneumonia, asthma or other respiratory diseases.
Elderly people breathe slower. Breathing also slows down during sleep or a relaxed state. Medical reasons can be: taking narcotic drugs (in particular morphine), lung diseases, cerebral edema, diseases in the last stages.

Check for the following symptoms that may indicate breathing problems:

Uneven breathing. Does a person inhale and exhale at the same rate? Irregular breathing movements may indicate breathing problems.
Depth of breathing. Is breathing deep (the chest expands slightly) or shallow? Older people tend to breathe shallowly.
Do the right and left sides of the chest expand equally during inhalation?
Sound while breathing. Are there any sounds during breathing, such as wheezing, gurgling, rumbling, do they occur during inhalation or exhalation? To differentiate them, use a phonendoscope or stethoscope.

When listening to sounds while breathing, use a stethoscope, resting it on your naked body.
The first few times, you can check the breathing rate and listen for lung sounds separately. When you gain more experience, you can do both at the same time.
You can determine your breathing rate using chest excursion; placing your hand on your chest will also help. If a person wears loose clothing, chest excursion will be more difficult to determine.
Pregnant women and obese people breathe at an irregular rate.
Once you have gained experience in determining your breathing rate, you can determine the number of breaths in 30 seconds and multiply this value by two. This can be done if the person breathes regularly

Related materials

One of the most interesting phenomena in astrophysics is the collision of black holes, which also makes it possible to detect such massive astronomical bodies. Such processes are of interest not only to astrophysicists, since they result in phenomena poorly studied by physicists. The most striking example is the previously mentioned event called GW150914, when two black holes came so close that, as a result of their mutual gravitational attraction, they merged into one. An important consequence of this collision was the emergence of gravitational waves.

According to the definition, gravitational waves are changes in the gravitational field that propagate in a wave-like manner from massive moving objects. When two such objects come closer, they begin to rotate around a common center of gravity. As they get closer, their rotation around their own axis increases. Such alternating oscillations of the gravitational field at some moment can form one powerful gravitational wave, which can spread through space for millions of light years. Thus, at a distance of 1.3 billion light years, two black holes collided, generating a powerful gravitational wave that reached the Earth on September 14, 2015 and was recorded by the LIGO and VIRGO detectors.

How do black holes die?

Obviously, for a black hole to cease to exist, it would need to lose all of its mass. However, according to its definition, nothing can leave the black hole if it has crossed its event horizon. It is known that the possibility of emission of particles from a black hole was first mentioned by the Soviet theoretical physicist Vladimir Gribov, in his discussion with another Soviet scientist Yakov Zeldovich. He argued that from the point of view of quantum mechanics, a black hole is capable of emitting particles through the tunneling effect. Later, using quantum mechanics, the English theoretical physicist Stephen Hawking built his own, slightly different theory. You can read more about this phenomenon here. Briefly speaking, in a vacuum there are so-called virtual particles, which are constantly born in pairs and annihilate each other, without interacting with the outside world. But if such pairs appear on the event horizon of a black hole, then strong gravity is hypothetically capable of separating them, with one particle falling into the black hole and the other moving away from the black hole. And since a particle flying away from a hole can be observed, and therefore has positive energy, then a particle falling into a hole must have negative energy. Thus, the black hole will lose its energy and an effect will occur, which is called black hole evaporation.

According to existing models of a black hole, as mentioned earlier, as its mass decreases, its radiation becomes more intense. Then, at the final stage of the black hole's existence, when it may shrink to the size of a quantum black hole, it will release a huge amount of energy in the form of radiation, which could be equivalent to thousands or even millions of atomic bombs. This event is somewhat reminiscent of the explosion of a black hole, like the same bomb. According to calculations, primordial black holes could have been born as a result of the Big Bang, and those of them with a mass of about 1012 kg would have evaporated and exploded around our time. Be that as it may, such explosions have never been noticed by astronomers.

Despite Hawking's proposed mechanism for destroying black holes, the properties of Hawking's radiation cause a paradox within the framework of quantum mechanics. If a black hole absorbs a certain body, and then loses the mass resulting from the absorption of this body, then regardless of the nature of the body, the black hole will not differ from what it was before absorbing the body. In this case, information about the body is forever lost. From the point of view of theoretical calculations, the transformation of the initial pure state into the resulting mixed (“thermal”) state does not correspond to the current theory of quantum mechanics. This paradox is sometimes called the disappearance of information in a black hole. A definitive solution to this paradox has never been found. Known solutions to the paradox:

The invalidity of Hawking's theory. This entails the impossibility of destroying a black hole and its constant growth.
Presence of white holes. In this case, the absorbed information does not disappear, but is simply thrown out into another Universe.
The inconsistency of the generally accepted theory of quantum mechanics.

Advantages and disadvantages

The positive qualities of net present value include:

designation of clear criteria that guide the final decision;
the cost of cash investments is taken into account in real time (using special formulas);
The NPV shows the risk of the project.

Negative qualities include:

there is no guarantee of a certain outcome of events. In other words, the indicator does not take into account risks. But this is not such a big drawback, because it is the NPV that is used to identify possible risks associated with investing. The higher the discount rate, the greater the risk the investor expects, and vice versa;
does not take into account the intangible assets and property of the organization;
The discount rate is quite difficult to calculate. This may affect the final value of discounted income and distort its results. Such situations arise especially often when implementing complex projects associated with a large number of risks.

Unsolved problem of black hole physics

Judging by everything that was described earlier, black holes, although they have been studied for a relatively long time, still have many features, the mechanisms of which are still unknown to scientists.

In 1970, an English scientist formulated the so-called. “the principle of cosmic censorship” - “Nature abhors naked singularity.” This means that singularities form only in hidden places, like the center of a black hole. However, this principle has not yet been proven. There are also theoretical calculations according to which a “naked” singularity can arise.
The “no hair theorem”, according to which black holes have only three parameters, has not been proven either.
A complete theory of the black hole magnetosphere has not been developed.
The nature and physics of the gravitational singularity have not been studied.
It is not known for certain what happens at the final stage of the existence of a black hole, and what remains after its quantum decay.

ChSV, which means danger in youth slang

In addition, communication with parents becomes more difficult, since they are not an authority for the teenager. The only correct option, choice and opinion is his personal one.

ChSV, which means danger in youth slang:

The term was first used by Carlos Castaneda in his works. He is a philosopher, thinker, esotericist, and also an anthropologist, whose works were received ambiguously. It was he who came up with this abbreviation and first began to use it in the work about Don Juan.
In this case, we were talking about a magician who often participated in various rituals. In his opinion, in order to connect with spirits, with nature, it is necessary to completely abandon the sense of self-importance and dignity, as if to devalue oneself.
Now, mainly in social networks, VKontakte, the abbreviation is used with some negative meaning, and means that a person is arrogant, selfish, self-centered and arrogant.

In harmony with the world
Experts believe that people with high heart rate can be patients of psychologists, because arrogance often turns into delusions of grandeur. This is a psychological problem that can become a real obstacle to a successful life.

Interesting facts about black holes

Summarizing the above, we can highlight several interesting and unusual features of the nature of black holes:

BHs have only three parameters: mass, electric charge and angular momentum. As a result of such a small number of characteristics of this body, the theorem stating this is called the “no-hair theorem”. This is also where the phrase “a black hole has no hair” came from, which means that two black holes are absolutely identical, their three parameters mentioned are the same.
The density of the black hole can be less than the density of air, and the temperature is close to absolute zero. From this we can assume that the formation of a black hole does not occur due to compression of matter, but as a result of the accumulation of a large amount of matter in a certain volume.
Time passes much slower for bodies absorbed by a black hole than for an external observer. In addition, the absorbed bodies stretch significantly inside the black hole, which scientists call spaghettification.
There may be about a million black holes in our galaxy.
There is probably a supermassive black hole at the center of every galaxy.
In the future, according to the theoretical model, the Universe will reach the so-called era of black holes, when black holes will become the dominant bodies in the Universe.