The meaning of the word gravity. Gravity is not at all “The Law of Universal Gravitation” Gravity as the most important factor in the structure of the Universe

I decided, to the best of my ability, to dwell on lighting in more detail. scientific heritage Academician Nikolai Viktorovich Levashov, because I see that his works today are not yet in demand as they should be in a society of truly free and reasonable people. People are still do not understand the value and importance of his books and articles, because they do not realize the degree of deception in which we have been living for the last couple of centuries; do not understand that information about nature, which we consider familiar and therefore true, is 100% false; and they were deliberately imposed on us in order to hide the truth and prevent us from developing in the right direction...

Law of Gravity

Why do we need to deal with this gravity? Isn't there something else we know about her? Come on! We already know a lot about gravity! For example, Wikipedia kindly tells us that « Gravity (attraction, worldwide, gravity) (from Latin gravitas - “gravity”) - the universal fundamental interaction between all material bodies. In the approximation of low speeds and weak gravitational interaction, it is described by Newton’s theory of gravity, in the general case it is described by Einstein’s general theory of relativity...” Those. Simply put, this Internet chatter says that gravity is the interaction between all material bodies, and even more simply put - mutual attraction material bodies to each other.

We owe the appearance of such an opinion to Comrade. Isaac Newton, who is credited with the discovery in 1687 "The Law of Universal Gravitation", according to which all bodies are supposedly attracted to each other in proportion to their masses and inversely proportional to the square of the distance between them. The good news is that Comrade. Isaac Newton is described in Pedia as a highly educated scientist, unlike Comrade. , who is credited with the discovery electricity…

It is interesting to look at the dimension of the “Force of Attraction” or “Force of Gravity”, which follows from Comrade. Isaac Newton, having the following form: F=m 1 *m 2 /r 2

The numerator is the product of the masses of two bodies. This gives the dimension “kilograms squared” - kg 2. The denominator is “distance” squared, i.e. meters squared - m 2. But strength is not measured in strange kg 2 /m 2, and in no less strange kg*m/s 2! It turns out to be an inconsistency. To remove it, “scientists” came up with a coefficient, the so-called. "gravitational constant" G , equal to approximately 6.67545×10 −11 m³/(kg s²). If we now multiply everything, we get the correct dimension of “Gravity” in kg*m/s 2, and this abracadabra is called in physics "newton", i.e. force in today's physics is measured in "".

I wonder what physical meaning has a coefficient G , for something reducing the result in 600 billions of times? None! “Scientists” called it the “coefficient of proportionality.” And they introduced it for adjustment dimensions and results to suit the most desirable! This is the kind of science we have today... It should be noted that, in order to confuse scientists and hide contradictions, measurement systems in physics were changed several times - the so-called. "systems of units". Here are the names of some of them, which replaced each other as the need arose to create new camouflages: MTS, MKGSS, SGS, SI...

It would be interesting to ask comrade. Isaac: a how did he guess that there is a natural process of attracting bodies to each other? How did he guess, that the “Force of attraction” is proportional precisely to the product of the masses of two bodies, and not to their sum or difference? How did he so successfully comprehend that this Force is inversely proportional to the square of the distance between bodies, and not to the cube, doubling or fractional power? Where at comrade such inexplicable guesses appeared 350 years ago? After all, he did not conduct any experiments in this area! And, if you believe the traditional version of history, in those days even the rulers were not yet completely straight, but here is such an inexplicable, simply fantastic insight! Where?

Yes out of nowhere! Comrade Isaac had no idea about anything like that and didn’t investigate anything like that and didn't open. Why? Because in reality the physical process " attraction tel" to each other does not exist, and, accordingly, there is no Law that would describe this process (this will be convincingly proven below)! In reality, Comrade Newton in our inarticulate, simply attributed the discovery of the law of “Universal Gravity”, simultaneously awarding him the title of “one of the creators of classical physics”; in the same way as at one time they attributed to comrade. Bene Franklin, which had 2 classes education. In “Medieval Europe” this was not the case: there was great tension not only with the sciences, but simply with life...

But, fortunately for us, at the end of the last century, the Russian scientist Nikolai Levashov wrote several books in which he gave the “alphabet and grammar” undistorted knowledge; returned to earthlings the previously destroyed scientific paradigm, with the help of which easily explained almost all “unsolvable” mysteries of earthly nature; explained the basics of the structure of the Universe; showed under what conditions on all planets on which necessary and sufficient conditions appear, Life- living matter. Explained what kind of matter can be considered living, and what physical meaning natural process called life" He further explained when and under what conditions “living matter” acquires Intelligence, i.e. realizes its existence - becomes intelligent. Nikolay Viktorovich Levashov conveyed a lot to people in his books and films undistorted knowledge. Among other things, he explained what "gravity", where it comes from, how it works, what its actual physical meaning is. Most of all this is written in books and. Now let’s look at the “Law of Universal Gravitation”...

The “law of universal gravitation” is a fiction!

Why do I so boldly and confidently criticize physics, the “discovery” of Comrade. Isaac Newton and the “great” “Law of Universal Gravitation” itself? Yes, because this “Law” is a fiction! Deception! Fiction! A scam on a global scale to take earthly science to a dead end! The same scam with the same goals as the notorious “Theory of Relativity” by Comrade. Einstein.

Proof? If you please, here they are: very precise, strict and convincing. They were superbly described by the author O.Kh. Derevensky in his wonderful article. Due to the fact that the article is quite lengthy, I will give here a very brief version of some evidence of the falsity of the “Law of Universal Gravitation”, and citizens interested in the details will read the rest themselves.

1. In our Solar system Only planets and the Moon, a satellite of the Earth, have gravity. The satellites of the other planets, and there are more than six dozen of them, do not have gravity! This information is completely open, but not advertised by the “scientific” people, because it is inexplicable from the point of view of their “science”. Those. b O Most of the objects in our solar system do not have gravity - they do not attract each other! And this completely refutes the “Law of Universal Gravitation”.

2. Henry Cavendish's experience the attraction of massive ingots to each other is considered irrefutable evidence of the presence of attraction between bodies. However, despite its simplicity, this experience has not been openly reproduced anywhere. Apparently, because it does not give the effect that some people once announced. Those. Today, with the possibility of strict verification, experience does not show any attraction between bodies!

3. Launch of an artificial satellite into orbit around an asteroid. Mid February 2000 Americans sent a space probe NEAR close enough to the asteroid Eros, leveled the speed and began to wait for the probe to be captured by the gravity of Eros, i.e. when the satellite is gently attracted by the asteroid's gravity.

But for some reason the first date didn’t go well. The second and subsequent attempts to surrender to Eros had exactly the same effect: Eros did not want to attract the American probe NEAR, and without additional engine support, the probe did not stay near Eros . This cosmic date ended in nothing. Those. no attraction between probe and ground 805 kg and an asteroid weighing more than 6 trillion tons could not be found.

Here we cannot fail to note the inexplicable tenacity of the Americans from NASA, because the Russian scientist Nikolay Levashov, living at that time in the USA, which he then considered a completely normal country, wrote, translated into English and published in 1994 year, his famous book, in which he explained “on the fingers” everything that specialists from NASA needed to know in order for their probe NEAR did not hang around as a useless piece of iron in space, but brought at least some benefit to society. But, apparently, exorbitant conceit played its trick on the “scientists” there.

4. Next try decided to repeat the erotic experiment with an asteroid Japanese. They chose an asteroid called Itokawa, and sent it on May 9 2003 year, a probe called (“Falcon”) was added to it. In September 2005 year, the probe approached the asteroid at a distance of 20 km.

Taking into account the experience of the “dumb Americans,” the smart Japanese equipped their probe with several engines and an autonomous short-range navigation system with laser rangefinders, so that it could approach the asteroid and move around it automatically, without the participation of ground operators. “The first number of this program turned out to be a comedy stunt with the landing of a small research robot on the surface of an asteroid. The probe descended to the calculated height and carefully dropped the robot, which was supposed to slowly and smoothly fall to the surface. But... he didn’t fall. Slow and smooth he was carried away somewhere far from the asteroid. There he disappeared without a trace... The next number of the program turned out to be, again, a comedy trick with a short-term landing of a probe on the surface “to take a soil sample.” It became comedic because, to ensure the best performance of laser rangefinders, a reflective marker ball was dropped onto the surface of the asteroid. There were no engines on this ball either and... in short, the ball was not in the right place... So whether the Japanese "Falcon" landed on Itokawa, and what he did on it if he sat down, is unknown to science..." Conclusion: the Japanese miracle Hayabusa did not was able to discover no attraction between probe ground 510 kg and an asteroid mass 35 000 tons

Separately, I would like to note that a comprehensive explanation of the nature of gravity by the Russian scientist Nikolay Levashov gave in his book, which he first published in 2002 year - almost a year and a half before the launch of the Japanese Falcon. And, despite this, the Japanese “scientists” followed exactly in the footsteps of their American colleagues and carefully repeated all their mistakes, including landing. This is such an interesting continuity of “scientific thinking”...

5. Where do tides come from? A very interesting phenomenon described in the literature, to put it mildly, is not entirely correct. “...There are textbooks on physics, where it is written what they should be - in accordance with the “law of universal gravitation”. There are also tutorials on oceanography, where it is written what they are, the tides, In fact.

If the law of universal gravitation operates here, and ocean water is attracted, among other things, to the Sun and the Moon, then the “physical” and “oceanographic” patterns of tides should coincide. So do they match or not? It turns out that to say that they do not coincide is to say nothing. Because the “physical” and “oceanographic” pictures have no relation to each other at all nothing in common... The actual picture of tidal phenomena differs so greatly from the theoretical one - both qualitatively and quantitatively - that on the basis of such a theory it is impossible to pre-calculate tides impossible. Yes, no one is trying to do this. Not crazy after all. This is how they do it: for each port or other point that is of interest, the dynamics of the ocean level are modeled by the sum of oscillations with amplitudes and phases that are found purely empirically. And then they extrapolate this amount of fluctuations forward - and you get pre-calculations. The captains of the ships are happy - well, okay!..” This all means that our earthly tides are too don't obey"The law of universal gravitation."

What is gravity really?

The real nature of gravity was clearly described for the first time in modern history by academician Nikolai Levashov in a fundamental scientific work. So that the reader can better understand what is written regarding gravity, I will give a small preliminary explanation.

The space around us is not empty. It is completely filled with many different matters, which Academician N.V. Levashov named "prime matters". Previously, scientists called all this riot of matter "ether" and even received convincing evidence of its existence (the famous experiments of Dayton Miller, described in the article by Nikolai Levashov “The Theory of the Universe and Objective Reality”). Modern “scientists” have gone much further and now they "ether" called "dark matter". Colossal progress! Some matters in the “ether” interact with each other to one degree or another, some do not. And some primary matter begins to interact with each other, falling into changed external conditions in certain space curvatures (inhomogeneities).

Space curvatures appear as a result of various explosions, including “supernova explosions.” « When a supernova explodes, fluctuations in the dimensionality of space arise, similar to the waves that appear on the surface of water after throwing a stone. The masses of matter ejected during the explosion fill these inhomogeneities in the dimension of space around the star. From these masses of matter, planets (and) begin to form..."

Those. planets are not formed from space debris, as modern “scientists” for some reason claim, but are synthesized from the matter of stars and other primary matters, which begin to interact with each other in suitable inhomogeneities of space and form the so-called. "hybrid matter". It is from these “hybrid matters” that planets and everything else in our space are formed. our planet, just like the other planets, is not just a “piece of stone”, but a very complex system consisting of several spheres nested one inside the other (see). The densest sphere is called the “physically dense level” - this is what we see, the so-called. physical world. Second in terms of density, a slightly larger sphere is the so-called “ethereal material level” of the planet. Third sphere – “astral material level”. Fourth sphere is the “first mental level” of the planet. Fifth sphere is the “second mental level” of the planet. AND sixth sphere is the “third mental level” of the planet.

Our planet should be considered only as the totality of these six spheres– six material levels of the planet, nested one within the other. Only in this case can you get a complete understanding of the structure and properties of the planet and the processes occurring in nature. The fact that we are not yet able to observe the processes occurring outside the physically dense sphere of our planet does not indicate that “there is nothing there,” but only that at present our senses are not adapted by nature for these purposes. And one more thing: our Universe, our planet Earth and everything else in our Universe is formed from seven various types of primordial matter merged into six hybrid matters. And this is neither a divine nor a unique phenomenon. This is simply the qualitative structure of our Universe, determined by the properties of the heterogeneity in which it was formed.

Let's continue: planets are formed by the merging of the corresponding primary matter in areas of inhomogeneity in space that have properties and qualities suitable for this. But these, as well as all other areas of space, contain a huge number of primordial matters(free forms of matter) of various types that do not interact or interact very weakly with hybrid matter. Finding themselves in an area of heterogeneity, many of these primary matters are affected by this heterogeneity and rush to its center, in accordance with the gradient (difference) of space. And, if a planet has already formed in the center of this heterogeneity, then the primary matter, moving towards the center of the heterogeneity (and the center of the planet), creates directional flow, which creates the so-called. gravitational field. And, accordingly, under gravity You and I need to understand the impact of the directed flow of primary matter on everything in its path. That is, simply put, gravity is pressing material objects to the surface of the planet by the flow of primary matter.

Is not it, reality very different from the fictitious law of “mutual attraction”, which supposedly exists everywhere for a reason that no one understands. Reality is much more interesting, much more complex and much simpler, at the same time. Therefore, the physics of real natural processes is much easier to understand than fictitious ones. And the use of real knowledge leads to real discoveries and the effective use of these discoveries, and not to concocted ones.

Antigravity

As an example of today's scientific profanation we can briefly analyze the explanation by “scientists” of the fact that “rays of light are bent near large masses,” and therefore we can see what is hidden from us by stars and planets.

Indeed, we can observe objects in Space that are hidden from us by other objects, but this phenomenon has nothing to do with the masses of objects, because the “universal” phenomenon does not exist, i.e. no stars, no planets NOT attract no rays to themselves and do not bend their trajectory! Why then do they “bend”? There is a very simple and convincing answer to this question: rays are not bent! They're just do not spread in a straight line, as we are accustomed to understand, but in accordance with shape of space. If we consider a ray passing near a large cosmic body, then we must keep in mind that the ray bends around this body because it is forced to follow the curvature of space, like a road of the appropriate shape. And there is simply no other way for the beam. The beam cannot help but bend around this body, because the space in this area has such a curved shape... A small addition to what has been said.

Now, returning to antigravity, it becomes clear why Humanity is unable to catch this nasty “anti-gravity” or achieve at least anything of what the clever functionaries of the dream factory show us on TV. We are deliberately forced For more than a hundred years, internal combustion engines or jet engines have been used almost everywhere, although they are very far from perfect in terms of operating principle, design, and efficiency. We are deliberately forced extract using various generators of cyclopean sizes, and then transmit this energy through wires, where b O most of it dissipates in space! We are deliberately forced to live the life of irrational beings, therefore we have no reason to be surprised that we are not succeeding in anything meaningful either in science, or in technology, or in economics, or in medicine, or in organizing a decent life in society.

I will now give you several examples of the creation and use of antigravity (aka levitation) in our lives. But these methods of achieving antigravity were most likely discovered by chance. And in order to consciously create a truly useful device that implements antigravity, you need to know the real nature of the phenomenon of gravity, study it, analyze and understand its whole essence! Only then can we create something sensible, effective and truly useful to society.

The most common device in our country that uses antigravity is balloon and its many variations. If it is filled with warm air or gas that is lighter than the atmospheric gas mixture, the ball will tend to fly up rather than down. This effect has been known to people for a very long time, but still does not have a comprehensive explanation– one that would no longer raise new questions.

A short search on YouTube led to the discovery of a large number of videos showing very real examples of antigravity. I will list some of them here so that you can see that antigravity ( levitation) really exists, but... has not yet been explained by any of the “scientists”, apparently pride does not allow...

The content of the article

GRAVITY (GRAVITY), the property of matter that states that attractive forces exist between any two particles. Gravity is a universal interaction that covers the entire observable Universe and is therefore called universal. As we will see later, gravity plays a primary role in determining the structure of all astronomical bodies in the Universe, except the smallest. It organizes astronomical bodies into systems like our Solar System or the Milky Way, and underlies the structure of the Universe itself.

“Gravity” is usually understood as the force created by the gravity of a massive body, and “gravity acceleration” is the acceleration created by this force. (The word “massive” is used here in the sense of “having mass,” but the body in question does not necessarily have to have a very large mass.) In an even narrower sense, the acceleration of gravity refers to the acceleration of a body freely falling (ignoring air resistance) on the surface of the Earth . In this case, since the entire “Earth plus falling body” system rotates, inertial forces come into play. Centrifugal force counteracts the gravitational force and reduces the effective weight of the body by a small but measurable amount. This effect drops to zero at the poles, through which the Earth's axis of rotation passes, and reaches a maximum at the equator, where the Earth's surface is the greatest distance from the axis of rotation. In any locally conducted experiment, the effect of this force is indistinguishable from the true force of gravity. Therefore, the expression “gravity on the surface of the Earth” usually means the combined action of true gravity and centrifugal reaction. It is convenient to extend the term “gravity” to other celestial bodies, saying, for example, “gravity on the surface of the planet Mars.”

The acceleration of gravity on the Earth's surface is 9.81 m/s 2 . This means that any body freely falling near the surface of the Earth increases its speed (accelerates) by 9.81 m/s for each second of fall. If the body began free fall from a state of rest, then by the end of the first second it will have a speed of 9.81 m/s, by the end of the second - 18.62 m/s, etc.

Gravity as the most important factor in the structure of the Universe.

In the structure of the world around us, gravity plays an extremely important, fundamental role. Compared to the electrical forces of attraction and repulsion between two charged elementary particles, gravity is very weak. The ratio of the electrostatic force to the gravitational force acting between two electrons is about 4H 10 46, i.e. 4 followed by 46 zeros. The reason why such a large gap in magnitude is not found at every step in everyday life is that the predominant part of matter in its ordinary form is electrically almost neutral, since the number of positive and negative charges in its volume is the same. Therefore, the enormous electrical forces of volume simply do not have the opportunity to fully develop. Even in such “tricks” as sticking a frayed balloon to the ceiling and raising hair when combing it on a dry day, the electrical charges are separated only slightly, but this is already enough to overcome the forces of gravity. The force of gravitational attraction is so weak that it is possible to measure its effect between bodies of ordinary sizes in laboratory conditions only if special precautions are taken. For example, the force of gravitational attraction between two people weighing 80 kg, standing closely with their backs to each other, is several tenths of a dyne (less than 10 -5 N). Measurements of such weak forces are complicated by the need to isolate them from the background of various kinds of extraneous forces that may exceed the one being measured.

As mass increases, gravitational effects become more noticeable and eventually begin to dominate all others. Let's imagine the conditions prevailing on one of the small asteroids of the Solar System - on a spherical rock block with a radius of 1 km. The force of gravity on the surface of such an asteroid is 1/15,000 of the force of gravity on the surface of the Earth, where the acceleration due to gravity is 9.81 m/s 2 . A mass weighing one ton on the surface of the Earth would weigh about 50 g on the surface of such an asteroid. The lift-off speed (at which the body, moving radially from the center of the asteroid, overcomes the gravitational field created by the latter) would be only 1.2 m/s, or 4 km/h (the speed of a not very fast walking pedestrian), so when walking on the surface of an asteroid, one would have to avoid sudden movements and not exceed the specified speed, so as not to fly away forever into outer space. The role of self-gravity grows as we move to increasingly larger bodies - the Earth, large planets like Jupiter, and, finally, to stars such as the Sun. Thus, self-gravity maintains the spherical shape of the liquid core of the Earth and its solid mantle surrounding this core, as well as the earth’s atmosphere. Intermolecular cohesive forces that hold particles of solids and liquids together are no longer effective on a cosmic scale, and only self-gravity allows such giant gas balls as stars to exist as a whole. Without gravity, these bodies simply would not exist, just as there would be no worlds suitable for life.

When moving to even larger scales, gravity organizes individual celestial bodies into systems. The sizes of such systems vary - from relatively small (from an astronomical point of view) and simple systems, such as the Earth-Moon system, the Solar system and double or multiple stars, to large star clusters numbering hundreds of thousands of stars. The “life,” or evolution, of an individual star cluster can be viewed as a balancing act between the mutual divergence of stars and gravity, which tends to hold the cluster together as a whole. From time to time, a star, moving in the direction of other stars, acquires momentum and speed from them, allowing it to fly out of the cluster and leave it forever. The remaining stars form an even tighter cluster, and gravity binds them together even more tightly than before. Gravity also helps keep gas and dust clouds together in outer space, and sometimes even compresses them into compact and more or less spherical clumps of matter. The dark silhouettes of many of these objects can be seen against the brighter background of the Milky Way. According to the theory of star formation accepted today, if the mass of such an object is large enough, then the pressure in its depths reaches a level at which nuclear reactions become possible, and a dense clump of matter turns into a star. Astronomers were able to obtain images confirming the formation of stars in those places in outer space where previously only clouds of matter were observed, which testifies in favor of the existing theory.

Gravity plays a vital role in all theories of the origin, development and structure of the Universe as a whole. Almost all of them are based on the general theory of relativity. In this theory, created by Einstein at the beginning of the 20th century, gravity is considered as a property of the four-dimensional geometry of space-time, as something similar to the curvature of a spherical surface, generalized to a larger number of dimensions. The “curvature” of space-time is closely related to the distribution of matter in it.

All cosmological theories accept that gravity is a property of any type of matter, manifesting itself everywhere in the Universe, although it is by no means assumed that the effects created by gravity are the same everywhere. For example, the gravitational constant G(which we will discuss further) may vary depending on place and time, although there is no direct observational data to confirm this yet. Gravitational constant G- one of the physical constants of our world, just like the speed of light or the electric charge of an electron or proton. With the accuracy with which modern experimental methods make it possible to measure this constant, its value does not depend on what type of matter creates gravity. Only mass matters. Mass can be understood in two ways: as a measure of the ability to attract other bodies - this property is meant when they talk about heavy (gravitational) mass - or as a measure of a body’s resistance to attempts to accelerate it (to set it in motion if the body is at rest, to stop if the body moves, or change its trajectory), - this property of mass is meant when they talk about inertial mass. Intuitively, these two types of mass do not seem to be the same property of matter, but the general theory of relativity postulates their identity and builds a picture of the world based on this postulate.

Gravity has another feature; there appears to be no conceivable way of getting rid of the effects of gravity except by moving an infinite distance away from all matter. No known substance has a negative mass, i.e. property of being repelled by a gravitational field. Even antimatter (positrons, antiprotons, etc.) has positive mass. It is impossible to get rid of gravity with the help of some kind of screen, like with an electric field. During lunar eclipses, the Moon is “shielded” by the Earth from the attraction of the Sun, and the effect of such shielding would accumulate from one eclipse to another, but this is not the case.

History of ideas about gravity.

As shown above, gravity is one of the most common interactions of matter with matter and at the same time one of the most mysterious and enigmatic. Modern theories have not come any significantly closer to explaining the phenomenon of gravity.

Nevertheless, gravity has always been explicitly or implicitly intertwined with cosmology, so that the two are inseparable. The first cosmologies, such as those of Aristotle and Ptolemy, lasted until the 18th century. largely due to the authority of these thinkers, they were hardly anything more than a systematization of the naive views of the ancients. In these cosmologies, matter was divided into four classes, or "elements": earth, water, air, and fire (in order from heaviest to lightest). The words "gravity" originally meant simply "heaviness"; objects consisting of the element “earth” had the property of “heaviness” to a greater extent than objects consisting of other elements. The natural location of heavy objects was the center of the Earth, which was considered the center of the universe. The element “fire” was endowed with the least amount of “heaviness”; Moreover, fire was characterized by a kind of negative gravity, the effect of which was manifested not in gravity, but in “levitation.” The natural place for fire was the outer boundaries of the earthly part of the world. Recent versions of this theory postulated the existence of a fifth entity (the "quintessence", sometimes called "ether", which was free from the effects of gravity). It was also postulated that celestial bodies consist of quintessence. If the earthly body somehow found itself not in its natural place, then it sought to return there through natural movement, characteristic of it in the same way as an animal is characterized by purposeful movement with the help of legs or wings. The above applies to the movement of a stone in space, a bubble in water and a flame in air.

Galileo (1564–1642), studying the motion of bodies under the influence of gravity, discovered that the period of oscillation of a pendulum does not depend on whether the initial deviation of the pendulum from the equilibrium position was large or small. Galileo also experimentally established that in the absence of air resistance, heavy and light bodies fall to the ground with the same acceleration. (Aristotle argued that heavy bodies fall faster than light ones, and the faster the heavier they are.) Finally, Galileo expressed the idea of the constancy of the acceleration of gravity and formulated statements that are essentially the predecessors of Newton's laws of motion. It was Galileo who was the first to understand that for a body on which no forces act, uniform linear motion is as natural as a state of rest.

It fell to the brilliant English mathematician I. Newton (1643–1727) to unite the disparate fragments and build a logical and consistent theory. These scattered fragments were created through the efforts of many researchers. Here is the heliocentric theory of Copernicus, perceived by Galileo, Kepler and others as a genuine physical model of the world; and Brahe's detailed and precise astronomical observations; and the concentrated expression of these observations in Kepler's three laws of planetary motion; and the work begun by Galileo to formulate the laws of mechanics on the basis of clearly defined concepts, as well as hypotheses and partial solutions to problems found by Newton's contemporaries such as H. Huygens, R. Hooke and E. Halley. To achieve his magnificent synthesis, Newton needed to complete the creation of a new mathematics, called differential and integral calculus. In parallel with Newton, his contemporary G. Leibniz worked independently on the creation of differential and integral calculus.

Although Voltaire's anecdote about an apple falling on Newton's head is most likely untrue, it nevertheless characterizes to some extent the type of thinking that Newton demonstrated in his approach to the problem of gravity. Newton persistently asked the questions: “Is the force that keeps the Moon in its orbit as it moves around the Earth the same force that causes bodies to fall to the Earth’s surface? How intense would Earth's gravity have to be to bend the Moon's orbit the way it actually does? To find an answer to these questions, Newton needed first of all to define the concept of force, which would also cover the factor that causes a body to deviate from its original trajectory of motion, and not just accelerate or decelerate when moving up or down. Newton also needed to know exactly the size of the Earth and the distance from the Earth to the Moon. He assumed that the attraction created by gravity decreases with increasing distance from the attracting body as the inverse square of the distance, i.e. as the distance increases. The truth of this conclusion for circular orbits can easily be deduced from Kepler's laws without resorting to differential calculus. Finally, when in the 1660s Piccard carried out a geodetic survey of the northern regions of France (one of the first geodetic surveys), he was able to clarify the value of the length of one degree of latitude on the earth's surface, which made it possible to more accurately determine the size of the Earth and the distance from the Earth to the Moon. Picard's measurements further strengthened Newton's belief that he was on the right track. Finally, in 1686–1687, in response to a request from the recently formed Royal Society, Newton published his famous Mathematical principles of natural philosophy (Philosophiae naturalis principia mathematica), which marked the birth of modern mechanics. In this work, Newton formulated his famous law of universal gravitation; in modern algebraic notation this law is expressed by the formula

Where F– the force of attraction between two material bodies with masses M 1 and M 2, a R– the distance between these bodies. Coefficient G called the gravitational constant. In the metric system, mass is measured in kilograms, distance is measured in meters, and force is measured in newtons and the gravitational constant G has the meaning G= 6.67259H 10 –11 m 3 H kg –1 H s –2 . The smallness of the gravitational constant explains the fact that gravitational effects become noticeable only with a large mass of bodies.

Using the methods of mathematical analysis, Newton showed that a spherical body, for example the Moon, the Sun or a planet, creates gravity in the same way as a material point that is located in the center of the sphere and has an equivalent mass. Differential and integral calculus allowed both Newton himself and his followers to successfully solve new classes of problems, for example, the inverse problem of determining force from the uneven or curvilinear motion of a body moving under its influence; predict the speed and position of a body at any time in the future, if the force as a function of position is known; solve the problem of the total force of attraction of any body (not necessarily spherical) at any given point in space. New powerful mathematical tools have opened the way to solving many complex, previously unsolvable problems not only for gravitational, but also for other fields.

Newton also showed that, due to the 24-hour period of rotation around its own axis, the Earth should not have a strictly spherical, but somewhat flattened shape. The implications of Newton's research in this area lead us into the field of gravimetry, the science concerned with measuring and interpreting the force of gravity on the Earth's surface.

Long-range action.

However, in Newtonian Beginnings there is a space. The fact is that, having defined the force of gravity and given a mathematical expression describing it, Newton did not explain what gravity is and how it acts. Questions that have caused and continue to cause a lot of controversy since the 18th century. until recently, is as follows: how does a body located in one place (for example, the Sun) attract a body (for example, the Earth) located in another place, if there is no material connection between the bodies? How fast do gravitational effects travel? Instantly? At the speed of light and other electromagnetic oscillations or at some other speed? Newton did not believe in the possibility of action at a distance; he simply carried out calculations as if the law of inverse proportion to the square of distance was an accepted fact. Many, including Leibniz, Bishop Berkeley and the followers of Descartes, agreed with the Newtonian point of view, but were convinced that phenomena separated in space from the causes that cause them are unthinkable without some kind of physical mediating agent that completes the cause-and-effect relationship between them.

Later, all these and other questions were inherited by similar theories that explained the propagation of light. The luminous medium was called the ether, and, following earlier philosophers, in particular Descartes, physicists came to the conclusion that gravitational (as well as electrical and magnetic) forces are transmitted as a kind of pressure in the ether. And only when all attempts to formulate a consistent theory of the ether were unsuccessful, it became clear that although the ether provided an answer to the question of how action is carried out at a distance, this answer was not correct.

Field theory and relativity.

It fell to A. Einstein (1879–1955) to bring together scattered fragments of theories, expel the ether and postulate that in reality there is neither absolute space nor absolute time, since not a single experiment confirms their existence. In this his role was similar to that of Newton. To create his theory, Einstein, like Newton once, needed new mathematics - tensor analysis.

What Einstein was able to do is to some extent a consequence of the new way of thinking that developed throughout the 19th century. and associated with the emergence of the concept of field. A field, in the sense in which a modern theoretical physicist uses this term, is a region of idealized space in which, by indicating a certain coordinate system, the positions of points are specified along with a physical quantity or some set of quantities depending on these positions. When moving from one point in space to another, neighboring one, it should smoothly (continuously) decrease or increase, and can also change over time. For example, the speed of water in a river varies both with depth and from bank to bank; the temperature in the room is higher near the stove; the intensity (brightness) of illumination decreases with increasing distance from the light source. These are all examples of fields. Physicists consider fields to be real things. In support of their point of view, they appeal to the physical argument: the perception of light, heat or electric charge is as real as the perception of a physical object, the existence of which everyone is convinced of on the grounds that it can be touched, felt, or seen. In addition, experiments, for example, with scattered iron filings near a magnet, their alignment along a certain system of curved lines make the magnetic field directly perceptible to such an extent that no one will doubt that there is “something” around the magnet even after the iron filings are removed . Magnetic “field lines,” as Faraday called them, form a magnetic field.

So far we have avoided mentioning the gravitational field. Acceleration of gravity g on the surface of the Earth, which changes from point to point on the earth's surface and decreases with height, is such a field. But the great advance Einstein made was not manipulating the gravitational field of our everyday experience.

Instead of following Fitzgerald and Lorentz and considering the interaction between the ubiquitous ether and the measuring rods and clocks moving through it, Einstein introduced a physical postulate according to which any observer A who measures the speed of light using measuring rods and a watch that he carries with him will invariably get the same result c= 3H 10 8 m/s no matter how fast the observer is moving; any other observer's measuring rods IN, moving relative A with speed v, will look to the observer A reduced by times; observer's watch IN will look to the observer A walking several times slower; relations between observers A And IN are exactly reciprocal, so the observer's measuring rods A and his watch will be for the observer IN respectively, equally shorter and moving more slowly; Each of the observers can consider himself motionless and the other moving. Another consequence of the partial (special) theory of relativity was that mass m body moving at speed v relative to the observer, increases (for the observer) and becomes equal to , where m 0 – mass of the same body, moving relative to the observer very slowly. The increase in the inertial mass of a moving body meant that not only the energy of motion (kinetic energy), but all energy has inertial mass and that if energy has inertial mass, then it also has heavy mass and, therefore, is subject to gravitational effects. In addition, as is now well known, under certain conditions, mass can be converted into energy in nuclear processes. (It would probably be more accurate to talk about the release of energy.) If the accepted assumptions are correct (and now we have every reason for such confidence), then, therefore, mass and energy are different aspects of the same more fundamental essence.

The above formula also indicates that not a single material body and not a single energy-carrying object (for example, a wave) can move relative to the observer faster than the speed of light With, because otherwise such movement would require infinitely more energy. Consequently, gravitational effects must propagate at the speed of light (arguments in favor of this were given even before the creation of the theory of relativity). Examples of such gravitational phenomena were later discovered and included in the general theory.

In the case of uniform and rectilinear relative motion, the observed contractions of the measuring rods and the slowing down of the clock lead to the special theory of relativity. Later, the concepts of this theory were generalized to accelerated relative motion, which required introducing another postulate - the so-called equivalence principle, which made it possible to include gravity in the model, which was absent in the partial theory of relativity.

For a long time it was believed, and very careful measurements made at the end of the 19th century. Hungarian physicist L. Eotvos confirmed that, within the limits of experimental error, heavy and inert masses are numerically equal. (Recall that the heavy mass of a body serves as a measure of the force with which this body attracts other bodies, while inertial mass is a measure of the body’s resistance to acceleration.) At the same time, the acceleration of freely falling bodies would not be completely independent of their mass if the inertia and heavy body weights were not absolutely equal. Einstein postulated that these two types of mass, which appear different because they are measured in different experiments, are actually the same thing. It immediately follows that there is no physical difference between the force of gravity, which we feel on the soles of our feet, and the force of inertia, which throws us back into the seat when a car accelerates, or throws us forward when we press the brakes. Let us mentally imagine (as Einstein did) a closed room, such as an elevator or a spaceship, inside which we can study the motion of bodies. In outer space, at a sufficiently large distance from any massive star or planet so that their gravity does not affect the bodies in this closed room, any object released from the hands would not fall to the floor, but would continue to float in the air, moving in the same direction , in which he was moving when he was released from his hands. All objects would have mass but no weight. In a gravitational field near the surface of the Earth, bodies have both mass and weight. If you let go of them, they fall to the ground. But if, for example, the elevator fell freely, without encountering any resistance, then the objects in the elevator would seem weightless to the observer in the elevator, and if he let go of any objects, they would not fall to the floor. The result would be the same as if everything happened in outer space far from attracting bodies, and no experiment could show the observer that he is in a state of free fall. Looking out the window and seeing the Earth somewhere far below him, the observer could say that the Earth is rushing towards him. However, from the point of view of an observer on Earth, both the elevator and all the objects in it fall equally quickly, so the falling objects do not lag behind or ahead of the elevator, and therefore do not approach its floor, towards which they fall.

Now let's imagine a spaceship being lifted into space by a launch vehicle at an ever-increasing speed. If an astronaut in a spaceship releases an object from his hands, then the object (as before) will continue to move through space at the speed with which it was released, but since the floor of the spaceship is now moving accelerated towards the object, everything will look as if the object would fall. Moreover, the astronaut would feel a force acting on his legs and could interpret it as the force of gravity, and no experiment he could perform while in a rising spacecraft would contradict such an interpretation.

Einstein's principle of equivalence simply equates these two seemingly completely different situations and states that gravity and inertial forces are the same thing. The main difference is that in a large enough region, the inertial force (such as centrifugal force) can be eliminated by a suitable transformation of the reference frame (for example, centrifugal force only acts in a rotating coordinate system, and can be eliminated by moving to a non-rotating reference frame). As for the force of gravity, by moving to another frame of reference (freely falling), one can only get rid of it locally. Mentally imagining the entire Earth as a whole, we prefer to consider it motionless, believing that bodies located on the surface of the Earth are acted upon by gravitational forces, and not by inertial forces. Otherwise, we would have to assume that the surface of the Earth is accelerated outward at all its points and that the Earth, expanding like an inflated balloon, presses on the soles of our feet. This point of view, quite acceptable from the point of view of dynamics, is incorrect from the point of view of ordinary geometry. However, within the framework of the general theory of relativity, both points of view are equally acceptable.

The geometry resulting from the measurement of lengths and time intervals, freely transformable from one accelerating frame of reference to another, turns out to be a curved geometry, very similar to the geometry of spherical surfaces, but generalized to the case of four dimensions - three spatial and one time - in the same way, as in the special theory of relativity. The curvature, or deformation, of space-time is not just a figure of speech, but something more, since it is determined by the method of measuring distances between points and the duration of time intervals between events at these points. That the curvature of spacetime is a real physical effect can best be demonstrated by a few examples.

According to the theory of relativity, a ray of light passing near a large mass is bent. This happens, for example, with a ray of light from a distant star passing near the edge of the solar disk. But a curved ray of light continues to be the shortest distance from the star to the observer’s eye. This statement is true in two senses. In the traditional notation of relativistic mathematics, a straight line segment dS, separating two neighboring points, is calculated using the Pythagorean theorem of ordinary Euclidean geometry, i.e. according to the formula dS 2 = dx 2 + dy 2 + dz 2. A point in space together with a moment in time is called an event, and the distance in space-time separating two events is called an interval. To determine the interval between two events, the time dimension t combines with three spatial coordinates x, y, z in the following way. Time difference between two events dt converted to spatial distance With H dt multiplied by the speed of light With(constant for all observers). The result obtained should be compatible with the Lorentz transformation, from which it follows that the measuring rod of a moving observer contracts, and the clock slows down according to the expression . The Lorentz transformation should also be applicable in the limiting case when the observer moves with the light wave and his clock is stopped (i.e. dt= 0), and he himself does not consider himself moving (i.e. dS= 0), so

(Interval) 2 = dS 2 = dx 2 + dy 2 + dz 2 – (c H dt) 2 .

The main feature of this formula is that the sign of the time term is opposite to the sign of the spatial terms. Further, along the light beam for all observers moving along with the beam, we have dS 2 = 0 and, according to the theory of relativity, all other observers should have obtained the same result. In this first (spatio-temporal) sense dS– minimum space-time distance. But in the second sense, since light travels along the path that requires the least time to reach its final destination according to any hours, the numerical values of spatial and time intervals are minimal for the light beam.

All the above considerations refer to events separated only by small distances and times; in other words, dx, dy, dz And dt– small quantities. But the results can be easily generalized to extended trajectories using the method of integral calculus, the essence of which is the summation of all these infinitesimal intervals along the entire path from point to point.

Reasoning further, let's mentally imagine space-time divided into four-dimensional cells, just as a two-dimensional map is divided into two-dimensional squares. The side of such a four-dimensional cell is equal to a unit of time or distance. In a field-free space, the grid consists of straight lines intersecting at right angles, but in a gravitational field near the mass, the grid lines are bent, although they also intersect at right angles, like parallels and meridians on a globe. In this case, the grid lines appear curved only to an external observer whose number of dimensions is greater than the number of grid measurements. We exist in three-dimensional space and when we look at a map or diagram, we can perceive it in three dimensions. A subject located in this grid itself, for example a microscopic creature on a globe, who has no idea what up or down is, cannot perceive the curvature of the globe directly and would have to make measurements and see what kind of geometry arises from the totality of the results dimensions - whether it be Euclidean geometry, corresponding to a flat sheet of paper, or curved geometry, corresponding to the surface of a sphere or some other curved surface. In the same way, we cannot see the curvature of the space-time around us, but by analyzing the results of our measurements, we can discover special geometric properties that are exactly similar to real curvature.

Now imagine a huge triangle in free space, the sides of which are three straight lines. If a mass is placed inside such a triangle, then the space (i.e., the four-dimensional coordinate grid revealing its geometric structure) will slightly inflate so that the sum of the interior angles of the triangle becomes greater than in the absence of mass. Similarly, you can imagine a giant circle in free space, the length and diameter of which you have very accurately measured. You discovered that the ratio of the circumference to the diameter is equal to the number p(if the free space is Euclidean). Place a large mass in the center of the circle and repeat the measurements. The ratio of circumference to diameter will become smaller p, although the measuring rod (if viewed from some distance) will appear to contract both when it is laid along the circumference and when it is laid along the diameter, the magnitude of the contractions themselves will be different.

In curvilinear geometry, a curve that connects two points and is the shortest among all curves of this kind is called a geodesic. In the four-dimensional curvilinear geometry of general relativity, the trajectories of light rays form one class of geodesics. It turns out that the trajectory of any free particle (which is not affected by any contact force) is also a geodesic, but of a more general class. For example, a planet freely moving in its orbit around the Sun moves along a geodesic in the same way as the freely falling elevator in the example discussed earlier. Geodesics are the space-time analogues of straight lines in Newtonian mechanics. Bodies simply move along their natural curved paths—the lines of least resistance—so that there is no need to invoke “force” to explain this behavior of the body. Bodies located on the surface of the Earth are subject to the contact force of direct contact with the Earth, and from this point of view we can assume that the Earth pushes them out of geodetic orbits. Consequently, the trajectories of bodies on the Earth's surface are not geodesic.

So, gravity was reduced to a geometric property of physical space, and the gravitational field turned out to be replaced by a “metric field”. Like other fields, a metric field is a set of numbers (ten in total) that vary from point to point and together describe the local geometry. Using these numbers, in particular, it is possible to determine how and in what direction the metric field is curved.

Consequences from the general theory of relativity.

Another prediction of general relativity resulting from the equivalence principle is the so-called gravitational redshift, i.e. a decrease in the frequency of radiation coming to us from an area with a lower gravitational potential. Although there are numerous suggestions in the literature that the red-shifted light was emitted from the surface of super-dense stars, there is still no convincing evidence for this, and the question remains open. The effect of such a displacement was actually observed in laboratory conditions - between the top and base of the tower. These experiments used the Earth's gravitational field and strictly monochromatic gamma radiation emitted by atoms bound in a crystal lattice (the Mössbauer effect). To explain this phenomenon, the easiest way is to turn to a hypothetical elevator, in which a light source is placed at the top and a receiver at the bottom, or vice versa. The observed shift exactly coincides with the Doppler shift, corresponding to the additional speed of the receiver at the moment of arrival of the signal compared to the speed of the source at the moment of emission of the signal. This extra speed is due to the acceleration while the signal is in transit.

Another almost immediately accepted prediction of general relativity concerns the motion of the planet Mercury around the Sun (and, to a lesser extent, the motion of other planets). Perihelion of Mercury's orbit, i.e. the point in its orbit at which the planet is closest to the Sun shifts by 574I per century, completing a full revolution in 226,000 years. Newtonian mechanics, taking into account the gravitational action of all known planets, was able to explain the perihelion shift by only 532І per century. The difference of 42 arcseconds, although small, is still much larger than any possible error, and has plagued astronomers for almost a century. General relativity predicted this effect almost exactly.

Revival of Mach's views on inertia.

E. Mach (1838–1916), like Newton’s younger contemporary Berkeley, repeatedly asked himself the question: “What explains inertia? Why does a centrifugal reaction occur when a body rotates?” In search of an answer to these questions, Mach suggested that inertia is due to the gravitational coherence of the Universe. Each particle of matter is united with all other matter in the Universe by gravitational bonds, the intensity of which is proportional to its mass. Therefore, when a force applied to a particle accelerates it, the gravitational bonds of the Universe as a whole resist this force, creating an inertial force of equal magnitude and opposite direction. At a later time, the question raised by Mach was revived and took on a new twist: if there is neither absolute motion nor absolute linear acceleration, then is it possible to exclude absolute rotation? The state of affairs is such that rotation relative to the outside world can be detected in an isolated laboratory without direct reference to the outside world. This can be done by centrifugal forces (forcing the surface of the water in a rotating bucket to take a concave shape) and Coriolis forces (creating an apparent curvature of the body’s trajectory in a rotating coordinate system. Of course, imagining a small rotating body is incomparably easier than a rotating Universe. But the question is this: If the rest of the universe disappeared, how could we judge whether a body was rotating "absolutely"? Would the surface of the water in the bucket remain concave? Would the rotating weight create tension in the rope? Mach believed that the answers to these questions must be negative. If Since gravity and inertia are interrelated, one would expect that changes in the density or distribution of distant matter would somehow affect the value of the gravitational constant G. For example, if the Universe is expanding, then the value G should change slowly over time. Change in value G could affect the periods of oscillation of the pendulum and the revolution of the planets around the Sun. Such changes can only be detected by measuring time intervals using atomic clocks, the rate of which does not depend on G.

Measuring the gravitational constant.

Experimental determination of the gravitational constant G allows us to establish a bridge between the theoretical and abstract aspects of gravity as a universal attribute of matter and the more earthly question of its localization and assessment of the mass of matter creating gravitational effects. The last operation is sometimes called weighing. From a theoretical point of view, we have already seen that G is one of the fundamental constants of nature and is therefore of paramount importance for physical theory. But the magnitude G must also be known if we want to detect and “weigh” matter on the basis of the gravitational effect that it creates.

According to Newton's law of universal gravitation, the acceleration of any test body in the gravitational field of another body with mass m is given by the formula g = Gm/r 2 where r– distance from the body with mass m. Factors in astronomical equations of motion G And m included only in the form of a work Gm, but are never included separately. This means that the mass m, which creates acceleration, can be estimated only if the value is known G. But based on the mass ratios, it is possible, by comparing the accelerations they produce, to express the masses of the planets and the Sun in terrestrial masses. Indeed, if two bodies create accelerations g 1 and g 2, then the ratio of their masses is m 1 /m 2 = g 1 r 1 2 /g 2 r 2 2 . This makes it possible to express the masses of all celestial bodies through the mass of one selected body, for example the Earth. This procedure is equivalent to choosing the mass of the Earth as a mass standard. To move from this procedure to the centimeter–gram–second system of units, you need to know the mass of the Earth in grams. If it is known, then we can calculate G, having found the work Gm from any equation that describes the gravitational effects created by the Earth (for example, the movement of the Moon or an artificial satellite of the Earth, the oscillations of a pendulum, the acceleration of a body in free fall). And vice versa, if G can be measured independently, then the product Gm, included in all equations of motion of celestial bodies, will give the mass of the Earth. These considerations made it possible to experimentally estimate G. An example is Cavendish's famous experiment with torsion balances, carried out in 1798. The installation consisted of two small masses at the ends of a balanced rod, attached in the middle to a long thread of a torsion bar suspension. Two other, larger masses are mounted on a rotating stand so that they can be brought to the small masses. The attraction acting from the larger masses on the smaller ones, although much weaker than the attraction of such a large mass as the Earth, turns the rod on which the small masses are fixed, and twists the thread of the suspension to an angle that can be measured. By then bringing larger masses to smaller ones on the other side (so that the direction of attraction changes), the displacement can be doubled and thus the accuracy of the measurement can be increased. The torsional modulus of elasticity of the thread is assumed to be known, since it can be easily measured in the laboratory. Therefore, by measuring the angle of twist of the thread, it is possible to calculate the force of attraction between the masses.

Literature:

Fock V.A. Theory of space, time and gravity. M., 1961
Zeldovich Ya.B., Novikov I.D. The theory of gravity and the evolution of stars. M., 1971
Weiskopf W. Physics in the twentieth century. M., 1977
Albert Einstein and the theory of gravity. M., 1979

Between all material bodies. In the approximation of low speeds and weak gravitational interaction, it is described by Newton’s theory of gravity, in the general case it is described by Einstein’s general theory of relativity. In the quantum limit, gravitational interaction is supposedly described by a quantum theory of gravity, which has not yet been developed.

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Subtitles

Gravitational attraction

The law of universal gravitation is one of the applications of the inverse square law, which is also found in the study of radiation (see, for example, Light Pressure), and is a direct consequence of the quadratic increase in the area of the sphere with increasing radius, which leads to a quadratic decrease in the contribution of any unit area to area of the entire sphere.

The gravitational field, like the field of gravity, is potential. This means that you can introduce the potential energy of gravitational attraction of a pair of bodies, and this energy will not change after moving the bodies along a closed loop. The potentiality of the gravitational field entails the law of conservation of the sum of kinetic and potential energy and, when studying the motion of bodies in a gravitational field, often significantly simplifies the solution. Within the framework of Newtonian mechanics, gravitational interaction is long-range. This means that no matter how a massive body moves, at any point in space the gravitational potential depends only on the position of the body at a given moment in time.

Large space objects - planets, stars and galaxies have enormous mass and, therefore, create significant gravitational fields.

Gravity is the weakest interaction. However, since it acts at all distances and all masses are positive, it is nevertheless a very important force in the Universe. In particular, the electromagnetic interaction between bodies on a cosmic scale is small, since the total electric charge of these bodies is zero (matter as a whole is electrically neutral).

Also, gravity, unlike other interactions, is universal in its effect on all matter and energy. No objects have been discovered that have no gravitational interaction at all.

Due to its global nature, gravity is responsible for such large-scale effects as the structure of galaxies, black holes and the expansion of the Universe, and for elementary astronomical phenomena - the orbits of planets, and for simple attraction to the surface of the Earth and the fall of bodies.

Gravity was the first interaction described by mathematical theory. Aristotle (IV century BC) believed that objects with different masses fall at different speeds. And only much later (1589) Galileo Galilei experimentally determined that this is not so - if air resistance is eliminated, all bodies accelerate equally. Isaac Newton's law of universal gravitation (1687) described the general behavior of gravity well. In 1915, Albert Einstein created the General Theory of Relativity, which more accurately describes gravity in terms of the geometry of spacetime.

Celestial mechanics and some of its tasks

The simplest problem of celestial mechanics is the gravitational interaction of two point or spherical bodies in empty space. This problem within the framework of classical mechanics is solved analytically in a closed form; the result of its solution is often formulated in the form of Kepler's three laws.

As the number of interacting bodies increases, the task becomes dramatically more complicated. Thus, the already famous three-body problem (that is, the motion of three bodies with non-zero masses) cannot be solved analytically in a general form. With a numerical solution, instability of the solutions relative to the initial conditions occurs quite quickly. When applied to the Solar System, this instability does not allow us to accurately predict the motion of planets on scales exceeding a hundred million years.

In some special cases, it is possible to find an approximate solution. The most important is the case when the mass of one body is significantly greater than the mass of other bodies (examples: the Solar system and the dynamics of the rings of Saturn). In this case, as a first approximation, we can assume that light bodies do not interact with each other and move along Keplerian trajectories around the massive body. The interactions between them can be taken into account within the framework of perturbation theory and averaged over time. In this case, non-trivial phenomena may arise, such as resonances, attractors, chaos, etc. A clear example of such phenomena is the complex structure of the rings of Saturn.

Despite attempts to accurately describe the behavior of a system of a large number of attracting bodies of approximately the same mass, this cannot be done due to the phenomenon of dynamic chaos.

Strong gravitational fields

In strong gravitational fields, as well as when moving in a gravitational field at relativistic speeds, the effects of general relativity (GTR) begin to appear:

changing the geometry of space-time;
- as a consequence, the deviation of the law of gravity from Newtonian;
- and in extreme cases - the emergence of black holes;
delay of potentials associated with the finite speed of propagation of gravitational disturbances;
- as a consequence, the appearance of gravitational waves;
nonlinearity effects: gravity tends to interact with itself, so the principle of superposition in strong fields no longer holds.

Gravitational radiation

One of the important predictions of General Relativity is gravitational radiation, the presence of which was confirmed by direct observations in 2015. However, before there was strong indirect evidence in favor of its existence, namely: energy losses in close binary systems containing compact gravitating objects (such as neutron stars or black holes), in particular, in the famous system PSR B1913+16 (Hals pulsar - Taylor) - are in good agreement with the general relativity model, in which this energy is carried away precisely by gravitational radiation.

Gravitational radiation can only be generated by systems with variable quadrupole or higher multipole moments; this fact suggests that the gravitational radiation of most natural sources is directional, which significantly complicates its detection. Gravity power n-field source is proportional (v / c) 2 n + 2 (\displaystyle (v/c)^(2n+2)), if the multipole is of electric type, and (v / c) 2 n + 4 (\displaystyle (v/c)^(2n+4))- if the multipole is of magnetic type, where v is the characteristic speed of movement of sources in the radiating system, and c- speed of light. Thus, the dominant moment will be the quadrupole moment of the electric type, and the power of the corresponding radiation is equal to:

L = 1 5 G c 5 ⟨ d 3 Q i j d t 3 d 3 Q i j d t 3 ⟩ , (\displaystyle L=(\frac (1)(5))(\frac (G)(c^(5)))\ left\langle (\frac (d^(3)Q_(ij))(dt^(3)))(\frac (d^(3)Q^(ij))(dt^(3)))\right \rangle ,)

Where Q i j (\displaystyle Q_(ij))- quadrupole moment tensor of the mass distribution of the radiating system. Constant G c 5 = 2.76 × 10 − 53 (\displaystyle (\frac (G)(c^(5)))=2.76\times 10^(-53))(1/W) allows us to estimate the order of magnitude of the radiation power.

Since 1969 (Weber's experiments (English)), attempts are being made to directly detect gravitational radiation. In the USA, Europe and Japan there are currently several operating ground-based detectors (LIGO, VIRGO, TAMA (English), GEO 600), as well as the LISA (Laser Interferometer Space Antenna) space gravitational detector project. A ground-based detector in Russia is being developed at the Dulkyn Scientific Center for Gravitational Wave Research in the Republic of Tatarstan.

Subtle effects of gravity

In addition to the classical effects of gravitational attraction and time dilation, the general theory of relativity predicts the existence of other manifestations of gravity, which under terrestrial conditions are very weak and therefore their detection and experimental verification are very difficult. Until recently, overcoming these difficulties seemed beyond the capabilities of experimenters.

Among them, in particular, one can name the drag of inertial reference frames (or the Lense-Thirring effect) and the gravitomagnetic field. In 2005, NASA's unmanned Gravity Probe B conducted an unprecedented precision experiment to measure these effects near Earth. Processing of the obtained data was carried out until May 2011 and confirmed the existence and magnitude of the effects of geodetic precession and drag of inertial reference systems, although with an accuracy somewhat less than originally assumed.

After intensive work to analyze and extract measurement noise, the final results of the mission were announced at a press conference on NASA-TV on May 4, 2011, and published in Physical Review Letters. The measured value of geodetic precession was −6601.8±18.3 milliseconds arcs per year, and the entrainment effect - −37.2±7.2 milliseconds arcs per year (compare with theoretical values of −6606.1 mas/year and −39.2 mas/year).

Classical theories of gravity

Due to the fact that quantum effects of gravity are extremely small even under the most extreme and observational conditions, there are still no reliable observations of them. Theoretical estimates show that in the vast majority of cases one can limit oneself to the classical description of gravitational interaction.

There is a modern canonical classical theory of gravity - the general theory of relativity, and many clarifying hypotheses and theories of varying degrees of development, competing with each other. All of these theories make very similar predictions within the approximation in which experimental tests are currently carried out. The following are several basic, most well-developed or known theories of gravity.

General theory of relativity

However, general relativity has been confirmed experimentally until very recently (2012). In addition, many alternative approaches to Einstein's, but standard for modern physics, approaches to the formulation of the theory of gravity lead to a result coinciding with general relativity in the low-energy approximation, which is the only one now accessible to experimental verification.

Einstein-Cartan theory

A similar division of equations into two classes also occurs in the RTG, where the second tensor equation is introduced to take into account the connection between non-Euclidean space and Minkowski space. Thanks to the presence of a dimensionless parameter in the Jordan-Brans-Dicke theory, it becomes possible to choose it so that the results of the theory coincide with the results of gravitational experiments. Moreover, as the parameter tends to infinity, the predictions of the theory become closer and closer to general relativity, so it is impossible to refute the Jordan-Brans-Dicke theory by any experiment confirming the general theory of relativity.

Quantum theory of gravity

Despite more than half a century of attempts, gravity is the only fundamental interaction for which a generally accepted consistent quantum theory has not yet been constructed. At low energies, in the spirit of quantum field theory, the gravitational interaction can be represented as an exchange of gravitons - spin-2 gauge bosons. However, the resulting theory is non-renormalizable, and is therefore considered unsatisfactory.

In recent decades, several promising approaches to solving the problem of quantization of gravity have been developed: string theory, loop quantum gravity, and others.

String theory

In it, instead of particles and background space-time, strings and their multidimensional analogues appear -

In general, it is described by Einstein's general theory of relativity. In the quantum limit, gravitational interaction is supposedly described by a quantum theory of gravity, which has not yet been developed.

Gravity plays an extremely important role in the structure and evolution of the Universe (establishing a connection between the density of the Universe and the rate of its expansion), determining the key conditions for the equilibrium and stability of astronomical systems. Without gravity, there would be no planets, stars, galaxies, or black holes in the Universe.

Gravitational attraction

Law of Gravity

The gravitational field, like the gravity field, is potential. This means that you can introduce the potential energy of gravitational attraction of a pair of bodies, and this energy will not change after moving the bodies along a closed loop. The potentiality of the gravitational field entails the law of conservation of the sum of kinetic and potential energy and, when studying the motion of bodies in a gravitational field, often significantly simplifies the solution. Within the framework of Newtonian mechanics, gravitational interaction is long-range. This means that, no matter how massive a body moves, at any point in space the gravitational potential depends only on the position of the body at a given moment in time.

Large space objects - planets, stars and galaxies have enormous mass and, therefore, create significant gravitational fields.

Also, gravity, unlike other interactions, is universal in its effect on all matter and energy. No objects have been discovered that have no gravitational interaction at all.

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Celestial mechanics and some of its tasks

As the number of interacting bodies increases, the task becomes dramatically more complicated. Thus, the already famous three-body problem (that is, the motion of three bodies with non-zero masses) cannot be solved analytically in a general form. With a numerical solution, instability of the solutions relative to the initial conditions occurs quite quickly. When applied to the solar system, this instability does not allow us to accurately predict the motion of planets on scales exceeding a hundred million years.

Despite attempts to accurately describe the behavior of a system of a large number of attracting bodies of approximately the same mass, this cannot be done due to the phenomenon of dynamic chaos.

Strong gravitational fields

In strong gravitational fields (as well as when moving in a gravitational field at relativistic speeds), the effects of the general theory of relativity (GTR) begin to appear:

changing the geometry of space-time;
- as a consequence, the deviation of the law of gravity from Newtonian;
- and in extreme cases - the emergence of black holes;
delay of potentials associated with the finite speed of propagation of gravitational disturbances;
- as a consequence, the appearance of gravitational waves;
nonlinearity effects: gravity tends to interact with itself, so the principle of superposition in strong fields no longer holds.

Gravitational radiation

One of the important predictions of General Relativity is gravitational radiation, the presence of which was confirmed by direct observations in 2015. However, there was previously strong indirect evidence in favor of its existence, namely: energy losses in close binary systems containing compact gravitating objects (such as neutron stars or black holes), in particular, discovered in 1979 in the famous system PSR B1913+16 (Hulse-Taylor pulsar) - are in good agreement with the general relativity model, in which this energy is carried away precisely by gravitational radiation.

Gravitational radiation can only be generated by systems with variable quadrupole or higher multipole moments, this fact suggests that the gravitational radiation of most natural sources is directional, which significantly complicates its detection. Gravity power n (\displaystyle n)-field source is proportional (v / c) 2 n + 2 (\displaystyle (v/c)^(2n+2)), if the multipole is of electric type, and (v / c) 2 n + 4 (\displaystyle (v/c)^(2n+4))- if the multipole is of magnetic type, where v (\displaystyle v) is the characteristic speed of movement of sources in the radiating system, and c (\displaystyle c)- speed of light in vacuum. Thus, the dominant moment will be the quadrupole moment of the electric type, and the power of the corresponding radiation is equal to:

L = 1 5 G c 5 ⟨ d 3 Q i j d t 3 d 3 Q i j d t 3 ⟩ , (\displaystyle L=(\frac (1)(5))(\frac (G)(c^(5)))\ left\langle (\frac (d^(3)Q_(ij))(dt^(3)))(\frac (d^(3)Q^(ij))(dt^(3)))\right \rangle ,)

Subtle effects of gravity

Measuring the curvature of space in Earth's orbit (artist's drawing)

Among them, in particular, we can name the drag of inertial reference frames (or the Lense-Thirring effect) and the gravitomagnetic field. In 2005, NASA's robotic Gravity Probe B conducted an unprecedented precision experiment to measure these effects near Earth. Processing of the obtained data was carried out until May 2011 and confirmed the existence and magnitude of the effects of geodetic precession and drag of inertial reference systems, although with an accuracy somewhat less than originally assumed.

Classical theories of gravity

General theory of relativity

Einstein-Cartan theory

Quantum theory of gravity

Despite more than half a century of attempts, gravity is the only fundamental interaction for which a generally accepted consistent quantum theory has not yet been constructed. At low energies, in the spirit of quantum field theory, the gravitational interaction can be thought of as an exchange of gravitons—spin 2 gauge bosons. However, the resulting theory is non-renormalizable, and is therefore considered unsatisfactory.

In recent decades, several promising approaches to solving the problem of quantizing gravity have been developed: string theory, loop quantum gravity, and others.

String theory

In it, instead of particles and background space-time, strings and their multidimensional analogues - branes appear. For high-dimensional problems, branes are high-dimensional particles, but from the point of view of particles moving inside these branes, they are space-time structures. A variant of string theory is M-theory.

Loop quantum gravity

It attempts to formulate a quantum field theory without reference to the space-time background; according to this theory, space and time consist of discrete parts. These small quantum cells of space are connected to each other in a certain way, so that on small scales of time and length they create a motley, discrete structure of space, and on large scales they smoothly transform into continuous smooth space-time. While many cosmological models can only describe the behavior of the universe from Planck time after the Big Bang, loop quantum gravity can describe the explosion process itself, and even look further back. Loop quantum gravity allows us to describe all particles of the standard model without requiring the introduction of the Higgs boson to explain their masses.

Causal dynamic triangulation

Causal dynamic triangulation - the space-time manifold in it is built from elementary Euclidean simplexes (triangle, tetrahedron, pentachore) of dimensions on the order of Planckian ones, taking into account the principle of causality. The four-dimensionality and pseudo-Euclidean nature of space-time on macroscopic scales are not postulated in it, but are a consequence of the theory.

Gravity in microcosm

Gravity in the microcosm at low energies of elementary particles is many orders of magnitude weaker than other fundamental interactions. Thus, the ratio of the force of gravitational interaction of two protons at rest to the force of electrostatic interaction is equal to 10 − 36 (\displaystyle 10^(-36)).

To compare the law of universal gravitation with Coulomb’s law, the value G N m (\displaystyle (\sqrt (G_(N)))m) called gravitational charge. Due to the principle of equivalence of mass and energy gravitational charge equals G N E c 2 (\displaystyle (\sqrt (G_(N)))(\frac (E)(c^(2)))). The gravitational interaction becomes equal in strength to the electromagnetic one when the gravitational charge is equal to the electric charge G N E c 2 = e (\displaystyle (\sqrt (G_(N)))(\frac (E)(c^(2)))=e), that is, at energies E = e c 2 G N = 10 18 (\displaystyle E=(\frac (ec^(2))(\sqrt (G_(N))))=10^(18)) GeV, so far unattainable in elementary particle accelerators.

Orff. gravity, -I Lopatin's spelling dictionary

gravity - -i, cf. 1. physical Mutual attraction between bodies with mass; gravity. The force of gravity. The law of universal gravitation. 2. Connection with someone or something. as with a center of influence; need for connection with someone or something. Economic attraction of the outskirts to the center. Small academic dictionary

GRAVITY - GRAVITY (gravity - gravitational interaction) - universal interaction between any types of physical matter (ordinary matter, any physical fields). Large encyclopedic dictionary

gravity - noun, number of synonyms... Dictionary of Russian synonyms

gravity - GRAVITY -I; Wed 1. Phys. The property of bodies and material particles to attract each other (depending on their mass and the distance between them); attraction, gravity. The force of gravity. The law of universal gravitation. 2. Attraction, desire for someone, something. Kuznetsov's Explanatory Dictionary

gravity - gravity cf. 1. The property of bodies to attract each other depending on their masses and the distance between them; attraction. 2. Attraction, desire for someone or something. 3. The need for connection with someone or something. 4. Oppression, overwhelming force, painful influence of someone or something. Explanatory Dictionary by Efremova

GRAVITY - (gravity, gravitational interaction), universal interaction between any types of matter. If this effect is relatively weak and the bodies move slowly (compared to the speed of light c), then Newton’s law of universal gravitation is valid. Physical encyclopedic dictionary

gravity - GRAVITY, I, cf. 1. The property of all bodies to attract each other, attraction (special). Terrestrial t. Newton's law of universal gravitation. 2. transfer, to someone or something. Attraction, desire for someone, need for something. T. to technology. To feel emotional about someone. Ozhegov's Explanatory Dictionary

gravity - Gravity, gravity, gravity, gravity, gravity, gravity, gravity, gravity, gravity, gravity, gravity, gravity Zaliznyak's Grammar Dictionary

gravitation - GRAVITY, gravitation, plural. no, cf. 1. Attraction; the inherent property of two material bodies to attract each other with a force directly proportional to the product of their masses and inversely proportional to the square of the distance between them (physical). Ushakov's Explanatory Dictionary

Gravity - Newton's law of universal gravity can be formulated as follows: every atom interacts with every other atom, while the force of interaction (attraction) is always directed along a straight line connecting the atoms... Encyclopedic Dictionary of Brockhaus and Efron