LECTURE 5 MODERN PHYSICAL PICTURE OF THE WORLD

Lecture plan:

1. Newtonian concept of absolute space and time. Laws of motion

2. Conservation laws

3. Principles of thermodynamics. Ideas about entropy

Questions of space and time have always interested human society. One of the concepts of these concepts comes from the ancient atomists - Democritus, Epicurus and others. They introduced the concept of empty space into scientific circulation and considered it as homogeneous and infinite.

In the process of creating a general picture of the universe, Isaac Newton (1642-1726), of course, also could not get around the issue of the concept of space and time.

According to Newton, the world consists of matter, space and time. These three categories are independent of each other. Matter is located in infinite space. The movement of matter occurs in space and time. Newton divided space into absolute and relative. Absolute space is motionless, infinite. The relative is part of the absolute. He also classified time. By absolute, true (mathematical) time, he understood time that flows always and everywhere uniformly, and relative time, according to Newton, is a measure of duration that exists in real life: second, minute, hour, day, month, year. For Newton, absolute time exists and lasts uniformly on its own, regardless of any events. Absolute space and absolute time are the receptacle of all material bodies and spaces and do not depend either on these bodies, or on these processes, or on each other.

Newton defines mass as the amount of matter and introduces the concept of "passive force" (force of inertia) and "active force" that creates the movement of bodies.

Having studied and revealed the laws of motion, Newton thus formulated his laws:

1st law. Any body should continue its state of rest or uniform rectilinear motion, since it is not forced by the applied forces to change this state.

2nd law. The change in motion must be proportional to the applied driving force and occur in the direction of the straight line along which this force acts.

3rd law. Action always meet equal opposition, or the impact of two bodies on each other be equal to each other and directed in opposite directions.

In our time, the famous laws are formulated in a more convenient form:

1. Any material body maintains a state of rest or uniform rectilinear motion until the impact from other bodies makes it change this state. The desire of the body to maintain a state of rest or uniform rectilinear motion is called inertia. Therefore, the first law is also called the law of inertia.

2. The acceleration acquired by the body is directly proportional to the force acting on the body, and inversely proportional to the mass of the body.

3. The forces with which interacting bodies act on each other are equal in magnitude and opposite in direction.

We know Newton's second law in the form

F=t a, or a= f/m ,

where is the acceleration a, received by the body under the influence of force F, inversely proportional to body weight t. Value t called the inertial mass of the body, it characterizes the body's ability to resist the acting ("active") force, that is, to maintain a state of rest. Newton's second law is valid only in inertial frames of reference.

The first law can be obtained from the second, since in the absence of other forces acting on the body, the acceleration is also zero. However, the first law is considered as an independent law, since it states the existence of inertial frames of reference.

Inertial frames of reference- these are systems in which the law of inertia is valid: a material point, when no forces act on it (or forces that are mutually balanced), is at rest or uniform rectilinear motion.

Theoretically, there can be arbitrarily equal inertial frames of reference, and in all such systems the laws of physics are the same. This asserts Galileo's principle of relativity (1636).

Scientific proof of the existence of universal gravitation and the mathematical expression of the law describing it became possible only on the basis of the laws of mechanics discovered by I. Newton. The law of universal gravitation was formulated by Newton in his work "The Mathematical Principles of Natural Philosophy" (1687).

Newton formulates the law of universal gravitation in the following theses: “gravitation exists for all bodies in general and is proportional to the mass of each of them”, “gravitation to separate equal particles of bodies is inversely proportional to the squares of the distances of places to particles”. This law is known as:

F=

where m 1 , m 2 - the masses of two particles, r- the distance between them, G- gravitational constant (in the SI system G= 6.672 10 -11 m 2 / kg 2). The physical meaning of the gravitational constant is that it characterizes the force of attraction of two masses weighing 1 kg at a distance of 1 m.

By discovering the law of universal gravitation, Newton was able to answer the question why the Moon revolves around the Earth and why the planets move around the Sun. In each individual case, he could calculate the force of gravity. But how the interaction between masses attracted to each other is transmitted, what is the nature of this force, Newton could not explain.

In the works of Newton, gravity is a force that acts at great distances and, as it were, without any material intermediary.

This led to the concept of "long-range action". Newton could not explain the nature of "long-range action". He thought about some kind of material "agent" through which the gravitational interaction is carried out, but in solving this problem he failed. Based on Newton's law of universal gravitation, celestial mechanics admits the fundamental possibility of instantaneous signal transmission, which contradicts modern physics ( general theory relativity). Therefore, a literal understanding of Newton's law of gravitation from a modern point of view is unacceptable.

The Newtonian mechanistic paradigm in natural science dominated for more than 200 years, although it was criticized in a number of positions, including in the understanding of space. and time (Leibniz, Hegel, Berkeley, etc.). At the end of the XIX and at the beginning of the XX century. fundamentally new scientific ideas about nature. New paradigms appeared: first relativistic and then quantum (see earlier). The concept of the field as a material medium that connects the particles of matter, all physical objects of the material world has rightfully entered the physical picture of the world. In modern physics, four types of interaction of material objects are known: electromagnetic, gravitational, strong and weak (see above). They are responsible for all interaction processes.

The section "Definitions" is the famous "Instruction", in which Newton sets out his views on space and time, relative and absolute motion. Newton is well aware that the movements observed in nature are of a relative nature: “movement and rest, in their usual consideration, differ only in relation to one another, because what appears to a simple look is not always at rest,” he says in explanation to "Definition III", and their description requires setting a frame of reference. But Newton believed that one could speak of the absolute motion of bodies, borrowing from Gassendi's ideas about absolute space and time. Here is how he defines these fundamental concepts in his mechanics:

"I/. Absolute, true mathematical time in itself and in its very essence, without any relation to anything external, flows evenly and is otherwise called duration.

Relative, apparent, or ordinary time is either exact or changeable, comprehended by the senses, external, accomplished through some kind of movement, a measure of duration used in everyday life instead of true mathematical time, such as: hour, day, month, year.

II. Absolute space by its very essence, regardless of anything external, always remains the same and immovable.

The relative is its measure, or some limited movable part, which is determined by our senses according to its position relative to certain bodies and which in everyday life is taken for an immovable space: for example, the extension of the spaces of underground air or aboveground, determined by their position relative to the Earth. Absolute and relative spaces are the same in form and size, but numerically they do not always remain the same. So, for example, if we consider the Earth as mobile, then the space of our air, which in relation to the Earth always remains the same, will now be one part of the absolute space, then another, depending on where the air has passed, and, therefore, absolutely the said space is constantly changing.

III. Place is the part of space occupied by the body, and in relation to space it can be either absolute or relative. I say "part of space" and not the position of the body and not the surface that surrounds it. For bodies of equal volume, the places are equal, while the surfaces can be unequal due to the dissimilarity of the shape of the bodies. A position, to put it correctly, has no magnitude, and it is not a place in itself, but a property belonging to a place. The movement of the whole is the same as the totality of the movements of its parts, i.e., the displacement of the whole from its place is the same as the totality of the displacements of its parts from their places, therefore the place of the whole is the same as the totality of the places of its parts, and, therefore , it is entirely inside the whole body.

IV. Absolute motion is the movement of a body from one absolute place to another, and relative motion from relative to relative.

Recognizing the objective existence of space and time, Newton takes a materialistic point of view. But, separating absolute space and time from real things and processes, Newton gives these categories a meta physical character. Absolute time is characterized, according to Newton, by the uniformity of the flow; for relative time comprehended in processes, for example, the movements of luminaries, such uniformity may not exist. “It is possible that there is no (in nature) such uniform motion by which time could be measured with perfect accuracy. Newton's absolute space is absolutely motionless space. “Just as the order of time is unchanging, so is the order of the parts of space. If they moved out of their places, they would move (so to speak) into themselves, for time and space are, as it were, containers of themselves and of everything that exists. In time, everything is arranged in the sense of the order of succession, in space, in the sense of the order of arrangement. In their very essence, they are places, and it is absurd to attribute movements to primary places. It is these places that are absolute places, and only movements from these places constitute absolute movements.

In practice, we are dealing with relative motions, linking frames of reference with certain bodies. “It may turn out that in reality there is no body at rest, to which the places and movements of others can be attributed.” Absolute time and space are incomprehensible to the senses and lose their physical character, turning into pure abstractions. It would be possible to manage in physical research even without these abstractions, operating with those spatio-temporal representations to which the study of real processes leads.

However, Newton believes that there are physical ways detection of absolute movements, i.e., movements of bodies in absolute space. It is impossible to detect the uniform rectilinear motion of the reference frame according to the classical principle of Galileo's relativity, which is also accepted by Newton. But it is possible to detect manifestations of the absolute motion of the system. Absolute motion differs from relative motion in that the applied forces actually change the absolute motion of the body, while the relative motion can change even without the action of forces on the body - it is enough only that the forces act on the surrounding bodies. If you hang a vessel with water on a rope and, having twisted the rope, give it the opportunity to unwind, then the following phenomena will be observed: the vessel begins to move, while the water is motionless, and its surface is flat. As the rope unwinds, the water also begins to rotate, and this will affect its level increase at the walls and decrease in the center - parts of the water move away from the axis of rotation. Thus, at the initial moment, the relative motion of the vessel and water was the greatest, but no manifestations of this relative motion of water were observed. Then the relative motion of the vessel and water decreased, the water began to rotate in the same way as the vessel, and this manifested itself in the removal of water particles from the axis of rotation. This is the desire of rotating bodies to move away from the axis of rotation and makes it possible to recognize absolute rotation. “In this way,” says Newton, “the quantity and direction of roundabout inside a huge empty space, where there would be no external signs accessible to the senses, to which the positions of the balls could be attributed. (Nyoton is talking about an imaginary experiment in studying the rotational motion of balls connected by a thread, the axis of rotation of which passes through the center of gravity of the balls. By the tension of the thread, one can ascertain whether the balls rotate or not.) If in this space, in addition, there were still some very remote bodies that maintain a relative position to each other, just like our fixed stars, then by the movement of the balls relative to these bodies we could not determine whether this movement belongs to the bodies or the balls. But if, having determined the tension of the thread, we found that this tension exactly corresponds to the motion of the balls, then we would conclude that the motion belongs to the balls, and not external bodies, and that these bodies are at rest.

Newton believes that the task of mechanics is "to find ... true movements but the causes that produce them, according to their manifestations and differences in apparent movements, and, conversely, to find their causes and manifestations from true or apparent movements." This is how the Newtonian concept of absolute space and time entered physics.

Absolute space.
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BUT. Absolute space in classical mechanics understood as existing in itself, independent of matter and time. The idea of ​​it was introduced by Gassendi and clarified by I. Newton as follows: it "regardless of anything external, always remains the same and immovable."

According to dialectical materialism, I. Newton understood space as objective, which corresponds to materialistic views, but as a completely independent entity, not associated with matter, which is metaphysics.

In the sense of Newest philosophy, absolute space according to Newton is the negation of any qualities (including relative spaces and their moments), therefore, firstly, it is like emptiness in its dialectical definition, but not directly it *, therefore, secondly , regardless and "remains always the same and motionless", and, thirdly, That's why(not on its own) is an(but does not exist) a “completely independent entity”, and not only irrelevant, but also not interacting with anything, and that is why the question of connection with matter really ... does not exist at all and cannot exist, but this is not metaphysics.
The following of absolute space as only-appearances for us explains the impossibility of its understanding and representation in materialism, in materialistic ideas and sciences, since for them there is no ... object of perception (there is a denial of any qualities) ** and, therefore, (scientific-cognitive) reflection in relation to it is not possible. So for materialism there really is no absolute space and cannot be; and good…

B. In this article, we note that absolute space in The latest philosophy understood as such very simple available space, which, as some non-immediate definiteness *** , is represented as a whole points of absolute rest[ontologically defined on the basis of physical phenomena], i.e. absolute space is, first, empty content, which gives an understanding of its irrelativity, immutability and its complete rest, and absolute space is not nothing, Secondly, biased by virtue of its complete simplicity, therefore it can be perceived metaphysically, moreover, for us it is idealized****. And therefore, Newton's conclusion that absolute space "regardless of anything external, always remains the same and motionless" is well understood. At the same time, it becomes clear why Newton was right in the well-known dispute with Leibniz: the arguments cited by Leibniz, as well as quantum fluctuations of vacuum discovered much later, simply have nothing to do with absolute space (for example, since any object in “absolutely empty space” (if it is there) is a closed system).
With some stretch, we can say that absolute space is a totality points of absolute rest, with respect to which (which) in spatial being everything is moving.
AT general case aggregates points of absolute rest can be related to the idealized Cartesian coordinate system, thereby setting three-dimensional set of points in absolute space.

Physical interpretation of the absolute space itself and fixation points of absolute rest are separate questions. However, it should be noted that even any housewife, using improvised objects, can create experimental conditions in which a number of points of absolute space can be accentuated. Another thing is that modern physics, blinded by materialistic ideas and the oppression of Einstein's SRT, is not able, it seems, even to imagine the possibility of an experiment that allows one to establish points of absolute space.

Absolute space gives ideas, firstly, about an arbitrarily rapidly spreading gravitational attraction, as Newton pointed out, but not about propagating with final speed electric gravitation, and, secondly, about the still not understood meaning Maxwell's equations …

* is a separate conversation; to begin with, it will be necessary to discuss the void itself.
** Any "object" in "absolutely empty space" (if it exists there) is a closed system, no (or at all) radiation, interaction with anything outside not possible - there is no "conductive medium"; what is interesting then is that any “object” in “absolutely empty space” is thus always stable and unchanged, not subject to negation and contradiction (i.e., it is not dialectical, which means it does not exist).
*** Wed.: being is indefinite immediate.
**** So available space seems unlimited, from which the sophistical statement about

Questions of space and time have always interested human society. One of the concepts of these concepts comes from the ancient atomists - Democritus, Epicurus, etc.
Hosted on ref.rf
They introduced the concept of empty space into scientific circulation and considered ᴇᴦο as homogeneous and infinite.

In the process of creating a general picture of the universe, Isaac Newton (1642-1726), of course, also could not get around the issue of the concept of space and time.

According to Newton, the world consists of matter, space and time. These three categories are independent of each other. Matter is located in infinite space. The movement of matter occurs in space and time. Newton divided space into absolute and relative. Absolute space is motionless, infinite. The relative is part of the absolute. He also classified time. By absolute, true (mathematical) time, he understood time that flows always and everywhere evenly, and relative time, according to Newton, is a measure of duration that exists in real life ˸ second, minute, hour, day, month, year. For Newton, absolute time exists and lasts uniformly on its own, regardless of any events. Absolute space and absolute time are the receptacle of all material bodies and spaces and do not depend either on these bodies, or on these processes, or on each other.

Mass Newton defines as the amount of matter and introduces the concept of ʼʼpassive forceʼʼ (force of inertia) and ʼʼactive forceʼʼ, which creates the movement of bodies.

Having studied and revealed the laws of motion, Newton thus formulated the ᴇᴦο laws˸

1st law. Any body should continue its state of rest or uniform rectilinear motion, since it is not forced by the applied forces to change this state.

2nd law. The change in motion must be proportional to the applied driving force and occur in the direction of the straight line along which this force acts.

3rd law. Action always meet equal opposition, or the impact of two bodies on each other be equal to each other and directed in opposite directions.

Nowadays, famous laws are formulated in a more convenient form˸

1. Any material body retains a state of rest or uniform rectilinear motion until the impact from other bodies causes ᴇᴦο to change this state. The desire of the body to maintain a state of rest or uniform rectilinear motion is called inertia. Therefore, the first law is also called the law of inertia.

Newtonian concept of absolute space and time. Laws of motion - concept and types. Classification and features of the category "Newton's concept of absolute space and time. Laws of motion" 2015, 2017-2018.

Gravity [From crystal spheres to wormholes] Petrov Alexander Nikolaevich

Absolute space and time

So, we have noted two key concepts: length and duration. The question arises: in relation to what to measure them? One of the answers, which seems most natural, is to recognize the existence of absolute space and time. Then both extension and duration, and absolute space and time acquire an independent physical meaning, become part of the entire physical teaching.

How did Newton define "absolute" space? He said: "Absolute space in its very essence, regardless of anything external, remains always the same and motionless."

Since the heliocentric system became universally recognized, he defined the space tied to the center of gravity as absolute solar system. Absolute space was represented as a background for the entire Universe, it was a state of absolute rest. In relation to it, in principle, it is possible to determine the absolute motion of the body - from one absolutely resting point to another.

Like absolute space, Newton postulated the existence of absolute time. He wrote in his "Principles": "Absolute private mathematical time in itself and in its essence, without any relation to anything external, flows evenly and is otherwise called duration." In other words, time moves at a constant rate from one absolute moment to the next, no matter what happens in the universe. Or - for any observer who is in any state of motion and at any point in space, time appears to be an even, continuous, identical (same) flow that determines the change of events.

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