This article will focus on the history of the discovery of the law of universal gravitation. Here we will get acquainted with the biographical information from the life of the scientist who discovered this physical dogma, consider its main provisions, the relationship with quantum gravity, the course of development, and much more.
Genius
Sir Isaac Newton is a scientist from England. At one time, he devoted much attention and effort to such sciences as physics and mathematics, and also brought a lot of new things to mechanics and astronomy. He is rightfully considered one of the first founders of physics in its classical model. He is the author of the fundamental work "Mathematical Principles of Natural Philosophy", where he presented information about the three laws of mechanics and the law of universal gravitation. Isaac Newton laid the foundations of classical mechanics with these works. He developed the calculus of differential and integral type, light theory. He also made major contributions to physical optics.and developed many other theories in physics and mathematics.
Law
The law of universal gravitation and the history of its discovery date back to 1666. Its classical form is a law that describes the interaction of the gravitational type, which does not go beyond the framework of mechanics.
Its essence was that the indicator of the force F of the gravitational pull arising between 2 bodies or points of matter m1 and m2, separated from each other by a certain distance r, is proportional to both mass indicators and has an inverse proportionality to the square distances between bodies:
F=G, where G denotes the gravitational constant equal to 6, 67408(31)•10-11 m3 /kgf2.
Newton's gravity
Before considering the history of the discovery of the law of universal gravitation, let's take a closer look at its general characteristics.
In the theory created by Newton, all bodies with a large mass must generate a special field around them, which attracts other objects to itself. It's called a gravitational field, and it has potential.
A body with spherical symmetry forms a field outside itself, similar to that created by a material point of the same mass located in the center of the body.
The direction of the trajectory of such a point in the gravitational field, created by a body with a much larger mass, obeys Kepler's law. Objects of the universe, such as, for example,planet or comet, also obey him, moving in an ellipse or hyperbola. Accounting for the distortion that other massive bodies create is taken into account using the provisions of the perturbation theory.
Analyzing accuracy
After Newton discovered the law of universal gravitation, it had to be tested and proved many times over. For this, a number of calculations and observations were made. Having come to agreement with its provisions and proceeding from the accuracy of its indicator, the experimental form of estimation serves as a clear confirmation of GR. Measurement of quadrupole interactions of a body that rotates, but its antennas remain stationary, show us that the process of increasing δ depends on the potential r -(1+δ), at a distance of several meters and is located in limit (2, 1±6, 2)•10-3. A number of other practical confirmations allowed this law to be established and take a single form, without any modifications. In 2007, this dogma was rechecked at a distance less than a centimeter (55 microns-9.59 mm). Taking into account the experimental errors, the scientists examined the distance range and found no obvious deviations in this law.
Observation of the Moon's orbit in relation to the Earth also confirmed its validity.
Euclidean space
Newton's classical theory of gravity is linked to Euclidean space. The actual equality with a sufficiently high accuracy (10-9) of the distance measures in the denominator of the equality discussed above shows us the Euclidean basis of the space of Newtonian mechanics, with a three-dimensional physical form. ATto such a point of matter, the area of a spherical surface is exactly proportional to the value of the square of its radius.
Data from history
Let's consider a brief summary of the history of the discovery of the law of universal gravitation.
Ideas were put forward by other scientists who lived before Newton. Epicurus, Kepler, Descartes, Roberval, Gassendi, Huygens and others visited reflections on it. Kepler put forward the assumption that the gravitational force is inversely proportional to the distance from the star of the Sun and has distribution only in the ecliptic planes; according to Descartes, it was a consequence of the activity of vortices in the thickness of the ether. There was a series of guesses that contained a reflection of the correct guesses about the dependence on distance.
A letter from Newton to Halley contained information that the predecessors of Sir Isaac himself were Hooke, Wren and Buyo Ismael. However, no one before him managed to clearly, using mathematical methods, connect the law of gravity and planetary motion.
The history of the discovery of the law of universal gravitation is closely connected with the work "Mathematical Principles of Natural Philosophy" (1687). In this work, Newton was able to derive the law in question thanks to Kepler's empirical law, which was already known by that time. He shows us that:
- the form of movement of any visible planet indicates the presence of a central force;
- The force of attraction of the central type forms elliptical or hyperbolic orbits.
About Newton's theory
Reviewing the brief history of the discovery of the law of universal gravitation can also point us to a number of differences that set it apart from previous hypotheses. Newton was engaged not only in the publication of the proposed formula of the phenomenon under consideration, but also proposed a model of a mathematical type in a holistic form:
- provision on the law of gravity;
- statute on the law of motion;
- systematics of methods of mathematical research.
This triad was able to quite accurately investigate even the most complex movements of celestial objects, thus creating the basis for celestial mechanics. Up to the beginning of Einstein's activity in this model, the presence of a fundamental set of corrections was not required. Only the mathematical apparatus had to be significantly improved.
Object for discussion
Discovered and proven law throughout the eighteenth century became a well-known subject of active disputes and scrupulous checks. However, the century ended with a general agreement with his postulates and statements. Using the calculations of the law, it was possible to accurately determine the paths of the movement of bodies in heaven. A direct check was made by Henry Cavendish in 1798. He did this using a torsion-type balance with great sensitivity. In the history of the discovery of the universal law of gravitation, a special place must be given to the interpretations introduced by Poisson. He developed the concept of the potential of gravity and the Poisson equation, with which it was possible to calculate thispotential. This type of model made it possible to study the gravitational field in the presence of an arbitrary distribution of matter.
There were many difficulties in Newton's theory. The main one could be considered the inexplicability of long-range action. It was impossible to accurately answer the question of how the forces of attraction are sent through vacuum space at an infinite speed.
"Evolution" of the law
The next two hundred years, and even more, attempts were made by many physicists to propose various ways to improve Newton's theory. These efforts ended in a triumph in 1915, namely the creation of the General Theory of Relativity, which was created by Einstein. He was able to overcome the whole set of difficulties. In accordance with the correspondence principle, Newton's theory turned out to be an approximation to the beginning of work on a theory in a more general form, which can be applied under certain conditions:
- The potential of gravitational nature cannot be too large in the systems under study. The solar system is an example of compliance with all the rules for the movement of celestial bodies. The relativistic phenomenon finds itself in a noticeable manifestation of perihelion shift.
- The rate of movement in this group of systems is negligible compared to the speed of light.
Proof that in a weak stationary gravitational field, GR calculations take the form of Newtonian ones is the presence of a scalar potential of gravitation in a stationary field withweakly expressed characteristics of forces, which is able to satisfy the conditions of the Poisson equation.
Quanta Scale
However, in history, neither the scientific discovery of the law of universal gravitation, nor the General Theory of Relativity could serve as the final gravitational theory, since both do not adequately describe the processes of the gravitational type on the quantum scale. An attempt to create a quantum gravitational theory is one of the most important tasks of modern physics.
From the point of view of quantum gravity, the interaction between objects is created by the interchange of virtual gravitons. In accordance with the uncertainty principle, the energy potential of virtual gravitons is inversely proportional to the time interval in which it existed, from the point of emission by one object to the point in time at which it was absorbed by another point.
In view of this, it turns out that on a small scale of distances, the interaction of bodies entails the exchange of virtual type gravitons. Thanks to these considerations, it is possible to conclude the provision on the law of Newton's potential and its dependence in accordance with the reciprocal of proportionality with respect to distance. The presence of an analogy between the laws of Coulomb and Newton is explained by the fact that the weight of gravitons is equal to zero. The weight of photons has the same meaning.
Deception
In the school curriculum, the answer to a question from history, howNewton discovered the law of universal gravitation, is the story of a falling apple fruit. According to this legend, it fell on the head of a scientist. However, this is a widespread misconception, and in fact, everything was able to do without a similar case of a possible head injury. Newton himself sometimes confirmed this myth, but in reality the law was not a spontaneous discovery and did not come in a burst of momentary insight. As it was written above, it was developed for a long time and was presented for the first time in the works on the "Principles of Mathematics", which appeared on public display in 1687.
