This article will pay attention to the history of the discovery of the law of gravity. Here we will familiarize ourselves with biographical information from the life of a scientist who discovered this physical dogma, consider its main provisions, its 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 strength to such sciences as physics and mathematics, and also brought a lot of new to mechanics and astronomy. It 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", which outlined information on the three laws of mechanics and the law of universal gravitation. Isaac Newton laid the foundations of classical mechanics with these works. He developed calculus of differential and integral type, light theory. He also made a great contribution to physical optics and developed many other theories in the field of physics and mathematics.
Law
The law of gravity and the history of its discovery date back to 1666. Its classical form is the law by which the interaction of the gravitational type is described, which does not go beyond the framework of mechanics.
Its essence was that the exponent of the force F of gravitational thrust arising between 2 bodies or points of matter m1 and m2, separated from each other by a certain distance r, observes proportionality to both mass indicators and is inversely proportional to the square of the distance between the bodies:
F = G, where G denotes the gravity constant equal to 6.67408 (31) • 10 -11 m 3 / kgf 2 .
Newton's gravity
Before considering the history of the discovery of the law of gravity, we will familiarize ourselves in more detail with its general characteristics.
In the theory created by Newton, all bodies with a large mass should generate around themselves a special field that attracts other objects to themselves. It is called the gravitational field, and it has potential.
A body with spherical symmetry forms a field outside of 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. Universe objects, such as, for example, a planet or a comet, also obey it, moving along an ellipse or hyperbole. Accounting for the distortion created by other massive bodies is taken into account using the provisions of perturbation theory.
Analyzing accuracy
After Newton discovered the law of gravity, it had to be verified and proved many times. For this, a series of calculations and observations were made. Having come to agreement with its provisions and based on the accuracy of its indicator, the experimental form of assessment serves as a vivid confirmation of GR. Measurement of the quadrupole interactions of the body, which rotates, but its antennas remain motionless, show us that the process of building up δ depends on the potential r - (1 + δ) , at a distance of several meters and is in the limit (2.1 ± 6.2) • 10 -3 . A number of other practical evidence has allowed this law to establish itself and take a single form, without modifications. In 2007, this dogma was rechecked at a distance of less than a centimeter (55 μm-9.59 mm). Given the errors of the experiment, scientists investigated the range of distances and did not find any obvious deviations in this law.
Observation of the orbit of the moon in relation to the Earth also confirmed its viability.
Euclidean space
Newton's classical theory of gravitation is associated with Euclidean space. Actual equality with sufficiently high accuracy (10 -9 ) of the measures of the distance measure in the denominator of equality considered above shows us the Euclidean basis of the space of Newtonian mechanics, with a three-dimensional physical form. At such a point in matter, the area of the spherical surface is precisely proportional to the size of the square of its radius.
History data
Consider a summary of the history of the discovery of the law of gravity.
Ideas were put forward by other scientists who lived in front of Newton. Reflections on her visited Epicurus, Kepler, Descartes, Roberval, Gassendi, Huygens and others. Kepler suggested that the force of gravity has the inverse proportion to the distance from the star of the Sun and that it spreads only in ecliptic planes; according to Descartes, it was a consequence of the activity of vortices in the thickness of the ether. There was a number of conjectures, which contained a reflection of the correct conjectures about the dependence on distance.
A letter from Newton to Halle contained information that the predecessors of Sir Isaac himself were Hook, Ren and Buyo Ismael. However, before him no one was able 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 deduce the law in question thanks to the Kepler's empirical law, already known by then. He shows us that:
- the form of movement of any visible planet indicates the presence of a central force;
- the central type of attractive force forms elliptical or hyperbolic orbits.
About Newton's Theory
An examination of the brief history of the discovery of the law of gravity can also point to a number of differences that set it apart from previous hypotheses. Newton was engaged not only in the publication of the proposed formula for the phenomenon under consideration, but also proposed a mathematical type model in an integral form:
- provision of the law of gravity;
- provision on the law of motion;
- taxonomy of methods of mathematical research.
This triad could sufficiently accurately investigate even the most complex movements of celestial objects, thus creating the basis for celestial mechanics. Up to the start of Einstein’s activity in this model, the existence of a fundamental set of amendments was not required. Only mathematical apparatus had to be significantly improved.
Discussion Object
The discovered and proven law throughout the eighteenth century became a well-known subject of active debate and rigorous checks. However, the century ended with general agreement with his postulates and statements. Using the calculations of the law, it was possible to accurately determine the paths of motion of bodies in heaven. A direct check was performed by Henry Cavendish in 1798. He did this using torsion-type scales with great sensitivity. In the history of the discovery of the universal law of gravity, it is necessary to allocate a special place 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 this potential. This type of model allowed us 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 was the inexplicability of long-range action. It was impossible to precisely answer the question of how the forces of attraction are transmitted through the vacuum space at infinite speed.
"Evolution" of the law
Over the next two hundred years, and even more, many physicists attempted to propose a variety of 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 closer to the beginning of work on the theory in a more general form, which can be applied under certain conditions:
- The potential of gravitational nature cannot be too large in the studied systems. The solar system is an example of compliance with all the rules for the movement of the celestial type of bodies. The relativistic phenomenon finds itself in a noticeable manifestation of perihelion displacement.
- The indicator of the speed of movement in this group of systems is insignificant in comparison with the light speed.
The proof that in a weak stationary field of gravity the calculations of general relativity take the form of Newtonian ones is the presence of a scalar potential of gravity in a stationary field with weakly expressed characteristics of forces that can satisfy the conditions of the Poisson equation.
Quantum 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 gravitational-type processes on a 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 radiation from one object to the point in time at which another point absorbed it.
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, we can conclude the provision on the law of Newton’s potential and its dependence in accordance with the inverse indicator 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 zero. The weight of photons has the same meaning.
Misconception
In the school curriculum, the answer to a question from history as Newton discovered the law of gravity is the story of the falling apple fruit. According to this legend, it fell on the head of the scientist. However, this is a widespread misconception, and in reality, everything could do without such a 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 fit of momentary insight. As it was written above, it was developed for a long time and was presented for the first time in works on the "Mathematical Principles", which were published to the public in 1687.