XVI-XVII centuries are rightfully called by many one of the most glorious periods in the history of physics. It was at this time that the foundations were largely laid, without which the further development of this science would be simply unthinkable. Copernicus, Galileo, Kepler have done a great job to declare physics as a science that can answer almost any question. Standing apart in a whole series of discoveries is the law of universal gravitation, the final formulation of which belongs to the outstanding English scientist Isaac Newton.
The main significance of the work of this scientist was not in his discovery of the force of universal gravitation - both Galileo and Kepler spoke about the presence of this quantity even before Newton, but in the fact that he was the first to prove that both on Earth and in space space, the same forces of interaction between bodies act.
Newton in practice confirmed and theoretically substantiated the fact that absolutely all bodies in the Universe, including thosewhich are located on the Earth, interact with each other. This interaction is called gravitational, while the process of universal gravitation itself is called gravity.
This interaction occurs between bodies because there is a special kind of matter, unlike others, which in science is called the gravitational field. This field exists and acts around absolutely any object, while there is no protection from it, since it has an unparalleled ability to penetrate any materials.
The force of universal gravitation, the definition and formulation of which was given by Isaac Newton, is directly dependent on the product of the masses of interacting bodies, and inversely on the square of the distance between these objects. According to Newton, irrefutably confirmed by practical research, the force of universal gravitation is found by the following formula:
F=Mm/r2.
The gravitational constant G, which is approximately equal to 6.6710-11(Nm2)/kg2, is of particular importance in it.
The gravitational force with which bodies are attracted to the Earth is a special case of Newton's law and is called gravity. In this case, the gravitational constant and the mass of the Earth itself can be neglected, so the formula for finding the force of gravity will look like this:
F=mg.
Here g is nothing but the acceleration of gravity, the numerical value of which is approximately equal to 9.8 m/s2.
Newton's law explains not only the processes taking place directly on the Earth, it gives an answer to many questions related to the structure of the entire solar system. In particular, the force of universal gravitation between celestial bodies has a decisive influence on the motion of the planets in their orbits. The theoretical description of this motion was given by Kepler, but its justification became possible only after Newton formulated his famous law.
Newton himself connected the phenomena of terrestrial and extraterrestrial gravitation using a simple example: when a cannon is fired, the nucleus does not fly straight, but along an arcuate trajectory. At the same time, with an increase in the charge of gunpowder and the mass of the nucleus, the latter will fly farther and farther. Finally, if we assume that it is possible to get enough gunpowder and design such a cannon that the cannonball will fly around the globe, then, having made this movement, it will not stop, but will continue its circular (ellipsoidal) movement, turning into an artificial satellite of the Earth. As a result, the force of gravity is the same in nature both on Earth and in outer space.
