Heliocentric system in the works of N. Copernicus, I. Kepler, I. Newton

The question of the structure of the universe and the place in it of the planet Earth and human civilization interested scientists and philosophers from time immemorial. For a long time in the course was the so-called Ptolemy system, later called geocentric. According to her, it was the Earth that was the center of the universe, and other planets, the Moon, the Sun, the stars and other celestial bodies made their way around it. However, to the Late Middle Ages, there is already enough evidence that such an understanding of the universe is not true.

For the first time the idea that the Sun is the center of our Galaxy was expressed by the famous philosopher of the early Renaissance Nikolai Kuzansky, but his work was more of an ideological character and was not supported by any astronomical evidence.

Heliocentric system of the world as a whole scientific worldview, supported by serious evidence, began its formation in the XVI century, when a scientist from Poland N. Copernicus published his work on the motion of planets, including the Earth, around the Sun. The impetus for the creation of this theory was the long-term observations of the scientist behind the sky, as a result of which he came to the conclusion that complex movements of the planets, relying on the geocentric model, can not be explained simply. The heliocentric system explained them by the fact that as the distance from the Sun increases, the velocities of planets decrease noticeably. In this case, if the planet is behind the Earth when viewed, it seems that it is starting to move backwards.

In fact, at this moment, the given celestial body is simply at the maximum distance from the Sun, so its speed slows down. At the same time, it should be noted that the heliocentric system of the Copernican world possessed a number of significant shortcomings, borrowed from the Ptolemy system. Thus, the Polish scientist believed that, unlike other planets, the Earth moves in its orbit in a uniform manner. In addition, he argued that the center of the universe is not so much the main heavenly body as the center of the Earth's orbit, which coincides with the Sun is not completely.

All these inaccuracies were discovered and overcome by the German scientist I. Kepler. The heliocentric system seemed to him an indisputable truth, moreover, he believed that it was time to calculate the scale of our planetary system.

After long and painstaking research, in which the Danish scientist T. Brahe took an active part, Kepler concluded that, firstly, it is the Sun that represents the geometric center of that planetary system to which our Earth belongs.
Secondly, the Earth, like other planets, moves unevenly. In addition, the trajectory of its motion is not a regular circle, but an ellipse, one of the focal points of which is occupied by the Sun.

Thirdly, the heliocentric system received from Kepler a mathematical justification: in its third law the German scientist showed the dependence of the periods of revolution of planets on the extent of their orbits.

The heliocentric system created the conditions for the further development of physics. It was during this period that I. Newton, based on the work of Kepler, derived two of the most important principles of his mechanics - inertia and relativity, which became the final chord in the creation of a new system of the universe.