The geocentric system of the world is such a concept of the structure of the universe, according to which the central body in the entire Universe is our Earth, and the Sun, the Moon, as well as all other stars and planets revolve around it.
Earth since ancient times was considered the center of the universe, with a central axis and asymmetry "top - bottom." According to these ideas, the Earth is held in space with the help of a special support, which in early civilizations was represented by giant elephants, whales or turtles.
The geocentric system as a separate concept appeared thanks to the ancient Greek mathematician and philosopher Thales of Miletus. He represented the oceans as the support of the Earth and assumed that the Universe has a centrally symmetrical structure and has no distinguished direction. For this reason, the Earth, located in the center of the Cosmos, is at rest without any support. The student of Anaximander of Miletus, Anaximenes of Miletus, somewhat distanced himself from the conclusions of Thales of Miletus, suggesting that the Earth is held in space by compressed air.
For many centuries, the geocentric system was the only correct idea of the structure of the world. The point of view of Anaximenes of Miletus was shared by Anaxogor, Ptolemy and Parmenides. What kind of point of view was held by Democritus, history is unknown. Anaximander claimed that the shape of the Earth corresponds to a cylinder whose height is three times less than the diameter of its base. Anaxogor, Anaximenes, and Levkill claimed that the Earth was flat. The first who suggested that the Earth has the shape of a ball was the ancient Greek mathematician, mystic and philosopher - Pythagoras. Further, the Pythagoreans, Parmenides and Aristotle joined his point of view. Thus, the geocentric system was framed in a different context, its canonical form appeared.
Subsequently, the canonical form of geocentric representations was actively developed by astronomers of ancient Greece. They believed that the Earth has the shape of a ball and occupies a central position in the Universe, which also has the shape of a sphere, and also that the Cosmos rotates around the world axis, causing the movement of celestial bodies. The geocentric system was constantly improved by new discoveries.
So Anaximenes had the assumption that the higher the position of the star, the longer the period of its revolution around the Earth. The arrangement of luminaries was arranged as follows: the Moon went first from the Earth, the Sun followed it, then Mars, Jupiter and Saturn followed. Regarding Venus and Mercury, there were disagreements based on the contradiction of their location. Aristotle and Plato placed Venus and Mercury behind the Sun, and Ptolemy claimed that they were between the Moon and the Sun.
A geocentric coordinate system is used in the modern world to study the motion of the moon and spacecraft around the earth, as well as to determine the geocentric positions of celestial bodies moving around the sun . An alternative to the geocentric theory is the heliocentric system, according to which the central celestial body is the Sun, and the Earth and other planets revolve around it.