Discover Ptolemy's theory in a SUMMARY way

Throughout history many thinkers have tried to place the Earth and the rest of the planets and stars that surround us in a space, achieving some of them discover the truth, while others were only able to create wrong models, but they were maintained over time for centuries. To talk about one of these theories, in this lesson from a TEACHER we are going to talk about the Ptolemy theory summarized.

To begin this lesson we must talk about the figure of Claudius Ptolemy, to the context of his life to understand the reasons why he studied the position of the Earth regarding other planets and stars, and the reasons why he was such an important figure.

Ptolemy was a astronomer and geographer he was born in the year 100 in Ptolemaida, a city of Upper Egypt, and died in the year 170 in the Egyptian city of Canopo, although other sources place the death of him in the city of Alexandria, being difficult to find out due to the few sources that speak about him theme.

Throughout his life he lived and worked in Egypt, and it is said that he was one of the great thinkers who worked in

the Library of Alexandria, rivaling historical geniuses like Hipparchus of Nicea. It was thanks to his work in the library that he accomplished enormous feats in such important fields as astronomy or geography, some of which are as follows:

• He built an enormous amount of sundials.
• He created the first horoscopes of Roman and Egyptian society, although it is believed that more primitive versions had already existed in societies such as the Sumerian or china.
• He created a series of world maps with great accuracy of the Mediterranean part, since he relied on Roman military maps to draw these areas, thus being helped by the enormous Roman expansion. On the other hand, the most remote areas such as the Asian countries that negotiated with Rome, and that had never fought with them, they were invented, since Ptolemy had no way of demonstrating their form and surface.
• He collected much of the scientific knowledge in large volumes, summarizing all that was known about Greek astronomy, which served scientists throughout Europe for years.
• He was an empiricist, looking for the already existing information on the topics to create great models based on the comparison between all these texts.
• He conducted numerous studies on the properties than light he had about optics.

• He did a series of studies relating mathematics, music, and the motion of the planets.

  His studies on trigonometry They were so important that for centuries they were the basis of many studies.

Ptolemy's theory is also known as geocentric theory, but before talking about Ptolemy's theory we must comment on some of the previous models, which greatly influenced an empiricist as he was Ptolemy. Some of the early geocentric models are as follows.

Presocratic theory

The geocentric model began to be used from the beginning of the pre-Socratic Greek philosophy, that is, the period from the appearance of Thales of Miletus to the arrival of the philosophy of Socrates. From this time we can draw two important versions of the geocentric model, that of Anaximander that speaks of a cylinder-shaped Earth with the rest of the celestial bodies floating around it, and another version of the Pythagoreans that speaks about an Earth that was not the center of the universe, and that revolved around a kind of fire that was impossible to see.

Plato's theory

Plato thought that Earth was a sphere that was at the center of the entire universe, the rest of planets and stars revolved around our planet, being located in different circles celestial, being in order the following: Moon, Sun, Venus, Mercury, Mars, Jupiter, Saturn and the stars immobile.

Aristotle theory

Aristotle was Plato's apprentice, and one of the greatest thinkers in history, and like every great Greek philosopher he also had a theory on this type of model. According to Aristotle, the Earth was a sphere at the center of the universe, and the rest of the celestial bodies were linked together by a series of transparent spheres. His theory was closely linked to the 4 classical elements and the ether, this being the element from which the celestial bodies were made.

To conclude this lesson on Ptolemaic theory, we must talk about Ptolemy's geocentric theory, also known as the Ptolemaic model.

One of the main problems with the theories we mentioned above is that they did not give reasons for which the different celestial bodies could be seen more or less clearly depending on the distance at which they were they found. That is why Ptolemy based on the theories of previous thinkers created a new model, something more certain. The importance of this model was such that for a thousand years it was accepted as the cosmological model more correct, both for European and Muslim sky scholars.

According to Ptolemy's theory, the Earth was the center of the universe, and the rest of the celestial bodies revolved around it. The planets revolved around a kind of spheres, which in turn revolve around us. planet, causing all celestial bodies to make a series of perfect turns around the planet. Land. Therefore we can say that each celestial body revolved around a small circle called epicycle, and this in turn revolved on another larger circle called deferent, which was centered on the Land.

The great importance of this theory is due to the fact that it remained the main one for more than a thousand years, until the new copernican system proved to be much more real than that of Ptolemy.