Who was the first to understand that the Earth is not at the center of the universe?

In the III century BC, Aristarchus of Samos had concluded that the Earth and other planets orbit around the Sun. He also guessed about the rotation of the Earth around its own axis. However, it took a millennium and a half to defend this first heliocentric scheme of the world. That was due to the Ptolemy system described in the Almagest, in which the planets and the Sun revolve around the Earth in circular orbits and, in addition, in small circles (epicycles) centered on the main orbit. The first doubts about such a structure of the Universe arose from Leonardo da Vinci at the end of the 15th century. Half a century later, Copernicus wrote a book with the epigraph words (known from Plato) ‘Let no one unacquainted with geometry enter here’. In that book, the heliocentric system had already followed from astronomical observations collected in tables. Although Copernicus’s book was soon included in the list of heretical books, Galileo had analyzed and supported his conclusions in his publications. Half a century later, Kepler published the results of his research that the planets move in ellipses with the Sun in focus. About half a century passed when Newton discovered the law of gravity, which substantiated Kepler’s conclusions and even clarified his law on the ratio of the periods of revolution of the planets and the semi-major axes of their orbits.

On devotion to true feelings 🙂

Difference between geocentric and heliocentric world design

The concept of planetary motion along epicycles turned out to be unnecessary after Kepler’s discoveries.


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