The Ptolemaic Cosmology

The Ptolemaic Cosmology was the official scientific worldview in the area of Europe, North Africa, and the Middle East from roughly 150 AD to 1543 (when it began to be replaced). It was a geocentric model which attempted to mathematically justify older ideas put forth by Aristotle. The notion was that the Earth was in the center of the universe, and composed of the four elements which moved with imperfect motion (wind, water, fire, and earth). The heavenly bodies were composed of aether/quintessence, which was mostly transparent, completely smooth, and moved with perfect motion.

The greatest weak point of the Ptolemaic Cosmology was the aspect of “retrograde motion” which attempted to reconcile how planets appeared to be moving backwards at certain times of the year (from the perspective of the Earth) with the Aristotelian assertion that the motion of the heavenly bodies were always perfect, constant, and regular.

Galileo Galilei’s “Dialogue of the Two Chief World Systems”: https://archive.org/details/GalileiGalileoDialogueConcerningTheTwoChiefWorldSystemsEN155P.

Sources:
http://www.luminarium.org/encyclopedia/medievalcosmology.htm
“The Sphere of Sacrobosco” (downloadable): https://williammorristile.com/assets/pdfs/De_Sphaera_English.pdf
https://www.britannica.com/science/Ptolemaic-system -Retrograde Motion explained
https://www.history.com/topics/inventions/nicolaus-copernicus
http://abyss.uoregon.edu/~js/glossary/plato.html#forms
http://www.pas.rochester.edu/~blackman/ast104/aristotle8.html
https://www.britannica.com/biography/Aristarchus-of-Samos - Aristarchus of Samos (early heliocentric model)
https://web.archive.org/web/20161220230803/http://aether.lbl.gov/www/classes/p10/aristotle-physics.html -Aristotle’s elements
https://physicsinmyview.com/2020/08/model-of-aristotelian-universe.html#:~:text=In%20Aristotelian%20cosmology%2C%20everything%20was%20made%20up%20of,made%20up%20of%20fire%2C%20air%2C%20water%2C%20and%20earth.
http://abyss.uoregon.edu/~js/ast123/lectures/lec02.html -Eratosthenes, Aristarchus, Ptolomy
https://www.britannica.com/biography/Ptolemy - Claudius Ptolemy

https://origins.osu.edu/milestones/february-2016-400-years-ago-catholic-church-prohibited-copernicanism?language_content_entity=en -Galileo