Editing Cosmos (section)

=== Early beliefs ===
Prior to the Copernican Revolution, the Ptolemaic system, also known as the geocentric model, was widely accepted. This put the Earth at the center of the universe, with the Sun and other planets revolving around the Earth in an epicyclic orbit.<ref>{{Cite web|title=Ptolemaic System {{!}} Encyclopedia.com|url=https://www.encyclopedia.com/science-and-technology/astronomy-and-space-exploration/astronomy-general/ptolemaic-system|access-date=2020-08-31|website=www.encyclopedia.com|archive-date=2020-07-28|archive-url=https://web.archive.org/web/20200728210218/https://www.encyclopedia.com/science-and-technology/astronomy-and-space-exploration/astronomy-general/ptolemaic-system|url-status=live}}</ref> Aristotle's geocentric model was also broadly acknowledged, along with his claim that the planets rotated but did not orbit. The reasoning behind this was due to the belief that all objects outside of the lunar sphere were celestial bodies, and therefore could not change, as they were made of ''quintessence.''<ref>{{Cite book|last=Bala|first=Arun|date=2006|title=The Dialogue of Civilizations in the Birth of Modern Science|doi=10.1057/9780230601215|isbn=978-0230609792|s2cid=142593876 }}</ref>

There were notable critiques of this model prior to Copernicus. In the Islamic world, [[Ibn al-Haytham]] doubted Ptolemy's notion of the planetary orbits, and [[Al-Battani|Muhammad al-Battani]] recalculated the parameters. However, both still agreed with the geocentric model.<ref>{{Cite journal|title=2008Obs...128..231G Page 231|bibcode=2008Obs...128..231G|last1=Guessoum |first1=N. |journal=The Observatory |year=2008 |volume=128 |page=231 }}</ref>

One of the first known astronomers that supported the Heliocentric theory was [[Aristarchus of Samos]]. After observing a [[lunar eclipse]], he came to the conclusion that the Sun was farther away from Earth than the Moon and that the Sun was much larger than Earth. He also claimed the Sun was a star. While Aristarchus was later an influence on Copernicus and his groundbreaking work, prior to the 17th century Aristarchus' findings were obstructed by the more established theories of Ptolemy and Aristotle.<ref>{{Cite web|title=Ask a Solar Physicist|url=http://solar-center.stanford.edu/FAQ/Qsunasstar.html|access-date=2020-08-31|website=solar-center.stanford.edu|archive-date=2017-07-10|archive-url=https://web.archive.org/web/20170710011853/http://solar-center.stanford.edu/FAQ/Qsunasstar.html|url-status=live}}</ref><ref>{{Cite web|title=Aristarchus of Samos {{!}} Greek astronomer|url=https://www.britannica.com/biography/Aristarchus-of-Samos|access-date=2020-08-31|website=Encyclopedia Britannica|language=en|archive-date=2020-08-12|archive-url=https://web.archive.org/web/20200812075650/https://www.britannica.com/biography/Aristarchus-of-Samos|url-status=live}}</ref>