Editing Planet (section)

==== Greco-Roman astronomy ====
{{See also|Ancient Greek astronomy}}

The [[Ancient Greece|ancient Greeks]] initially did not attach as much significance to the planets as the Babylonians. In the 6th and 5th centuries BC, the [[Pythagoreans]] appear to have developed [[Pythagorean astronomical system|their own independent planetary theory]], which consisted of the Earth, Sun, Moon, and planets revolving around a "Central Fire" at the center of the Universe. [[Pythagoras]] or [[Parmenides]] is said to have been the first to identify the evening star ([[Hesperos]]) and morning star ([[Phosphoros]]) as one and the same ([[Aphrodite]], Greek corresponding to Latin [[Venus]]),<ref name="burnet">{{cite book | first=John |last=Burnet |title= Greek philosophy: Thales to Plato |date=1950 |publisher=Macmillan and Co. |pages=7–11 |url=https://books.google.com/books?id=7yUAmmqHHEgC&pg=PR4 |access-date=7 February 2008 |isbn=978-1-4067-6601-1}}</ref> though this had long been known in Mesopotamia.<ref name=Cooley>{{cite journal |last=Cooley |first=Jeffrey L. |title=Inana and Šukaletuda: A Sumerian Astral Myth |url=https://www.academia.edu/1247599 |journal=KASKAL |volume=5 |pages=161–172 |year=2008 |issn=1971-8608 |quote=The Greeks, for example, originally identified the morning and evening stars with two separate deities, Phosphoros and Hesporos respectively. In Mesopotamia, it seems that this was recognized prehistorically. Assuming its authenticity, a cylinder seal from the Erlenmeyer collection attests to this knowledge in southern Iraq as early as the Late Uruk / Jemdet Nasr Period, as do the archaic texts of the period. [...] Whether or not one accepts the seal as authentic, the fact that there is no epithetical distinction between the morning and evening appearances of Venus in any later Mesopotamian literature attests to a very, very early recognition of the phenomenon. |access-date=26 November 2022 |archive-date=24 December 2019 |archive-url=https://web.archive.org/web/20191224105634/https://www.academia.edu/1247599 |url-status=live }}</ref><ref>{{Cite journal |last=Kurtik |first=G. E. |date=June 1999 |title=The identification of Inanna with the planet Venus: A criterion for the time determination of the recognition of constellations in ancient Mesopotamia |url=http://www.tandfonline.com/doi/abs/10.1080/10556799908244112 |journal=Astronomical & Astrophysical Transactions |language=en |volume=17 |issue=6 |pages=501–513 |doi=10.1080/10556799908244112 |bibcode=1999A&AT...17..501K |issn=1055-6796 |access-date=13 July 2022 |archive-date=16 June 2022 |archive-url=https://web.archive.org/web/20220616151834/https://www.tandfonline.com/doi/abs/10.1080/10556799908244112 |url-status=live }}</ref> In the 3rd century BC, [[Aristarchus of Samos]] proposed a [[Heliocentrism|heliocentric]] system, according to which Earth and the planets revolved around the Sun. The geocentric system remained dominant until the [[Scientific Revolution]].<ref name="TMU"/>

By the 1st century BC, during the [[Hellenistic period]], the Greeks had begun to develop their own mathematical schemes for predicting the positions of the planets. These schemes, which were based on geometry rather than the arithmetic of the Babylonians, would eventually eclipse the Babylonians' theories in complexity and comprehensiveness and account for most of the astronomical movements observed from Earth with the naked eye. These theories would reach their fullest expression in the ''[[Almagest]]'' written by [[Ptolemy]] in the 2nd century CE. So complete was the domination of Ptolemy's model that it superseded all previous works on astronomy and remained the definitive astronomical text in the Western world for 13 centuries.<ref name="practice" /><ref name="almagest" /> To the Greeks and Romans, there were seven known planets, each presumed to be [[Geocentric model|circling Earth]] according to the complex laws laid out by Ptolemy. They were, in increasing order from Earth (in Ptolemy's order and using modern names): the Moon, Mercury, Venus, the Sun, Mars, Jupiter, and Saturn.<ref name="oed">{{cite encyclopedia | url= http://dictionary.oed.com/cgi/entry/50180718?query_type=word&queryword=planet | dictionary= Oxford English Dictionary | title= planet, n | access-date= 7 February 2008 | date= 2007 | archive-date= 3 July 2012 | archive-url= https://web.archive.org/web/20120703072456/http://oed.com/public/redirect/welcome-to-the-new-oed-online | url-status= live }} ''Note: select the Etymology tab ''</ref><ref name="almagest">{{cite journal |first=Bernard R. |last=Goldstein |title=Saving the phenomena: the background to Ptolemy's planetary theory | journal=Journal for the History of Astronomy |volume=28 |issue=1 |date=1997 |pages=1–12 |bibcode=1997JHA....28....1G|doi=10.1177/002182869702800101 |s2cid=118875902 }}</ref><ref>{{cite book |title=Ptolemy's Almagest |author1= Ptolemy |author-link=Ptolemy |author2=Toomer, G. J. |author2-link=G. J. Toomer |publisher=Princeton University Press |date=1998 |isbn=978-0-691-00260-6}}</ref>