Editing Gravity (section)

===Ancient world===
The nature and mechanism of gravity were explored by a wide range of ancient scholars. In [[Greece]], [[Aristotle]] believed that objects fell towards the Earth because the Earth was the center of the Universe and attracted all of the mass in the Universe towards it. He also thought that the speed of a falling object should increase with its weight, a conclusion that was later shown to be false.<ref>{{Cite web |last=Cappi |first=Alberto |title=The concept of gravity before Newton |url=http://www.cultureandcosmos.org/pdfs/16/Cappi_INSAPVII_Gravity_before_Newton.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://www.cultureandcosmos.org/pdfs/16/Cappi_INSAPVII_Gravity_before_Newton.pdf |archive-date=9 October 2022 |url-status=live |website=Culture and Cosmos}}</ref> While Aristotle's view was widely accepted throughout Ancient Greece, there were other thinkers such as [[Plutarch]] who correctly predicted that the attraction of gravity was not unique to the Earth.<ref>{{Cite journal |last1=Bakker |first1=Frederik |last2=Palmerino |first2=Carla Rita |date=1 June 2020 |title=Motion to the Center or Motion to the Whole? Plutarch's Views on Gravity and Their Influence on Galileo |url=https://www.journals.uchicago.edu/doi/abs/10.1086/709138 |journal=Isis |volume=111 |issue=2 |pages=217–238 |doi=10.1086/709138 |s2cid=219925047 |issn=0021-1753 |hdl=2066/219256 |hdl-access=free |access-date=2 May 2022 |archive-date=2 May 2022 |archive-url=https://web.archive.org/web/20220502172704/https://www.journals.uchicago.edu/doi/abs/10.1086/709138 |url-status=live }}</ref>

Although he did not understand gravity as a force, the ancient Greek philosopher [[Archimedes]] discovered the [[center of gravity]] of a triangle.<ref>{{cite book |last1=Neitz |first1=Reviel |url=https://books.google.com/books?id=ZC1MOaAkKnsC&pg=PT125 |title=The Archimedes Codex: Revealing The Secrets of the World's Greatest Palimpsest |last2=Noel |first2=William |date=13 October 2011 |publisher=Hachette UK |isbn=978-1-78022-198-4 |page=125 |access-date=10 April 2019 |archive-url=https://web.archive.org/web/20200107004958/https://books.google.com/books?id=ZC1MOaAkKnsC&pg=PT125 |archive-date=7 January 2020 |url-status=live}}</ref> He postulated that if two equal weights did not have the same center of gravity, the center of gravity of the two weights together would be in the middle of the line that joins their centers of gravity.<ref>{{cite book |author=Tuplin |first1=CJ |url=https://books.google.com/books?id=ajGkvOo0egwC&pg=PR11 |title=Science and Mathematics in Ancient Greek Culture |last2=Wolpert |first2=Lewis |publisher=Hachette UK |year=2002 |isbn=978-0-19-815248-4 |page=xi |access-date=10 April 2019 |archive-url=https://web.archive.org/web/20200117170945/https://books.google.com/books?id=ajGkvOo0egwC&pg=PR11 |archive-date=17 January 2020 |url-status=live}}</ref> Two centuries later, the Roman engineer and architect [[Vitruvius]] contended in his ''[[De architectura]]'' that gravity is not dependent on a substance's weight but rather on its "nature".<ref>{{Cite book  | last = Vitruvius  | first = Marcus Pollio  | author-link = Marcus Vitruvius Pollio  | editor = Alfred A. Howard  | title = De Architectura libri decem  | trans-title = Ten Books on Architecture  | place = Harvard University, Cambridge  | publisher = Harvard University Press  | date = 1914  | chapter = 7  | page = 215  | chapter-url = http://www.gutenberg.org/files/20239/20239-h/29239-h.htm#Page_215  | others = Herbert Langford Warren, Nelson Robinson (illus), Morris Hicky Morgan  | access-date = 10 April 2019 | archive-date = 13 October 2016 | archive-url = https://web.archive.org/web/20161013193438/http://www.gutenberg.org/files/20239/20239-h/29239-h.htm#Page_215  | url-status = live  }}</ref> In the 6th century CE, the [[Byzantine Empire|Byzantine]] Alexandrian scholar [[John Philoponus]] proposed the theory of impetus, which modifies Aristotle's theory that "continuation of motion depends on continued action of a force" by incorporating a causative force that diminishes over time.<ref>Philoponus' term for impetus is "ἑνέργεια ἀσώματος κινητική" ("incorporeal motive ''[[Potentiality and actuality|enérgeia]]''"); see ''[[Commentaria in Aristotelem Graeca|CAG]]'' XVII, [https://books.google.com/books?id=dVcqvVDiNVUC ''Ioannis Philoponi in Aristotelis Physicorum Libros Quinque Posteriores Commentaria''] {{Webarchive|url=https://web.archive.org/web/20231222224140/https://books.google.com/books?id=dVcqvVDiNVUC |date=22 December 2023 }}, [[Walter de Gruyter]], 1888, p. 642: "λέγω δὴ ὅτι ἑνέργειά τις ἀσώματος κινητικὴ ἑνδίδοται ὑπὸ τοῦ ῥιπτοῦντος τῷ ῥιπτουμένῳ [I say that impetus (incorporeal motive energy) is transferred from the thrower to the thrown]."</ref>

In 628 CE, the [[India]]n mathematician and astronomer [[Brahmagupta]] proposed the idea that gravity is an attractive force that draws objects to the Earth and used the term ''[[wikt:गुरुत्वाकर्षण|gurutvākarṣaṇ]]'' to describe it.<ref>{{cite book |last1=Pickover |first1=Clifford |url=https://books.google.com/books?id=SQXcpvjcJBUC&pg=PA105 |title=Archimedes to Hawking: Laws of Science and the Great Minds Behind Them |date=16 April 2008 |publisher=Oxford University Press |isbn=9780199792689 |language=en |access-date=29 August 2017 |archive-url=https://web.archive.org/web/20170118060420/https://books.google.com/books?id=SQXcpvjcJBUC |archive-date=18 January 2017 |url-status=live}}</ref>{{rp|105}}<ref>{{cite book |last1=Bose |first1=Mainak Kumar |url=https://books.google.com/books?id=nbItAAAAMAAJ&q=gravity |title=Late classical India |publisher=A. Mukherjee & Co. |year=1988 |language=en |access-date=28 July 2021 |archive-url=https://web.archive.org/web/20210813203602/https://books.google.com/books?id=nbItAAAAMAAJ&q=gravity |archive-date=13 August 2021 |url-status=live}}</ref><ref>{{cite book |last=Sen |first=Amartya |title=The Argumentative Indian |date=2005 |publisher=Allen Lane |isbn=978-0-7139-9687-6 |page=29}}</ref>

In the ancient [[Middle East]], gravity was a topic of fierce debate. The [[Persians|Persian]] intellectual [[Al-Biruni]] believed that the force of gravity was not unique to the Earth, and he correctly assumed that other [[Astronomical object|heavenly bodies]] should exert a gravitational attraction as well.<ref>{{cite book |last1=Starr |first1=S. Frederick |title=Lost Enlightenment: Central Asia's Golden Age from the Arab Conquest to Tamerlane |date=2015 |publisher=Princeton University Press |isbn=9780691165851 |page=260 |url=https://books.google.com/books?id=hWyYDwAAQBAJ&pg=PA260}}</ref> In contrast, [[Al-Khazini]] held the same position as Aristotle that all matter in the [[Universe]] is attracted to the center of the Earth.<ref>{{Cite encyclopedia|encyclopedia=Encyclopedia of the History of Arabic Science|editor-first=Rāshid|editor-last=Rushdī|date=1996|publisher=Psychology Press|isbn=9780415124119|first1=Mariam |last1=Rozhanskaya |first2=I. S. |last2=Levinova |title=Statics |volume=2 |pages=614–642}}</ref>

[[File:The Leaning Tower of Pisa SB.jpeg|thumb|upright|The [[Leaning Tower of Pisa]], where according to legend Galileo performed an experiment about the speed of falling objects]]