Editing Comet (section)

=== Early observations and thought ===
From ancient sources, such as Chinese [[oracle bone]]s, it is known that comets have been noticed by humans for millennia.<ref>{{cite web |url=http://www.lib.cam.ac.uk/mulu/oracle.html |title=Chinese Oracle Bones |publisher=Cambridge University Library |access-date=14 August 2013 |archive-url=https://web.archive.org/web/20131005100532/http://www.lib.cam.ac.uk/mulu/oracle.html |archive-date=5 October 2013 |url-status=dead}}</ref> Until the sixteenth century, comets were usually considered bad [[omen]]s of deaths of kings or noble men, or coming catastrophes, or even interpreted as attacks by heavenly beings against terrestrial inhabitants.<ref>{{cite web|last=Ridpath|first=Ian|author-link=Ian Ridpath|date=8 July 2008|title=Comet lore|url=http://www.ianridpath.com/halley/halley1.htm|access-date=14 August 2013|work=A brief history of Halley's Comet}}</ref><ref>{{harvnb|Sagan|Druyan|1997|p=14}}</ref>

[[File:Mawangdui Astrology Comets Ms.JPG|thumb|upright=1.5|Detail of astrology manuscript, ink on silk, 2nd century BC, [[Han dynasty]], unearthed from [[Mawangdui]] tomb. The page gives descriptions and illustrations of seven comets, from a total of 29 found in the document (see: [[historical comet observations in China]]).<ref>Loewe, pp. 62, 64</ref>]]

[[Aristotle]] (384–322 BC) was the first known scientist to use various theories and observational facts to employ a consistent, structured cosmological theory of comets. He believed that comets were atmospheric phenomena, due to the fact that they could appear outside of the [[zodiac]] and vary in brightness over the course of a few days. Aristotle's cometary theory arose from his observations and cosmological theory that everything in the cosmos is arranged in a distinct configuration.<ref>{{cite book|last=Heidarzadeh|first=Tofigh|url=https://books.google.com/books?id=Fo-GY4J1h4cC&pg=PA1|title=A History of Physical Theories of Comets, From Aristotle to Whipple|date=2008|publisher=[[Springer Science+Business Media]]|isbn=978-1-4020-8323-5|page=1|lccn=2008924856}}</ref> Part of this configuration was a clear separation between the celestial and terrestrial, believing comets to be strictly associated with the latter. According to Aristotle, comets must be within the sphere of the moon and clearly separated from the heavens. Also in the 4th century BC, [[Apollonius of Myndus]] supported the idea that comets moved like the planets.{{Sfn|Sagan|Druyan|1997|p=48}} Aristotelian theory on comets continued to be widely accepted throughout the [[Middle Ages]], despite several discoveries from various individuals challenging aspects of it.<ref name=":0">{{cite journal|last1=Barker|first1=Peter|last2=Goldstein|first2=Bernard R.|name-list-style=amp|date=September 1988|title=The role of comets in the Copernican revolution|journal=Studies in History and Philosophy of Science Part A|volume=19|issue=3|pages=299–319|doi=10.1016/0039-3681(88)90002-7|bibcode=1988SHPSA..19..299B}}</ref>

In the 1st century AD, [[Seneca the Younger]] questioned Aristotle's logic concerning comets. Because of their regular movement and imperviousness to wind, they cannot be atmospheric,{{Sfn|Sagan|Druyan|1997|p=26}} and are more permanent than suggested by their brief flashes across the sky.{{efn|"I do not think that a comet is just a sudden fire, but that it is among the eternal works of nature." {{harv|Sagan|Druyan|1997|p=26}}}} He pointed out that only the tails are transparent and thus cloudlike, and argued that there is no reason to confine their orbits to the zodiac.{{Sfn|Sagan|Druyan|1997|p=26}} In criticizing Apollonius of Myndus, Seneca argues, "A comet cuts through the upper regions of the universe and then finally becomes visible when it reaches the lowest point of its orbit."{{Sfn|Sagan|Druyan|1997|pp=26–27}} While Seneca did not author a substantial theory of his own,<ref>{{Cite book|last=Heidarzadeh|first=Tofigh|url=https://books.google.com/books?id=Fo-GY4J1h4cC&q=a+history+of+physical+theories+on+comets&pg=PR8|title=A History of Physical Theories of Comets, From Aristotle to Whipple|date=2008-05-23|publisher=Springer Science & Business Media|isbn=978-1-4020-8323-5|language=en}}</ref> his arguments would spark much debate among Aristotle's critics in the 16th and 17th centuries.<ref name=":0" />{{efn|Seneca is quoted as stating, "Why ... are we surprised that comets, such a rare spectacle in the universe, are not yet grasped by fixed laws and that their beginning and end are not known, when their return is at vast intervals? ... The time will come when diligent research over very long periods of time will bring to light things which now lie hidden."{{sfn|Sagan|Druyan|1997|pp=37–38}}}}

In the 1st century AD, [[Pliny the Elder]] believed that comets were connected with political unrest and death.<ref>{{harvnb|Sagan|Druyan|1997|pp=27–28}}</ref> Pliny observed comets as "human like", often describing their tails with "long hair" or "long beard".<ref>{{cite book|last=Hellman|first=C. Doris|url=https://books.google.com/books?id=1_MVAwAAQBAJ&pg=PA36|title=The Comet of 1577: Its Place in the History of Astronomy|publisher=AMS Press|year=1971|isbn=0-404-51510-X|series=Columbia University Studies in the Social Sciences No. 510|page=36|lccn=72-110569|orig-year=1944}}</ref> His system for classifying comets according to their color and shape was used for centuries.<ref name=":2" />

In [[Indian astronomy|India]], by the 6th century AD astronomers believed that comets were apparitions that re-appeared periodically. This was the view expressed in the 6th century by the astronomers [[Varāhamihira]] and [[Bhadrabahu III|Bhadrabahu]], and the 10th-century astronomer [[Bhaṭṭotpala]] listed the names and estimated periods of certain comets, but it is not known how these figures were calculated or how accurate they were.<ref>{{cite book|last1=Kelley|first1=David H.|url=https://books.google.com/books?id=ILBuYcGASxcC&pg=PA293|title=Exploring Ancient Skies: A Survey of Ancient and Cultural Astronomy|last2=Milone|first2=Eugene F.|date=2011|publisher=[[Springer Science+Business Media]]|isbn=978-1-4419-7624-6|edition=2nd|page=293|doi=10.1007/978-1-4419-7624-6|bibcode=2011eas..book.....K |oclc=710113366|name-list-style=amp}}</ref><ref>{{Cite journal |last=Sharma |first=S. D. |date=1987 |title=Periodic Nature of Cometary Motions as Known to Indian Astronomers Before Eleventh Century A.D |url=https://www.cambridge.org/core/journals/international-astronomical-union-colloquium/article/periodic-nature-of-cometary-motions-as-known-to-indian-astronomers-before-eleventh-century-ad/CB4A864D932B389D94E6842EAD3F980F |journal=International Astronomical Union Colloquium |language=en |volume=91 |pages=109–112 |doi=10.1017/S0252921100105925 |issn=0252-9211}}</ref>

[[File:Bayeux Tapestry scene32 Halley comet.jpg|thumb|235px|[[Halley's Comet]] appeared in 1066, prior to the [[Battle of Hastings]], and is depicted in the [[Bayeux Tapestry]].]]

There is a claim that an Arab scholar in 1258 noted several recurrent appearances of a comet (or a type of comet), and though it's not clear if he considered it to be a single periodic comet, it might have been a comet with a period of around 63 years.<ref>{{Cite journal |last=Khalil Konsul |first=Eng. |date=2019-08-01 |title=Comet Observations in Arab Heritage Books: Did the Arabs Discover the Periodicity of Comets Before Edmund Halley? |url=https://ui.adsabs.harvard.edu/abs/2019ASPC..520...83K |journal=ASP Conference Series |volume=520 |pages=83|bibcode=2019ASPC..520...83K }}</ref>

In 1301, the Italian painter [[Giotto]] was the first person to accurately and anatomically portray a comet. In his work ''[[Adoration of the Magi]],'' Giotto's depiction of Halley's Comet in the place of the [[Star of Bethlehem]] would go unmatched in accuracy until the 19th century and be bested only with the invention of photography.<ref name=":1">{{Cite journal|last=Olson|first=Roberta J.M.|author-link=Roberta Olson|date=1984|title=... And They Saw Stars: Renaissance Representations of Comets and Pretelescopic Astronomy|journal=Art Journal|volume=44|issue=3|pages=216–224|doi=10.2307/776821|jstor=776821}}</ref>

Astrological interpretations of comets proceeded to take precedence clear into the 15th century, despite the presence of modern scientific astronomy beginning to take root. Comets continued to forewarn of disaster, as seen in the ''[[Luzerner Schilling]]'' chronicles and in the warnings of [[Pope Callixtus III]].<ref name=":1" /> In 1578, German [[Lutheran]] bishop Andreas Celichius defined comets as "the thick smoke of human sins&nbsp;... kindled by the hot and fiery anger of the [[God|Supreme Heavenly Judge]]". The next year, [[Andreas Dudith]] stated that "If comets were caused by the sins of mortals, they would never be absent from the sky."{{sfn|Sagan|Druyan|1997|pp=32–33}}