The theory of the heavens

This is an ancient Chinese theory of the structure of the universe that takes the celestial sphere theory. The idea that the heavens are spherical seems to have existed since the Warring States period, but in the Western Han period, it is recorded in the Fayan (Fayan) that Lao Hang, Xianyu Mangren, and Geng Shouchang created ritual implements based on this theory, so it is certain that it already existed at that time. Zhang Heng's "Comment on the Armillary Globe" from the Later Han Dynasty is a representative book that discusses the Armillary Globe theory. It compares the universe to a chicken egg, stating that the heavens are round like a bullet, the earth is like an egg yolk and located in the center of the heavens, and that the heavens rotate on the north-south axis. It develops a discussion that is equivalent to today's spherical astronomy, which assumes a celestial sphere and deals with the apparent movement of celestial bodies, with numerical values, and describes the structure and manufacturing method of the Armillary Globe (a celestial sphere model or observation instrument that combines circles representing the ecliptic and equator of the celestial sphere). Ancient Greece also had a concept of a celestial sphere and a ritual device (almirae) equivalent to the Armillary Globe. During the Former Han and Later Han dynasties, there was a lively debate between the Armillary Globe theory and the Gaitian theory, and the Armillary Globe theory won, but there was no significant progress in the theory of the structure of the universe after that, except for a temporary revival of the Gaitian theory and attempts to harmonize the two theories.

[Kazuhiko Miyajima]

"Famous Works of Science 2: Chinese Astronomy and Mathematics" edited by Yabuuchi Kiyoshi, translated by Hashimoto Keizo and Kawahara Hideki (1980, Asahi Press)" ▽ "Reprint of "Essays on the History of Oriental Astronomy" by Noda Tadaaki (1989, Koseisha Koseisha)" ▽ "Arai Shinji, "Rethinking Zhang Heng's "Hunyi Notes" and "Hunyi Tu Notes"" (included in "Essays on the History of Science in Ancient China" edited by Yamada Keiji, 1989, Kyoto University Institute for Research in Humanities)"

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

中国の古い宇宙構造論で天球説をとる。天は球形であるとする考えは戦国時代からあったようであるが、前漢時代に落下閎(らっかこう)・鮮于妄人(せんうもうじん)・耿寿昌(こうじゅしょう)がこの説に基づく儀器をつくったことが、蓋天説(がいてんせつ)派から渾天説派に転向した揚雄(ようゆう)の『法言(ほうげん)』に記されており、このころすでに存在したことは確かである。後漢(ごかん)の張衡(ちょうこう)の『渾天儀注』は渾天説を論じた代表的な書で、宇宙を鶏卵(けいらん)に例え、天は弾丸のように丸く、大地は卵黄のように天の中心に位置し、天は南北極を軸に回転すると述べ、天球を仮定して天体の見かけの運行を扱う今日の球面天文学に相当する議論を、数値を交えて展開し、渾天儀（天球の黄道・赤道などを表す円環を組み合わせた天球模型または観測器械）の構造と製法を述べている。古代ギリシアにも天球概念や渾天儀に相当する儀器（アルミラ球儀）があった。渾天説派と蓋天説派との間では、前漢・後漢のころ、活発な議論が行われ、渾天説が勝利を収めたが、その後は一時的な蓋天説の復活や、両説の調和の試みがあっただけで、宇宙構造論の著しい進展はみられなかった。

［宮島一彦］

『藪内清編、橋本敬造・川原秀城訳『科学の名著2　中国天文学・数学集』（1980・朝日出版社）』▽『能田忠亮著『東洋天文学史論叢』覆刻版（1989・恒星社厚生閣）』▽『新井晋司著「張衡『渾儀注』『渾儀図注』再考」（山田慶児編『中国古代科学史論』所収・1989・京都大学人文科学研究所）』

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