Yu Xi: Difference between revisions
→Works: precession of the equinoxes, and comparison to Hipparchus |
m →Works: links |
||
| Line 10: | Line 10: | ||
p. 2010.</ref> In it he described the [[precession]] of the [[equinox]]es (i.e. [[axial precession]]).<ref name="needham ling 1995 p220">Needham and Ling (1995), p. 220.</ref> He observed that the position of the Sun during the [[winter solstice]] had drifted roughly one degree over the course of fifty years relative to the position of the stars.<ref name="sun 2017 p.120">Sun (2017), p. 120.</ref> This was the same discovery made earlier by the [[Greek astronomy|ancient Greek astronomer]] [[Hipparchus]] (c. 190-120 BC), who found that the measurements for either the Sun's path around the [[ecliptic]] to the [[vernal equinox]] or the Sun's relative position to the stars were not equal in length.<ref name="sun 2017 p.120"/> |
p. 2010.</ref> In it he described the [[precession]] of the [[equinox]]es (i.e. [[axial precession]]).<ref name="needham ling 1995 p220">Needham and Ling (1995), p. 220.</ref> He observed that the position of the Sun during the [[winter solstice]] had drifted roughly one degree over the course of fifty years relative to the position of the stars.<ref name="sun 2017 p.120">Sun (2017), p. 120.</ref> This was the same discovery made earlier by the [[Greek astronomy|ancient Greek astronomer]] [[Hipparchus]] (c. 190-120 BC), who found that the measurements for either the Sun's path around the [[ecliptic]] to the [[vernal equinox]] or the Sun's relative position to the stars were not equal in length.<ref name="sun 2017 p.120"/> |
||
Yu Xi wrote a critical analysis of the ''huntian'' (渾天) theory of the [[celestial sphere]],<ref name="knechtges chang 2014 p2010"/> arguing that [[Observable universe|the heavens]] surrounding the earth [[Static universe|were infinite]] and motionless.<ref name="needham ling 1995 p220"/> He advanced the idea that the shape of the earth was either square or round, but that it had to correspond to the shape of the heavens enveloping it.<ref name="needham ling 1995 p220"/> The ''huntian'' theory, as mentioned by [[Luoxia Hong]] (fl. 140-104 BC) and fully described by [[Zhang Heng]] (78-139 AD), insisted that the heavens were spherical and that the earth was like an egg yolk at its center.<ref>Needham and Ling (1995), pp. 216-217.</ref> Yu Xi's ideas about the infinity of [[outer space]] seem to echo Zhang's ideas of endless space even beyond the celestial sphere.<ref name="needham ling 1995 p220"/> Although mainstream Chinese science before European influence in the 17th century surmised that the Earth was [[Flat earth|flat and square-shaped]], some scholars, such as [[Li Ye (mathematician)|Li Ye]] (1192-1279 AD), proposed the idea that it was [[Spherical Earth|spherical like the heavens]].<ref>Needham and Ling (1995), pp. 498-499.</ref> The acceptance of a spherical earth can be seen in the [[Chinese astronomy|astronomical]] and [[Chinese geography|geographical]] treatise ''Gezhicao'' (格致草) written in 1648 by Xiong Mingyu (熊明遇).<ref name="needham ling 1995 p499">Needham and Ling (1995), p. 499.</ref> It rejects the square-earth theory and, with clear European influence, explains that ships are capable of [[Circumnavigation|circumnavigating]] the globe.<ref name="needham ling 1995 p499"/> However, it explained this using classical Chinese phrases, such as the earth being as round as a [[crossbow]] bullet, a phrase Zhang Heng had previously used to describe the shape of both the sun and moon.<ref>Needham and Ling (1995), pp. 227, 499.</ref> |
Yu Xi wrote a critical analysis of the ''huntian'' (渾天) theory of the [[celestial sphere]],<ref name="knechtges chang 2014 p2010"/> arguing that [[Observable universe|the heavens]] surrounding the earth [[Static universe|were infinite]] and motionless.<ref name="needham ling 1995 p220"/> He advanced the idea that the shape of the earth was either square or round, but that it had to correspond to the shape of the heavens enveloping it.<ref name="needham ling 1995 p220"/> The ''huntian'' theory, as mentioned by [[Luoxia Hong]] (fl. 140-104 BC) and fully described by the [[Han dynasty|Eastern-Han]] scholar-official [[Zhang Heng]] (78-139 AD), insisted that the heavens were spherical and that the earth was like an egg yolk at its center.<ref>Needham and Ling (1995), pp. 216-217.</ref> Yu Xi's ideas about the infinity of [[outer space]] seem to echo Zhang's ideas of endless space even beyond the celestial sphere.<ref name="needham ling 1995 p220"/> Although mainstream Chinese science before European influence in the 17th century surmised that the Earth was [[Flat earth|flat and square-shaped]], some scholars, such as [[Yuan dynasty|Yuan-era]] mathematician [[Li Ye (mathematician)|Li Ye]] (1192-1279 AD), proposed the idea that it was [[Spherical Earth|spherical like the heavens]].<ref>Needham and Ling (1995), pp. 498-499.</ref> The acceptance of a spherical earth can be seen in the [[Chinese astronomy|astronomical]] and [[Chinese geography|geographical]] treatise ''Gezhicao'' (格致草) written in 1648 by Xiong Mingyu (熊明遇).<ref name="needham ling 1995 p499">Needham and Ling (1995), p. 499.</ref> It rejects the square-earth theory and, with clear European influence, explains that ships are capable of [[Circumnavigation|circumnavigating]] the globe.<ref name="needham ling 1995 p499"/> However, it explained this using classical Chinese phrases, such as the earth being as round as a [[crossbow]] bullet, a phrase Zhang Heng had previously used to describe the shape of both the sun and moon.<ref>Needham and Ling (1995), pp. 227, 499.</ref> |
||
Yu Xi is also known to have written commentaries on the various [[Chinese classics]].<ref name="knechtges chang 2014 p2010"/> His commentaries and notes were mostly lost before the [[Tang dynasty]], but the fragments preserved in other texts were collected in a single compendium by [[Qing dynasty|Qing-dynasty]] scholar Ma Guohan (1794-1857).<ref name="knechtges chang 2014 p2010"/> |
Yu Xi is also known to have written commentaries on the various [[Chinese classics]].<ref name="knechtges chang 2014 p2010"/> His commentaries and notes were mostly lost before the [[Tang dynasty]], but the fragments preserved in other texts were collected in a single compendium by [[Qing dynasty|Qing-dynasty]] scholar Ma Guohan (1794-1857).<ref name="knechtges chang 2014 p2010"/> |
||
Revision as of 08:17, 19 February 2018
Yu Xi (虞喜; fl. 307-345 AD), courtesy name Zhongning (仲寧), was a Chinese official, scholar, and astronomer of the Jin Dynasty (265-420 AD). He is best known for his discovery of the precession of the equinoxes, independently of the earlier ancient Greek astronomer Hipparchus. He also postulated that the Earth could be spherical in shape instead of being flat and square, long before the idea became widely accepted in Chinese science thanks to European influence of the Jesuits in the 17th century.
Background and official career
The life and works of Yu Xi are described in his biography found in the Book of Jin, the official history of the Jin dynasty.[1] He was born in Yuyao, Guiji (modern Shaoxing, Zhejiang province, China). His father Yu Cha (虞察) was a military commander and his younger brother Yu Yu (虞預; fl. 307–329 AD) was likewise a scholar and writer. During the reign of Emperor Min of Jin (r. 313-317 AD) he obtained a low-level position in the administration of the governor of Guiji commandery.[2] He declined a series of nominations and promotions thereafter, including a teaching position at the imperial university in 325 AD, an appointment at the imperial court in 333 AD, and the post of cavalier attendant-in-ordinary in 335 AD.[1]
Works
In 336 AD Yu Xi wrote the An Tian Lun (安天論; Discussion of Whether the Heavens Are At Rest or Disquisition on the Conformation of the Heavens).[3] In it he described the precession of the equinoxes (i.e. axial precession).[4] He observed that the position of the Sun during the winter solstice had drifted roughly one degree over the course of fifty years relative to the position of the stars.[5] This was the same discovery made earlier by the ancient Greek astronomer Hipparchus (c. 190-120 BC), who found that the measurements for either the Sun's path around the ecliptic to the vernal equinox or the Sun's relative position to the stars were not equal in length.[5]
Yu Xi wrote a critical analysis of the huntian (渾天) theory of the celestial sphere,[1] arguing that the heavens surrounding the earth were infinite and motionless.[4] He advanced the idea that the shape of the earth was either square or round, but that it had to correspond to the shape of the heavens enveloping it.[4] The huntian theory, as mentioned by Luoxia Hong (fl. 140-104 BC) and fully described by the Eastern-Han scholar-official Zhang Heng (78-139 AD), insisted that the heavens were spherical and that the earth was like an egg yolk at its center.[6] Yu Xi's ideas about the infinity of outer space seem to echo Zhang's ideas of endless space even beyond the celestial sphere.[4] Although mainstream Chinese science before European influence in the 17th century surmised that the Earth was flat and square-shaped, some scholars, such as Yuan-era mathematician Li Ye (1192-1279 AD), proposed the idea that it was spherical like the heavens.[7] The acceptance of a spherical earth can be seen in the astronomical and geographical treatise Gezhicao (格致草) written in 1648 by Xiong Mingyu (熊明遇).[8] It rejects the square-earth theory and, with clear European influence, explains that ships are capable of circumnavigating the globe.[8] However, it explained this using classical Chinese phrases, such as the earth being as round as a crossbow bullet, a phrase Zhang Heng had previously used to describe the shape of both the sun and moon.[9]
Yu Xi is also known to have written commentaries on the various Chinese classics.[1] His commentaries and notes were mostly lost before the Tang dynasty, but the fragments preserved in other texts were collected in a single compendium by Qing-dynasty scholar Ma Guohan (1794-1857).[1]
See also
Citations
- ^ a b c d e Knechtges and Chang (2014), p. 2010.
- ^ Knechtges and Chang (2014), p. 2009.
- ^ The first English rendering is given by Needham and Ling (1995), p. 220, whereas the second translated title is provided by Knechtges and Chang (2014), p. 2010.
- ^ a b c d Needham and Ling (1995), p. 220.
- ^ a b Sun (2017), p. 120.
- ^ Needham and Ling (1995), pp. 216-217.
- ^ Needham and Ling (1995), pp. 498-499.
- ^ a b Needham and Ling (1995), p. 499.
- ^ Needham and Ling (1995), pp. 227, 499.
References
- Knechtges, David R.; Chang, Taiping. (2014). Ancient and Early Medieval Chinese Literature: a Reference Guide, vol 3. Leiden: Brill. ISBN 978-90-04-26788-6.
- Needham, Joseph; Wang, Ling. (1995) [1959]. Science and Civilization in China: Mathematics and the Sciences of the Heavens and the Earth, vol. 3, reprint edition. Cambridge: Cambridge University Press. ISBN 0-521-05801-5.
- Sun, Kwok. (2017). Our Place in the Universe: Understanding Fundamental Astronomy from Ancient Discoveries, second edition. Cham, Switzerland: Springer. ISBN 978-3-319-54171-6.