Guo Shoujing

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Guo Shoujing (Chinese: 郭守敬; pinyin: Guō Shǒujìng; Wade-Giles: Kuo Shou-ching, 1231–1316), courtesy name Ruosi (若思), was a Chinese astronomer, engineer, and mathematician born in Xingtai, Hebei and lived during the Yuan Dynasty (1271–1368).

1 Early life
2 Contributions
3 Notes
4 References
5 External links

[edit] Early life

Guo's father died while he was a child, so he was brought up by his grandfather Guo Yong, who was famed as an expert in a wide range of topics from classical studies (Five Classics) to mathematics and hydraulics.

By the age of 15 or 16, he obtained a blueprint for a water clock, and soon realized its principles of operation.

[edit] Contributions

He worked on improving the Chinese gnomon and worked at Kublai Khan's Gaocheng Astronomical Observatory. He set 27 observation centers in different parts of China. There he formulated the Shoushili calendar (授時曆) and calculated the year to be 365.2425 days, only 26 seconds off the real time. This is the same as the Gregorian calendar, but 302 years earlier. It would be used for the next 364 years, the longest a calendar would be used in Chinese History. He also used mathematical functions in his work relating to spherical trigonometry,^[1] building upon the knowledge of Shen Kuo's (1031–1095) earlier work in trigonometry.^[2] An important work in trigonometry in China would not be printed again until the collaborative efforts of Xu Guangqi and his Italian Jesuit associate Matteo Ricci in 1607, during the late Ming Dynasty.^[2]

He devised a number of astronomical instruments, and conducted large-scale geodetic surveys and celestial observations. Although he did a great deal on the modern calendar, he suggested pi 3, unlike Zu Chongzhi's 3.14159265 and Zhang Heng's 3.142.

In engineering he is best known for constructing the artificial Kunming Lake in Beijing as a reservoir and part of a new waterway for grain transport.

Asteroid 2012 Guo Shou-Jing is named after him.

[edit] Notes

This article contains Chinese text.
Without proper rendering support, you may see question marks, boxes, or other symbols instead of Chinese characters.

^ Needham, Volume 3, 109.
^ ^a ^b Needham, Volume 3, 110.

[edit] References

Needham, Joseph (1986). Science and Civilization in China: Volume 3, Mathematics and the Sciences of the Heavens and the Earth. Taipei: Caves Books, Ltd.