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'Guo Shoujing' (, 1231–1316), courtesy name 'Ruosi' (若思), was a Chinese astronomer, engineer, and mathematician born in Xingtai, Hebei during the Yuan Dynasty.

Contents

Early life

Contributions

Notes

References

External links

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.

Contributions

He worked on improving the Chinese gnomon and worked at Kublai Khan's Gaocheng Astronomical Observatory. There he formulated the Shoushi calendar (授時曆) and calculated the year to be 365.2425 days. This is the same as the Gregorian calendar, but almost three centuries earlier. It would be used for the next 364 years. He also used mathematical functions in his work relating to spherical trigonometry.^[1]
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.

Notes

1. Needham, Volume 3, 109.

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.

External links

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★ Article on the Shoushi calendar from the National University of Singapore

★ Culture story site