Zhang Heng (張衡, Pinyin: Zhāng Héng, EFEO: Tchang Heng, Lagging-Gilles: Chang Heng) (78 - 139) is a Astronome, Mathématicien, inventive, Artiste and a scholar of Littérature under the Dynastie Han in China.

Biography

Born with Nanyang in the current province from the Henan, he is a good writer as of the twelve years age. At sixteen years, it leaves its house to continue its studies with the capital. It spends at least ten years of its youth in literary studies and writing. It publishes several recognized literary writings of which two were on Luoyang and Chang' year joined together under the name of Were on the two capitals 二京賦.

It rocks in astronomy after thirty years. It becomes official government at thirty-eight years. When he is Minister for the government, he fights against corruption in the local government.

Works

In the year 123, it corrects the Calendrier to align it with the seasons.

In 132, Zhang invents the first Sismographe for measurement of the earthquakes. It emits the theory according to which the universe is like an egg with stars on the shell and the Earth like the yellow. Zhang Heng is the first nobody in China to build a celestial Globe rotary. He invents also the Odomètre.

In one of its publications líng xiàn (《靈憲》 a summary of the astronomical theories of time), it makes an approximation of pi by fraction 730/232 (or in decimal form 3,1466). In one of its formulas for the calculation of spherical volume, it uses also π like square Racine of 10 (or in decimal form 3,162).

See too

• Zhang Heng, the lunar crater named in its honor

• Sciences in Chinese antiquity

Zh-classical: 張衡