Zhang Heng

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Zhang Heng (Chinese postage stamp, 1955)
Detailed replica of the seismograph by Zhang Heng ( Houfeng Didong Yi )

Zhang Heng ( Chinese  張衡  /  张衡 , Pinyin Zhāng Héng , W.-G. Chang Heng ; * 78 in Nanyang , † 139 in Luoyang ) was a Chinese mathematician , astronomer , geographer , writer and inventor of the Han period.

Life

At the age of 16, Zhang Heng left his family to study in various Chinese cities. After initially studying literature and authoring various respectable literary works, he turned to astronomy when he was around 30 . He soon gained a reputation as a scientist and as such entered the government at the age of 38. He quickly made a career and eventually became a minister and chief astronomer of the Han Dynasty under Emperor Liu Hu (Anti) .

plant

As chief astronomer, Zhang Heng introduced a reform of the calendar system in 123 with the aim of bringing the months back into line with the seasons.

Zhang's cosmological view of the world was based on the idea that the earth and sky are spherical, with the earth in the center.

Zhang Heng was the inventor of what is probably the world's first seismograph - or more precisely: the first seismoscope . An inverted pendulum was set in motion by the earthquake waves, which in turn triggered a ball over one of the dragon's heads. It fell into the corresponding toad's mouth and generated a signal. The respective dragon head indicated the direction of the quake epicenter . 138 reported it after an earthquake 640 km away in Longxi .

He also developed the first armillary sphere , which rotates around its own axis with the help of water power. His model represents an imaginary celestial sphere that surrounds the earth. The earth is divided into interlocking rings, which stand for imagined lines, under which there is also a celestial equator and a celestial meridian. Scales are applied to all rings with which astronomers can locate stars .

In 1970 the lunar crater Chang Heng was named after him, and around 1978 the asteroid (1802) Zhang Heng .

Zhang Heng's grave has been on the list of monuments of the People's Republic of China since 1988 .

Web links

Individual evidence

  1. ^ A b Jacqueline Fortey: Great Scientists. [the book with poster!] Dorling Kindersley, Munich 2011, ISBN 978-3-8310-1884-0 .
  2. ↑ Chang Heng in the Gazetteer of Planetary Nomenclature of the IAU (WGPSN) / USGS
  3. ↑ Minor Planet Circ. 4419


Note: This article places the family name before the person's first name. This is the usual order in Chinese. Zhang is the family name here, Heng is the first name.
personal data
SURNAME Zhang, Heng
ALTERNATIVE NAMES Chang, Heng; Zhang, Pingzi; Chang, P'ing-tzu
BRIEF DESCRIPTION Chinese astronomer and scientist (ancient)
DATE OF BIRTH 78
PLACE OF BIRTH Nanyang
DATE OF DEATH 139
Place of death Luoyang