Zhang Heng (Chinese: 張衡; AD 78–139), formerly romanized Chang Heng, was a Chinese polymathic scientist and statesman who lived during the Han dynasty.

Zhang invented the first seismometer, a machine that measures the strength of earthquakes. He is remembered for many other inventions and writings. He invented the seismometer in 132 AD. Heng was also the first in China to apply a grid system to maps, from which positions and distances could be calculated.

In May 2018, Zheng Shuang met producer Zhang Heng when filming a reality show. The pair admitted to be dating in August 2018 and started a company together. The pair exchanged wedding vows in United States on 19 January 2019. However, they announced their breakup in December 2019.

Chinese astronomers Gan De and Shi Shen are credited as the first to create star catalogues in the 4th century BC, and the Buddhist monk Yi Xing conducted an astronomical survey in the 8th century AD to help with the prediction of solar eclipses.