Zhang Heng was born in Nanyang County, Henan Province, located in the Central Plains. When he was young, he was thirsty for knowledge and good at writing. At the age of seventeen, he left his hometown and went to Chang 'an, which later became the capital of several dynasties in China. Zhang Heng visited the historical sites here and investigated the customs and social and economic conditions here. Later, Zhang Heng, a promising young man, was selected by the court at that time and asked several times to be an official. Zhang Heng was an official in Luoyang, the then capital, and later in Hejian.
When Zhang Heng was young, he was very interested in natural science, especially astronomy. He has both fame and fortune. He resigned from his official position twice, spent three years studying philosophy, mathematics and astronomy, accumulated a lot of knowledge and began to write books.
In the Han Dynasty more than 2,000 years ago, China's theory about the structure of the universe was very rich. At that time, there were mainly three schools of thought, namely, Gaitian theory, Huntian theory and Michelle Ye theory. Zhang Heng is a representative of Huntian Theory. He thinks the sky is like an egg and the earth is like an egg. The sky and the earth are small. They stand by air and float by water. This theory was very progressive at that time. In addition, Zhang Heng's theory of evolution of the origin of heaven and earth. Before heaven and earth were separated, there was chaos. After separation, the light rises to the sky and the heavy condenses to the ground. The sky is yang and the earth is yin. The two gases interact and create everything. Zhang Heng also explained that the speed of planetary motion varies with distance. Modern science has proved that the speed of planetary motion is related to its distance from the sun. It can be seen that Zhang Heng's explanation has reasonable factors.
Zhang Heng not only attaches importance to theoretical research, but also attaches importance to practice. He personally designed the water leakage instrument and the meteorological seismograph. Meteorological seismograph is the first instrument to test earthquakes in the world. In A.D. 138, Zhang Heng successfully recorded an earthquake in Shaanxi with it. A globe is equivalent to a globe now. Originally invented by another scientist, Zhang Heng made some improvements. He used a gear system to connect the elephants-similar to the current celestial globe and the chronometer. The leaky pot drips water to push the elephant to rotate evenly, just once a day, so that people can know when and where the stars are when they look at the elephant in the room.
Zhang Heng also observed and analyzed many specific astronomical phenomena. He counted about 2500 stars that can be seen in the Central Plains of China, and basically mastered the principle of lunar eclipse. Zhang Heng's measurement of the angular diameter of the sun and the moon is also quite accurate. Zhang Heng believes that the sun in the morning and evening is as big as the sun at noon. It looks big in the morning and evening and small at noon, which is just an optical effect. The environment in which the observer is located in the morning and evening is dark. At noon, the sky and the earth are bright, and the sun in the sky looks very small. Like fire, it is big at night and small during the day. Although Zhang Heng's explanation is not very comprehensive, it also has some truth.
Zhang Heng was not only an astronomer, but also a famous writer in the Eastern Han Dynasty. His paintings are also quite excellent, and he was listed as one of the six famous painters at that time. According to China's historical records, Zhang Heng left 32 works on science, philosophy and literature in his life, which showed Zhang Heng's attitude of being a man and doing research. This is a fantasy of human beings roaming in the starry sky and an early scientific fantasy article of China. In addition, Zhang Heng's representative works have been circulated. Xijing refers to Luoyang (now Henan Province), which narrates the local customs and customs here in a romantic and exaggerated way, and the performances of various folk skills are extremely precious historical materials for China's ancient acrobatics.