How did the 24 solar terms in China come from?

Solar terms refer to 24 specific festivals in the solar calendar (solar calendar) that indicate seasonal changes. They are formulated according to the position change of the earth on the ecliptic (that is, the orbit of the earth around the sun), and each one corresponds to a certain position reached by the earth every time it moves 15 on the ecliptic. Twenty-four solar terms are a knowledge system formed in ancient times by observing the movement of the sun for a year and understanding the changing laws of the four seasons, climate and phenology in a year.

It divides the sun's annual trajectory into 24 equal parts, and each equal part is a solar term, starting from beginning of spring and ending with the great cold. Each solar term represents different changes in climate, phenology and time. China's lunar calendar is a combination of yin and yang, which is based on the movement of the sun and the moon, so adding 24 solar terms can better reflect the cycle of the sun's movement.