What is the basis for determining the 24 solar terms?

The twenty-four solar terms were customized by the ancients according to the solar cycle.

Twenty-four solar terms are special festivals in the calendar to express the change of natural rhythm and establish "December architecture", which contains a long cultural connotation and historical accumulation and is an important part of the long history and culture of the Chinese nation. Four years old, three months in spring, summer, autumn and winter, two solar terms each month, each solar term has its own unique meaning.

In ancient China, agricultural production was very developed, but one disadvantage of agricultural production was that it depended on the weather to get food. People observe the sky and the sun for a long time, and naturally explore certain laws to guide people's agricultural production practice. In this way, we can grasp the change of season and the timing of sowing.

Twenty-four solar terms accurately reflect the change of natural rhythm and play an extremely important role in people's daily life. It is not only a seasonal system that guides agricultural production, but also a folk system that contains rich folk customs.

"Twenty-four solar terms" is the product of ancient farming civilization. It is a knowledge system formed by ancient ancestors following the farming season and observing the movement of celestial bodies to understand the changing laws of seasons, climate and phenology in a year. The twenty-four solar terms were originally formulated according to the changes of stars. The Big Dipper rotates once and bucket handle rotates once clockwise, which is called one of the "years" (Figure).

The current "twenty-four solar terms" are formulated according to the position of the sun on the return to the ecliptic, that is, the annual movement track of the sun is divided into 24 equal parts, each 15 is 1, and each 1 is a solar term, starting in beginning of spring and ending in severe cold.

Through historical development, the lunar calendar absorbed the solar terms of the dry calendar as a supplement to the calendar, and adjusted it to conform to the tropic year through the leap method, forming a combined calendar of yin and yang, and the "twenty-four solar terms" became an important part of the lunar calendar. In the field of international meteorology, the 24 solar terms are known as "the fifth invention of China".

2016165438+1October 30th, 24 solar terms were officially listed in UNESCO's Representative List of Intangible Cultural Heritage of Humanity.