How did the "twenty-four solar terms" of a year come into being?

Twenty-four solar terms, a supplementary calendar specially used to guide farming in ancient China, originated in the Spring and Autumn Period and the Warring States Period, and was formulated according to the orbit of the sun, which was the crystallization of the wisdom of the ancient working people in China.

The twenty-four solar terms are:

Beginning of spring, Rain, Creeping, Vernal Equinox, Qingming, Grain Rain, Changxia, Xiaoman, Mangzhong, Summer Solstice, Xiaoshu, Dashu, beginning of autumn, Chushu, Bailu, Autumnal Equinox, Cold Dew, Chufrost, beginning of winter, Light Snow, Heavy Snow, Winter Solstice, Slight Cold and Severe Cold.

In ancient China, people used earth gauges to measure the sundial, and the longest day of the annual sun shadow was defined as? Solstice? Also known as the winter solstice, which day has the shortest sun shadow? How short is a day? Also known as the summer solstice. What are the days when day and night are equal in spring and autumn? Equinox? And then what? Autumn equinox? .

In Shang dynasty, people only formulated four solar terms, but in Zhou dynasty, it increased to eight. It was not until the Qin and Han Dynasties that the twenty-four solar terms were fully established.

In BC 104, taichu calendar, written by Deng Ping and others, formally defined 24 solar terms and determined their astronomical positions.

The names of the twenty-four solar terms first appeared in Huainan Xun, and were compiled into calendars during the reign of Emperor Wu of the Han Dynasty. The month without neutral atmosphere was designated as the last month of leap month.

Each of the 24 solar terms corresponds to 15 for every movement of the sun on the ecliptic. The positions of the 24 solar terms are divided into 12 solar terms and 12 solar terms, which correspond to each other one by one. The twenty-four solar terms reflect the annual apparent motion of the sun, so their dates are relatively fixed in the Gregorian calendar.

For example, the "vernal equinox" is the moment when the sun passes the vernal equinox, followed by Tomb-Sweeping Day and Grain Rain. Because the time it takes for the sun to travel to 15 degrees on the ecliptic is slightly different, some are 14.7 days and some are 15.7 days between adjacent solar terms.

In China on October 30th, 2065438+06165438+/kloc-0? 24 solar terms? It was officially listed in the representative list of human intangible cultural heritage by UNESCO.