The relationship between the origin of the twenty-four solar terms and the astronomical calendar

The origin of the twenty-four solar terms The accurate determination of the winter solstice is the basis of the twenty-four solar terms. It seems that if we divide the time between two winter solstices by 24, we can get 24 solar terms. In fact, it took our ancestors a long time to understand the solar terms. China is one of the earliest countries with developed agriculture. Our ancestors attached great importance to the role of weather in long-term agricultural production. "Everything is wrong" said: "Time waits for no one, although ten days can't give birth to an ear in winter." Jia Sixie of the Northern Wei Dynasty wrote the Book of Qi Yao Min, and put forward that "the right time, the right place, the right people, get twice the result with half the effort, and let your feelings go home, and you will get something for nothing". Weather and time play an important role in agricultural production. What is a "day"? Heaven is not the supreme master of nature and human society. Gou Zi believes that "heaven" is nature, and the change of nature has its objective law, "not for the existence of Yao, not for the death of Jie", and its change is objective. According to modern parlance, "sky" refers to the atmosphere on the surface of the universe and the earth. Various meteorological phenomena in the atmosphere, such as rain or shine, cold and warm, rain and snow, wind and frost, directly affect agricultural production. This year's grain harvest, we say "God helps"; If we cut production, we will say "God's eyes are wide open". From the perspective of agricultural production, the sky refers to meteorological conditions, more precisely, agricultural meteorological conditions. The "hour" of weather and the "hour" of agricultural activities do not simply refer to the time process, but require it to reflect the agricultural meteorological conditions and the changes of cold and warm, cloudy, sunny, rainy and snowy seasons. The solar terms in the twenty-four solar terms represent the relationship between weather changes and agricultural production throughout the year. The ancient solar terms in China were referred to as "Qi" for short, and this "Qi" actually meant weather and climate. Fundamentally speaking, the 24 solar terms are determined by the movement of the earth around the sun. Modern astronomy divides the revolution of the earth into four parts, that is, one year, and divides Sunday into 360 degrees. Starting from the vernal equinox, summer solstice is 90 degrees, autumn solstice is 180 degrees, winter solstice is 270 degrees, and then the vernal equinox is 360 degrees. Each segment is divided into six segments separated by 90 degrees. In this way, a year is divided into twenty-four segments, and the intersection of each segment is twenty-four solar terms. There are still only two points or two points in the west, which have only astronomical significance. It can be said that the 24 solar terms are a complete seasonal system that has been unique to the Chinese nation for thousands of years to express agricultural meteorological conditions. When did the twenty-four solar terms begin? It is generally believed that midsummer, midsummer, midsummer and winter solstice in Shangshu Yaodian refer to vernal equinox, summer solstice, autumn equinox and winter solstice. If so, it should be regarded as the initial stage of the formation of the twenty-four solar terms. In the seventeenth year of Zuo Gong, it was mentioned that the legend set up a calendar official: "The phoenix bird family has a correct calendar;" Xuanniao's, teacher also; Zhao Bo, Secretary Zhi Ye: Jade Bird, Secretary Zhi Ye; The Danbyrd family, the company is closed. " It is generally believed that it refers to the vernal equinox and autumnal equinox, refers to the summer solstice and winter solstice, refers to beginning of spring and Changchun, and refers to beginning of autumn and beginning of winter. In Shao Hao's time, birds were used as totems, and these images were closely related to the seasons. The mysterious bird is a swallow. The vernal equinox comes and goes, marking the arrival of the vernal equinox and the autumnal equinox. Zhao Bo, the name of this bird, is a famous bird. The solstice in summer rings until the solstice in winter, marking the arrival of the solstice in summer and the solstice in winter. Jade Bird and Dan Bird are the names of birds, marking the arrival of beginning of spring, Changxia, beginning of autumn and beginning of winter respectively. Divided into two parts and four parts, it is the most important eight qi in the 24 solar terms and the earliest eight qi. Of course, it doesn't have to go back to the legendary Shao Hao era. Although it can be traced back to 2: 00 to 2: 00, a year is divided into four periods, each period has more than 90 days, and the weather and climate in each period are significantly different, which is far from meeting the requirements of all aspects of agricultural production. So be sure to break it down. In Zuo Zhuan, there are many references to separation, arrival, opening and closing, which shows that the four sets have been around for a long time. Divide a year into eight basically equal time periods, thus determining the time range of spring, summer, autumn and winter. This can basically meet the needs of agricultural production. Lu Chunqiu recorded only eight solar terms in twelve years: beginning of spring, vernal equinox (day and night), long summer, long summer (day), beginning of autumn, autumn equinox (day and night), beginning of winter and beginning of winter (short day). It seems that there is a long stable period from division to plus four. On this basis, the 24 solar terms were formed. Huainanzi in the early years of the Western Han Dynasty recorded the complete 24 solar terms, which may be the earliest written record of the complete 24 solar terms. The order of the twenty-four solar terms is also completely consistent with modern times, and the tenth five-year plan is determined as a festival, and the solar terms are determined by the Big Dipper. Huainanzi said, "The day is once, the fifteenth day is a section, and the twenty-four hours are the change. Pointing at the children, then the winter solstice ... Plus fifteen refers to the decyl, so slight cold ... "Some people think that the twenty-four solar terms were first seen in Zhou Pian Shu Jing, and there have always been different views on the writing time of Zhou Pian. Li Changnian thought Zhou Pian Shu Jing was a book in the early Warring States period, while Qian Baoyu thought Zhou Pian was a work around 100 BC (the era of Emperor Wu of the Han Dynasty). Li Yan believes that the 24 solar terms are about the result of the first episode of Arithmetic History before the Warring States Period. Yizhoushu was discovered in the tomb of King Wei 'an during the Warring States Period, and its Shi Xun Jie completely recorded the 24 solar terms. Not only that, every breath is divided into three periods, with five days as one period, and the description of the object is very detailed. How to explain the detailed description of objects in Yi Zhou Shu Shi Xun Jie? "Zuo Zhuan Xi Gong Five Years" said: "When you leave, arrive, open and close, you must write clouds and events to prepare for the past." In other words, every two o'clock, two o'clock and four o'clock, the weather and objects at that time should be recorded as the basis for preparing various farming activities. It is a long-standing tradition of our ancestors to record celestial bodies and meteorology in detail. This is a necessary means to attach importance to agricultural production. Lu's Spring and Autumn Annals not only recorded the most important eight of the twenty-four Qi, but also recorded many natural and phenological phenomena related to the changes of temperature and precipitation. This is also a written relic of the ancestors' fine customs of recording physical objects and meteorology, which is consistent with that contained in Zuo Zhuan Xi Gong Five Years. However, this does not mean that the twenty-four spirits of the times produced by Lv Chunqiu have not yet formed. Although some people suspect that Yizhoushu was entrusted by later generations by mistake, it is still credible that all the 24 solar terms in the Warring States period were formed. We think that the order of the 24 solar terms recorded in Hanshu is slightly different from that recorded in Huainanzi, and it is determined that "the winter solstice is at the beginning of morning glory" should be regarded as the record in the early Warring States period. What needs to be clear is that the 24 solar terms were formed before the Warring States Period. The ancient calendar of China adopted the combination of Yin and Yang, that is, the cycle of the sun was taken as the year, the cycle of the moon as the month, and the leap month was used to coordinate the relationship between the year and the month. According to the position change of the sun in a year and the evolution order of the ground climate caused by it, the ancients divided the year into 24 segments and 12 months to reflect the four seasons, temperature and phenology.