When did the twenty-four solar terms originate?

The spring rain shakes the spring and clears the valley, and the summer is full of mountains and summers. Autumn dew, autumn frost, little snow in winter and cold in winter. The two festivals remain unchanged every month, with a maximum difference of one or two days. The first half of the year is June 2 1 day, and the second half is August 23.

I believe that the song "Twenty-four solar term song" can be catchy, so we know that there are twenty-four solar terms, but where did it come from? Let's take a look at Yi.

In the ancient history of China, we all know that there are the so-called Book of Changes and Eight Diagrams, and so are the twenty-four solar terms, all of which are the crystallization of ancient wisdom. They divided the year into twenty-four equal parts according to the law of the operation of heaven and earth and the changes of the four seasons, and each equal part represented a solar term. At the same time, they named the sun's trajectory "Zodiac" and drew a circle according to the ecliptic, each circle was 15, just 24 minutes.

According to relevant historical records, the earliest saying was that it was gradually improved in the Eastern Zhou Dynasty, before and after the Spring and Autumn Period and the Warring States Period, and it had a unique title. The earliest recorded book Lu's Spring and Autumn Annals has been written by beginning of spring, Chang Xia, beginning of autumn and beginning of winter, which clearly shows the cyclical changes throughout the year.

Later, in the Qin and Han Dynasties, the 24 solar terms were officially named, and the names of the solar terms in the book Huainanzi were exactly the same as now, so it can basically be concluded that in the long river of more than 3,000 years, the 24 solar terms are still relatively resistant to playing, and it is estimated that they can persist until now.

In BC 104, when Deng Ping compiled taichu calendar, he determined the astronomical position of the 24 solar terms and put them into the calendar, which was very resistant. Therefore, no matter how time passes, it is always engraved in our bones.

In fact, the 24 solar terms were originally determined according to the position of the Big Dipper, which includes Shu Tian, Tian Xuan, Tianji, Tianquan, Yuheng, Kaiyang and Yaoguang. Ancient people relied on it to distinguish directions and solar terms, that is, the so-called "bucket handle refers to the east, and the world is spring; Guide to barrel handle, it's summer in the world; Bucket handle refers to the west, and the world is autumn; Bucket handle refers to the north, and it is winter all over the world. Because the 24 solar terms are determined by the rotation direction of Beidou bucket handle, this calendar is also called "ephemeris".

I don't know if you have learned it.