What is the origin of the autumnal equinox solar terms?

The autumnal equinox is a solar term established by the ancients around September 23 every year. At this time of the year, the sun will be located at 180 degrees, and China will enter the "autumnal equinox" solar term. The autumnal equinox, like the vernal equinox, is the earliest solar term established by the ancients. "Spring and Autumn Stories Yin and Yang in and out" records: "The autumnal equinox is accompanied by Yin and Yang, so it is cold and summer day and night."

Brief introduction of autumnal equinox

The autumnal equinox is the sixteenth solar term among the twenty-four solar terms and the fourth solar term in autumn. Struggle with yourself; The sun reaches the yellow meridian180; Celebrated on September 22-24 of the Gregorian calendar every year. On the day of the autumnal equinox, the sun shines almost directly on the equator of the earth, and the length of day and night is equal all over the world.

The autumnal equinox means "equally divided" and "equally divided", which means equally dividing autumn except day and night. After the autumnal equinox, the position of direct sunlight moves south, and the days in the northern hemisphere become shorter, the nights become longer, the temperature difference between day and night increases, and the temperature drops day by day.

The autumnal equinox used to be the traditional "Festival to offer sacrifices to the moon", and the Mid-Autumn Festival evolved from offering sacrifices to the moon in autumn. On June 2nd, 2065438, the State Council issued an official reply on the establishment of "China Farmers Harvest Festival", agreeing to set the annual autumn equinox as "China Farmers Harvest Festival" from June 20th, 2065438. The festival activities mainly include cultural performances and agricultural competitions.