The traditional food of autumnal equinox includes: autumn vegetables, eggs, dumplings, crabs, radishes, etc. Autumn vegetable is a kind of wild amaranth. Villagers call it "autumn green Artemisia". On the day of the autumn equinox, the whole village goes to pick autumn vegetables. There is also the custom of "erecting eggs" in the autumn equinox every year. Of course, after "erecting eggs", it is necessary to eat eggs.
The autumnal equinox is the 16th of the 24 solar terms and the fourth in autumn. On the autumnal equinox, "Fen" means "equinox" and "half". On the autumnal equinox, the sun is almost direct at the equator of the earth, and the length of day and night is the same all over the world. After the autumnal equinox, the position of direct sunlight moves to the southern hemisphere. The northern hemisphere gets less and less solar radiation, but more heat is lost on the ground, and the speed of temperature reduction is significantly accelerated.
After the autumnal equinox, the direct point of the Sun continues to move from the equator to the southern hemisphere, and the days in the northern hemisphere begin to be shorter and the nights longer, that is, the days begin to be shorter than the nights in a day; The southern hemisphere is opposite. Therefore, the autumnal equinox is also called drop. At the north and south poles, on the autumnal equinox, the sun is on the horizon all day.
Since then, with the continuous southward movement of the direct point of the sun, a six-month polar night began near the Arctic, and the range gradually expanded and then narrowed; A six-month polar day began near the south pole, and the range gradually expanded and then narrowed.