After the autumnal equinox, the days get shorter and shorter.

After the autumnal equinox, the direct point of the sun continued to move from the equator to the southern hemisphere, and the days in the northern hemisphere began to shorten and the nights became longer, that is, the days in a day began to be shorter than the nights; The southern hemisphere is the opposite. Therefore, the autumnal equinox is also called the landing point.

At the North Pole and South Pole, on the day of the autumn equinox, the sun is on the horizon all day. After that, as the direct point of the sun continued to move southward, a six-month polar night began near the North Pole, which gradually expanded and then narrowed. A six-month polar day began near the South Pole, which gradually expanded and then narrowed.

At the autumnal equinox, most parts of the earth are equally divided day and night, each with 12 hours; Near the North Pole and South Pole, the sun can be observed on the horizon all day on this day.

After the autumnal equinox, the days in the northern hemisphere are short and the nights in the southern hemisphere are long. "Fen" in "Autumn Equinox" means "half". "Divide" means to divide day and night equally. Like the vernal equinox, the sun shines directly on the equator of the earth on this day, and the day and night are equally divided.