What does the vernal equinox stand for?

The vernal equinox means that day and night are almost equal. The vernal equinox is the fourth of the 24 solar terms and an important season for farming. The sun shines directly on the equator of the earth, and day and night are almost equal. In ancient times, it was spring from beginning of spring to long summer, and the vernal equinox was in the middle of three months in spring. The sun reaches the longitude of the Yellow River at 0 degrees, in March every year in Gregorian calendar 19~22. "The vernal equinox, Yin and Yang. So it's hot and cold day and night. " According to the lunar calendar, "it refers to the vernal equinox, which is about Sunday. The northern and southern hemispheres are equally divided day and night, which is also half of spring, so it is called the vernal equinox." From this day on, the direct position of the sun gradually moved northward, and the length of day and night in the northern and southern hemispheres also changed. The northern hemisphere has long days and short nights, but the southern hemisphere is just the opposite.