The origin of vernal equinox

The origin of the vernal equinox is as follows:

The vernal equinox begins on March 20th (or 2 1) and ends on April 4th (or 5th) every year. The vernal equinox begins on March 20 or 2 1 day of the solar calendar every year, and the sun reaches 0 degrees of the yellow meridian (vernal equinox). The length of day and night is average, just half of the 90th day of spring, so it is called "vernal equinox".

On the vernal equinox, the sun shines directly at the equator, and day and night are almost equal. Then the direct sunlight position gradually moved northward, and the days were long and the nights were short. The vernal equinox is an important solar term, which not only has astronomical significance: the northern and southern hemispheres are equally divided day and night; Climatically, there are also obvious characteristics. At the vernal equinox, except the Qinghai-Tibet Plateau, the northeast, the northwest and the northern part of North China, China entered a beautiful spring.

Astronomical phenomena of vernal equinox;

At the vernal equinox, the bucket handle of the Big Dipper points due east, and the sun reaches 0 degrees of the yellow meridian. The festival will be held on March 20th or March 2nd1day of the Gregorian calendar. The vernal equinox solar term usually refers to a certain period of time, that is, the sun is located between 0 degrees and 15 degrees of the yellow meridian, from March 20 to April 5 of the Gregorian calendar.

In ancient times, the vernal equinox was also called "Japan-China", "Day and Night Equinox" and "Midspring Moon". Because the sun shines directly on the equator on this day, the days in the northern hemisphere and the southern hemisphere are as long as the nights. After the vernal equinox, the direct sunlight position gradually moved northward.