What is the vernal equinox? Is this the beginning of spring?

The vernal equinox is one of the 24 solar terms and the midpoint of 90 days in spring. The Gregorian calendar date is around March 21(20th to 22nd) every year. In ancient times, the day when the sun reached the 0 (vernal equinox) longitude of the Yellow River was also called "Japan-China", "Day and Night" and "Midspring Moon".

The spring equinox is not the beginning of spring, but the beginning of spring.

1, astronomical phenomena

In terms of time period, it means that the sun is located in the interval from 0 to 15, which is about March 20 to April 4 of the Gregorian calendar. But it usually refers to the day (or moment) when the sun hits the equator directly. Simply put, the sun shines directly on the equator, and the day is as long as the night, which is the equinox of day and night. The sun began to move towards the Tropic of Cancer.

2. Earth phenomenon

At the vernal equinox, the direct point of the sun is on the equator, and then the direct point of the sun continues to move northward, so the vernal equinox is also called the ascending equinox.

At the vernal equinox, except near the pole, the world's day and night are almost the same length. After the vernal equinox, the days in the northern hemisphere are getting longer and shorter, and the nights in the southern hemisphere are getting shorter and shorter.

At the vernal equinox, there are no extreme days and nights in the world. After the vernal equinox, it began to be extremely daytime near the North Pole, and its scope gradually expanded. Near the Antarctic, the extreme day ends and the extreme night begins, and the scope gradually expands.

The sunshine at the vernal equinox, when the length of day and night is the same all over the world.