What is the vernal equinox? Vernal equinox is the intersection of the celestial equator and the ecliptic on the celestial sphere, which are two opposite points. The origin of the word traceability comes from the Latin aequinox, which means equal day and night. In fact, it is also the case. When the sun passes through vernal equinox, day and night are the same all over the earth, each with 12 hour.
The vernal equinox solar term (about 2 1 year in March) starts on March 20th (or 2 1 year) and ends on April 4th (or 5th). 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; In climate, it also has obvious characteristics.
During the spring equinox, China has entered a beautiful spring scenery except the Qinghai-Tibet Plateau, Northeast China, Northwest China and North China. On the vast land, willows are green, Fei Ying grass grows, wheat jointing and rape blossoms are fragrant.
The autumnal equinox solar terms (around September 23rd) According to the ancient book "Spring and Autumn Dew, Yin and Yang in and out of the upper and lower chapters", "The autumnal equinox, Yin and Yang are also half-phase, so it is cold and summer day and night." The autumnal equinox is the16th solar term among the 24 solar terms of the lunar calendar, which usually falls on September 22nd or 23rd every year. On the day of the autumnal equinox, the sun reaches 180 degrees, and the sun shines directly on the equator of the earth, so the day is divided into 24 hours.
There is no extreme day and night phenomenon in the world. Autumn wind and autumn rain make people sad. This season, due to climate change, the temperature drops, the sunshine decreases, people's emotions are easily affected, and the human body will also have various "autumn dryness" symptoms. Therefore, this season's health care pays attention to convergence, and it is appropriate to go to bed early and get up early in daily life.