Can you understand the vernal equinox, autumnal equinox, summer solstice and winter solstice?

The long summer has just passed, which indicates that we have bid farewell to spring and entered summer. There are 24 solar terms in China, and our seasonal division is judged according to the solar terms. The autumnal equinox refers to the middle boundary of autumn, and it is also the thickest time in autumn. Corresponding to the autumnal equinox are the vernal equinox, the summer solstice and the winter solstice. How much do you know about these solar terms?

Vernal equinox: the fourth of the 24 solar terms, March 20th or 21; Mid-spring, the length of day and night is equal.

Summer solstice: the tenth of the 24 solar terms, June 2 1 or 22; It means that the heat is coming, with the longest day and the shortest night.

Autumnal equinox: the sixteenth day of the twenty-four solar terms, September 23rd or 24th; It means that in the crisp autumn, day and night are equal.

Winter solstice: the 22nd solar term in 24 solar terms, which falls on 65438+February 20th or 22nd, 265438+; It means that winter is coming, with the shortest day and the longest night.

Vernal equinox:

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, theoretically, most parts of the world are as long as day and night, and the North Pole (90 north latitude? ) and the South Pole (90 south latitude? The special phenomenon that the sun circles around the horizon all day can be observed nearby. After the vernal equinox, the days in the northern hemisphere are long and the nights are short (the days are longer than the nights), and the days in the southern hemisphere are short and the nights are long (the days are shorter than the nights). 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.

Summer solstice:

Summer solstice is one of the 24 solar terms, which occurs on June 2 1 or 22 of the Gregorian calendar every year. On the day of summer solstice, the sun moves to 90 degrees of the yellow meridian (summer solstice, currently in Gemini), and the position where the sun directly hits the ground reaches the northernmost point of the year, almost directly to the Tropic of Cancer. At this time, the daylight hours in all parts of the northern hemisphere reach the longest in the whole year. For the Tropic of Cancer and its northern area, the summer solstice is also the highest day of the year at noon. In Beijing, the daytime from summer solstice can be as long as 15 hours, and the sun is as high as 73? at noon. 32? . On this day, the northern hemisphere gets the most sunshine, almost twice as much as the southern hemisphere.

Autumnal equinox:

The sixteenth solar term in the twenty-four solar terms of the lunar calendar at the autumnal equinox is usually from September 22nd to 24th every year. The climate in the south began to decline from this solar term. First, on this day, the sun reached the longitude of the Yellow River 180 degrees, and directly hit the equator of the earth. Therefore, in most parts of the earth, 24 hours are divided equally, each being 12 hours. At the North Pole (90 north latitude? ) and the South Pole (90 south latitude? On this day, we can observe the special phenomenon that the sun circles on the horizon all day. After the autumnal equinox, the northern hemisphere has shorter days and longer nights (shorter days than nights), while the southern hemisphere has longer days and shorter nights (longer days than nights).

Winter solstice:

Winter solstice is an important solar term in the China lunar calendar, and it is also a traditional festival of the Chinese nation. The solstice in winter is usually called Winter Festival, Long Festival and New Year's Eve. As early as more than 2,500 years ago in the Spring and Autumn Period, China had observed the sun with the earth and determined the winter solstice, which was the earliest of the 24 solar terms, and the time was between 65438+February 265438+February 0-22 in the Gregorian calendar. The ancient saying about the winter solstice is: when the cathode arrives, the yang begins to grow, the sun goes south, the day is short and the shadow is long, so it is called the winter solstice.