Compare the characteristics of four solar terms in China: the time of solar terms and the length of day and night at the direct point of the sun (northern hemisphere): spring equinox, autumn equinox,

Compare the characteristics of four solar terms in China: the time of solar terms and the length of day and night at the direct point of the sun (northern hemisphere): spring equinox, autumn equinox, summer to winter. Equinox 2 1 equal day and night; On September 23, the autumnal equinox was divided equally between day and night; June 22nd, the summer solstice, has long days and short nights. Winter solstice is 65438+February 22nd, with short days and long nights.

As for the origin of the 24 solar terms, in the Spring and Autumn Period, the four seasons were designated as: midsummer, midsummer, midsummer and midsummer. The twenty-four solar terms are divided according to the position of the sun on the ecliptic (that is, the orbit of the earth around the sun).

In BC 104, the taichu calendar written by Deng Ping officially set 24 solar terms in the calendar, and defined the astronomical position of the 24 solar terms. Depending on the sun starting from the vernal equinox (longitude zero, at this moment the sun shines vertically on the equator), every advance of 15 degrees is a solar term; After a week's operation, I returned to the vernal equinox, which is a tropical year with 360 degrees, so it is divided into 24 solar terms. The dates of solar terms are relatively fixed in the solar calendar. For example, beginning of spring in the solar calendar always falls between February 3rd and 5th.

As an intangible heritage, the 24 solar terms are also related to the zodiac, that is, corresponding to the western constellations. The relationships are as follows: Aries corresponds to the spring equinox, Taurus to the light snow in Grain Rain, Gemini to the full summer solstice, Cancer to the summer solstice, Leo to the summer solstice, Virgo to the autumn equinox, Libra to the first frost, Scorpio to the first frost and light snow, Sagittarius to the winter solstice in Yu Xiaoxue, Capricorn to the winter solstice, Aquarius to the severe cold and rain, and Pisces.