What are the 24 solar terms? Urgent! ! !
As early as the Spring and Autumn Period and the Warring States Period, China was able to measure the length of the sun's shadow at noon with a soil gauge (a pole was erected on the plane), thus determining four solar terms: winter solstice, summer solstice, vernal equinox and autumn equinox. In a year, the shortest day of the noon soil return shadow is the summer solstice, the longest day is the winter solstice, and the shadow with moderate length is the vernal equinox or autumn equinox. The Book of History in the Spring and Autumn Period recorded the solar terms. The twenty-four solar terms are completely recorded in Huainanzi written by Liu An in the Western Han Dynasty. In ancient China, the lunar calendar was used to record time, and the solar calendar was used to divide the 24 solar terms of spring, summer, autumn and winter. Our ancestors called five days 1, and three days were called solar terms. The whole year was divided into 72 days out of 24 solar terms.
With continuous observation, analysis and summary, the division of solar terms is gradually enriched and scientific. By the Qin and Han dynasties more than 2000 years ago, a complete concept of 24 solar terms had been formed.
In ancient times, a year was divided into twelve months, and each month had two solar terms. The former is solar terms, while the latter is neutral. For example, beginning of spring is the first month's festival, and it rains in the first month. Later generations called solar terms and neutral gas solar terms.
The names of the 24 solar terms are: beginning of spring, Rain, Sting, Vernal Equinox, Qingming, Grain Rain, Changxia, Xiaoman, Mangzhong, Summer Solstice, Xiaoshu, beginning of autumn, Chushu, Bailu, Autumnal Equinox, Cold Dew, Chufrost, beginning of winter, Light Snow, Winter Solstice, Slight Cold and Severe Cold.
Rain in early spring (February 3-5) (February 18-20)
Equinox (March 5th to 7th) (March 20th to 22nd)
Tomb-Sweeping Day (April 4 -6) Grain Rain (April 19-2 1)
Long Summer (May 5 -7) and Xiaoman (May 20 -22)
Summer solstice (June 5-7) (June 265438 +0-22)
Summer (July 6-8) and summer (July 22-24)
Beginning of autumn is in summer (August 7 -9) (August 22 -24).
Millennium (September 7-9) Autumnal Equinox (September 22-24)
Cold dew (65438+1October 8-9) first frost (65438+1October 23-24)
Beginning of winter (165438+17-8 October) Xiaoxue (165438+122-23 October)
Heavy snow (65438+February 6-8) Winter solstice (65438+February 265438+February 0-23)
Slight cold (65438+1October 5-7) Great cold (65438+1October 20-2 1)
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). 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. However, in the lunar calendar, the date of solar terms is not easy to determine. Take beginning of spring as an example. It can be the first day of the lunar calendar in the previous year, 65438+February 15, and the latest is the first month, 15.
It can be seen from the naming of the twenty-four solar terms that the division of solar terms fully considers the changes of natural phenomena such as seasons, climate and phenology. Among them, beginning of spring, Changxia, beginning of autumn, beginning of winter, vernal equinox, autumnal equinox, summer solstice and winter solstice are used to reflect seasons, and a year is divided into four seasons: spring, summer, autumn and winter. The vernal equinox, autumnal equinox, summer solstice and winter solstice are divided from an astronomical point of view, reflecting the turning point of solar height change. Beginning of spring, Changchun, beginning of autumn and beginning of winter reflect the beginning of the four seasons. Because China is a vast country with a very obvious monsoon and continental climate, the weather and climate vary greatly from place to place, so the four seasons in different regions are also very different.
The five solar terms of slight summer heat, great summer heat, slight cold and severe cold reflect the change of temperature and are used to express the degree of heat and cold in different periods of the year; Rain, Grain Rain, light snow and heavy snow reflect the phenomenon of precipitation, indicating the time and intensity of rainfall and snowfall; The three solar terms, White Dew, Cold Dew and First Frost, on the surface reflect the phenomenon of condensation and condensation of water vapor, but in essence reflect the process and degree of gradual temperature drop: when the temperature drops to a certain extent, water vapor condenses; The continuous drop in temperature not only increases condensation, but also gets colder and colder; When the temperature drops below zero degrees Celsius, water vapor condenses into frost.
Xiaoman and awn seeds reflect the maturity and harvest of related crops; Frightening and Qingming reflect natural phenological phenomena, especially stinging, which indicates that spring will return with the recovery of early thunder in the sky and underground stinging insects.