When is the early spring now? How was beginning of spring accurate to the second in ancient times?

Introduction: beginning of spring is the first of the 24 solar terms, so its position in everyone's mind is very high. Besides, beginning of spring is very close to the Spring Festival, so everyone is very concerned about the time in beginning of spring. So when is the beginning of spring? Nowadays, it is easy for us to query the solar term time to the minute, so how was beginning of spring accurate to the second in ancient times? Come and have a look with me.

When is the early spring now?

Beginning of spring, one of the 24 solar terms, is also called "Da Chun". "Li" means "start". China takes beginning of spring as beginning of spring, and on February 4th or 5th every year, when the sun reaches longitude 315th, it is beginning of spring. Twenty-four solar terms: "The solar terms in the first month will stand, and long summer will have the same long summer as autumn and winter.

The origin of beginning of spring

Beginning of spring, as a festival, existed as early as the Spring and Autumn Period. At that time, there were eight festivals in a year, namely beginning of spring, Changxia, beginning of autumn, beginning of winter, Vernal Equinox, Summer Solstice and Winter Solstice. Twenty-four solar terms were recorded only in the Book of Rites and the Monthly Order by Liu An in the Western Han Dynasty and the Xunzi of Tian Zi in Huainan.

Before the Han Dynasty, the calendar had been changed many times. At that time, beginning of spring among the 24 solar terms was designated as the Spring Festival, which meant that spring began. This title lasted for more than 2000 years, until 19 13, when the national government officially issued a document, making it clear that the first day of the first month of the first month of each year was the Spring Festival.

Since then, beginning of spring has only existed as one of the 24 solar terms, and it has been passed down to this day.

How was beginning of spring accurate to the second in ancient times?

In order to find out this problem, we have to mention a word: ecliptic (are children born after 80 who like saints familiar with it? We will mention later), the ecliptic is the visual path that people on earth take when they look at the sun among the stars in a year. Simply put, the earth revolves around the sun once a year. From the earth, we can see that the sun moves 365 or 366 times a year in the sky. The trajectory of the sun's movement in this way is called the ecliptic-it is an imaginary great circle on the celestial sphere, which is the projection of the earth's orbit on the celestial sphere. The ecliptic plane and the equatorial plane intersect at two points, namely, the vernal equinox and the vernal equinox.

As the name implies, when the sun is at the "vernal equinox", it is the "vernal equinox" among the 24 solar terms. The vernal equinox is the midpoint of spring in the northern hemisphere, which occurs on March 20th or March 20th of 2 1 year. This day is as long as day and night, so it is called "vernal equinox". Simply put; The vernal equinox and autumnal equinox are the moments when the sun shines directly on the equator of the earth.

The twenty-four solar terms reflect the movement of the sun in one year, and are divided according to the position of the sun on the ecliptic. Depending on the sun from the vernal equinox (longitude zero, at this moment the sun shines vertically on the equator), every advance of about 15 degrees is a solar term; After running for a week, I returned to the vernal equinox. Beginning of spring is a solar term in which the sun is located at 3 15 degrees of the Huangjing.

The exact time to calculate the solar terms. Zhang Xi, director of the Science Popularization Department of Purple Mountain Observatory of Chinese Academy of Sciences, once said in an interview with domestic media that this accurate time is the result of calculation by the calendar department of Purple Mountain Observatory of Chinese Academy of Sciences. Moreover, the exact time of the 24 solar terms every year will be calculated one or two years in advance and published in the China Astronomical Calendar published by the Observatory. This is a complex operation, not only to calculate the speed and angle of the sun and the earth, but also to consider the gravitational effect of other celestial bodies in the whole solar system, not only a few planets, but even small celestial bodies. In order to calculate the interaction between these celestial bodies, simple Newton gravity is not enough, and a more advanced theory of physical gravity should be introduced.

Fortunately, computers are powerful enough now. Xu Jianwei, a translator of astronomical algorithms, once wrote an article introducing these algorithms in detail. He said that before the advent of computers, the calculation of the 24 solar terms was very complicated. With the popularization of computers and the Internet, the National Aeronautics and Space Administration of France and the Paris Observatory published their own precise ephemeris calculation methods on the Internet, which made it possible for people to calculate the lunar calendar. The reporter learned that the "Wanshou Calendar" designed by Mr. Xu Jianwei is a calendar with very high accuracy, which is realized by advanced algorithms, and its accuracy is comparable to that of the "Sun Shuttle Calendar" made by the National Time Service Center of Chinese Academy of Sciences.

Then, China people farm by 24 solar terms, and what do foreign countries farm by? In Japan, the twenty-four solar terms imported from China are still in common use, which are inseparable from people's daily life, and even the names of the solar terms are exactly the same. Similar to the twenty-four solar terms, the twelve zodiac signs in ancient Babylon were also divided into 12 equal parts based on the vernal equinox, so the twelve constellations in astrology (in essence, the twelve zodiac signs) coincided with the twelve China qi in the twenty-four solar terms, corresponding one by one.

Of course, there have been some less accurate calendars in the world, such as the "* * * and calendar" during the French Revolution. All the year round,1February, 30 days a month, every 10 day is ten days, and every ten days 10 day is a rest day. /kloc-The remaining five days except 0/2 months are regarded as "China Day without pants". * * * and the names of calendars are very poetic: such as Portuguese moon, foggy moon, frosty moon and snowy moon. However, * * * and the calendar are too divorced from reality. Its time unit is decimal, with ten days for ten days, ten hours for one day, one hour for one hundred minutes and one minute for one hundred seconds, which can't fit the life of ordinary people, so it failed.

The current international calendar, which is what we call the "solar calendar", is actually the Gregorian calendar, which originated in western society. It was first reformed by Italian doctor, astronomer aloysius Lilius and other scholars on the basis of julian calendar, and then promulgated by Pope Gregory XIII in 1582. AD is the "Gregorian calendar era", also known as "AD".

On September 27th, 1949, the first plenary session of China People's Political Consultative Conference adopted 1949, and our country also adopted the Gregorian calendar and AD as the calendar and calendar year. But in China, the 24 solar terms with a history of 3,000 years are still used to guide agricultural production.