Earlier we divided the solar calendar and the lunar calendar into two phases of introduction, in order to facilitate everyone to have an intuitive comparison, we will merge the content of the previous solar calendar and the lunar calendar so that everyone can better read and understand.
Gregorian calendar
The time calendar was summarized and compiled by the ancestors through years of observation, according to the cycle of celestial movement. The one based on the lack of the moon is called the "lunar calendar", and the one based on the earth's orbit around the sun is called the "solar calendar". In this issue, we will talk to you about the relevant knowledge points of the "solar calendar" year, month and day.
Solar Year: Also known as the year of regression, it is the time when the Earth orbits the Sun in a circle, measured by the time it passes through the vernal equinox twice in a row along the ecliptic of the center of the Sun. One regression year is about 365.2422 days, or 365 days, 5 hours, 48 minutes and 46 seconds.
Solar calendar: Also known as the Gregorian calendar, solar calendar, is the world's current universal calendar standard, the earliest originated in ancient Egypt, based on the solar year time and formed.
1, solar calendar year: because the solar year is not an integer, for the unified standard, 365 days are set as the solar calendar 1 year, which is the "common year". Because a solar year is 5 hours, 48 minutes and 46 seconds more than usual, so that every cumulative 4 years will have 23 hours and 15 minutes and 4 seconds, which is about equal to 1 day, so every 4 years there will be an additional day, so the year of such an increase has 366 days, called "leap year".
Before 1582, everyone had been practicing the method of "one leap in four years", but after a leap for 4 more years, it actually leaped 44 minutes and 56 seconds more, so that every 400 years, the solar calendar year would be 3 days longer than the total solar year, so that in 400 years, there should be 3 fewer leaps. This problem has always plagued astronomers at that time, and there is no way to solve it.
Lilieus, an Italian physician and astronomer, spent 10 years researching a new calendar in 1576 and redefining the leap year: it is divided into ordinary leap years and century leap years, which are calculated as follows: the year is a multiple of 4, and not a multiple of 100, it is an ordinary leap year; the year is a full hundred, and it must be a multiple of 400 to be a leap year of the century. To sum it up, it is one sentence: "Four years a leap, a hundred years without a leap, four hundred years again." "In this way, every 400 years, what used to be 100 leap years can now be reduced by 3 times, for a total of 97 leap years. After remedying this method, the average length of the Gregorian calendar year is only 26 seconds away from the solar year, and every 3300 years, it is only one day, just reduce it by one leap year in 3300 years.
On February 24, 1582, Pope Gregory officially issued the use of the new calendar "Gregorian calendar" according to the plan of the Italian Lilieus, which is the "Gregorian calendar" commonly used in all countries in the world today. At this time, the solar calendar year and the solar year (the actual time of the Earth's transition to the vernal equinox) have been 10 days apart, in order to rematch the new calendar with the solar year, many countries in the world have adjusted the date in this year, deducting the 10 days that have been advanced in 1582, that is, the second day of October 4 (Thursday) of this year (which was supposed to be October 5) to October 15 (Friday), so that the Gregorian calendar once again coincided with the solar year, and history was artificially erased for 10 days in this year.
2, solar calendar month: refers to the current international standard of the month standard: 1, 3, 5, 7, 8, 10, 12 is a large month, 31 days a month; 4, 6, 9, 11 is a small month, 30 days a month; 28 days in a common year in February, 29 days in leap years. Seeing here is not very strange, how can there be big and small, strange and even, and a flat, how did this messy regulation come about? In fact, such a rule has no astronomical basis, has nothing to do with the moon, is completely artificially caused by the ruling class, and is only a unit of measurement.
In 45 BC, the Roman ruler Julius Caesar (Julius Caesar) reformed the calendar created by the ancient Egyptians and formulated the Julian calendar, which is divided into 12 months each year, the first, third, 5th, July, September, and November are the large months, and the large month is 31 days a month; the second, fourth, sixth, august, 10th, and December months are small months, and the small month is 30 days per month. So the year becomes 366 days, 1 day more than the actual 365 days, this is not OK, you have to subtract 1 day, from which month to subtract? At that time, Rome's regulations, the whole country to execute in February, so the Romans think that February is a fierce month, hoping that February is shorter, so they decided to subtract 1 day from February, so February became 29 days, February in the usual year is 29 days, leap years 30 days, this is the current world common "Gregorian calendar" the earliest prototype. After his death, people named him Julius July (the origin of July July).
In 27 BC, Caesar's righteous son Octavian became head of Rome and was given the title of "Augustus". Because Caesar was born in July, which belongs to the big month, and he was born in August of the small month, in order to be indistinguishable from Caesar, he ordered that August be changed to a large month, and September and November were changed to a small month, and October and December were changed to a large month. With this change, 1 more day per year became 366 days, so he also subtracted 1 more day from February, so that February became 28 days in the usual year and 29 days in leap years. This is the origin of the current solar month standard. In keeping with Caesar, Octavian also named August after himself (the origin of August August in English).
3, solar calendar day: the earth rotates in a circle of about 23 hours, 56 minutes and 4 seconds. The Earth's rotation rate is not permanent, increasing or decreasing by about three thousandths to four thousandths of a second every 10 years. Because the time for the earth to rotate is not an integer, in order to unify the standard, the agreement is 24 hours a day, so that the rotation time is about 4 minutes less than the standard 24 hours per day, almost every 4 years just one more day, in order to ensure balance, so there is a 1 leap year every 4 years.
China began to use the solar calendar from 1912: the year after the outbreak of the Xinhai Revolution (1912), the government of the Republic of China at that time adopted the solar calendar as the national calendar, and in terms of chronology, the Common Era chronology and the Republic of China chronology were parallel.
On September 27, 1949, after the first plenary session of the Chinese Political Consultative Conference, the newly established People's Republic of China used the Gregorian calendar and the Common Era commonly used by most countries in the international community as calendars and chronology. However, the lunar calendar has not been abolished, and today's traditional Chinese festivals are still based on the lunar calendar.
Advantages of using the solar calendar:
1, the time is precise, by calculating every 3333 years there will be a day of error.
2. The solar calendar is fixed for 12 months per year, and the number of days in each calendar month is fixed; the leap year is simple to calculate, and the leap year only adds one day (29 days) in February, which is easy to remember.
3. China's "twenty-four solar terms" are determined according to the orbit of the earth around the sun, and it is also one of the earliest countries in the world to use the solar year. Depending on the sun starting from the vernal equinox, at this moment the sun shines vertically on the equator, each 15 degrees forward is a solar term, and the running week returns to the vernal equinox, which is a return year, and the 24 solar terms are exactly 360 degrees.
4, the solar calendar year is basically the same length as the solar year, the change of the four seasons is also because of the sun rotation, so the seasonal change time is basically fixed every year.
5, the world synchronization: at present most countries use the solar calendar, easy to communicate and exchange.
Lunar/lunar calendar
From ancient times to the present, there are masculine and strong, hot sun; to yin is soft, the moon is hazy. Human society has been progressing around the sun and the moon. The so-called solar calendar is a calendar summarized and formulated with the sun as a reference; the so-called lunar calendar is a calendar formed with the moon as a reference, and the calendar based on the lack of the moon is called the lunar calendar.
Lunar calendar: The full name is the lunar calendar, that is, the time of the moon circumnavigating the earth (the moon is a round cycle) is one month, lasting 29 days, 12 hours, 44 minutes and 2.8 seconds, orbiting 12 weeks for 1 year, lasting 354 days 8 hours 48 minutes 33.6 seconds.
Islamic calendar: Belongs to the pure lunar calendar, since its creation for 14 centuries, it has been used by Arab countries and Muslims around the world as a religious calendar. The Islamic calendar defines the odd-numbered months (January, March, May, July, September, and November) as "mega-construction" for 30 days per month, and even-numbered months (February, April, June, August, October, and December) as "minor construction" for 29 days a month. Because the whole number is taken more than 8 hours a year, in order to maintain balance, the calendar is solved by setting a leap year: 30 years as a cycle, the 2nd, 5th, 7th, 10th, 13th, 16th, 18th, 21st, 24th, 24th, 24th, 29th year in each cycle, a total of 11 years as leap years, plus 1 leap day at the end of December in each leap year, 355 days in leap years, and 354 days in each 19th year as a common year.
The Islamic calendar was officially introduced to China during the Yuan Dynasty (1267 AD) and is called the "Hijri calendar" for use by Muslims. The calendars of the Ming Dynasty and the early Qing Dynasty were formulated with reference to this calendar, and the influence on China's calendar was as long as 400 years. Muslims of all ethnic groups in our country who profess Islam still use this calendar as a basis for calculation in their religious activities to this day.
In 622 AD, the Prophet of Islam, Muhammad, led Muslims from Mecca to Medina, and in order to commemorate this historical event, he designated this year as the era of the Islamic calendar, and July 16, 622 AD is the New Year's Day of the first year. Because the lunar calendar and the international solar calendar are not the same number of days, the difference between the Islamic calendar and the Gregorian calendar is still relatively large, taking the article date as an example: today is August 27, 2021, while the Islamic calendar is today is January 18, 1443.
Lunar calendar: Originated in the Xia Dynasty, so it is also called "Summer Calendar". We already know that the solar calendar has about 365 days in 1 year, about 354 days in 1 year in the lunar calendar, and about 11 days less in the solar calendar than in 1 year in the solar calendar, so that every 3 years or so, the lunar calendar will be 1 month less than the solar calendar. In order to maintain the balance of yin and yang, people came up with ways to increase the leap month, the purpose is to make the average number of days in the lunar calendar match the number of days in the solar calendar. It can be seen that the lunar calendar is a calendar based on the lunar calendar and formed by integrating the laws of the solar calendar, so it belongs to the yin-yang calendar, and its years are divided into ordinary years and leap years, with 12 months in the ordinary year and 13 months in leap years.
Origin of the first month: There have been many versions of the first month of China's history: the Xia Dynasty took the Summer Calendar Mengchun as the First Month, the Shang Dynasty took the December of the Summer Calendar as the First Month, the Zhou Dynasty took the November of the Summer Calendar as the First Month, and the Qin Dynasty and the Early Han Dynasty once took the October of the Summer Calendar as the First Month, which is the origin of the saying "Xia Calendar Jianyin, Shang Calendar Jian ugly, Zhou Calendar Jianzi, Qin Calendar Jianhai" (dry branch calendar name). Since Emperor Wu of the Han Dynasty re-used "Xia Zheng", it has been used for generations to this day. Xia Zheng, the abbreviation of the "first month of the summer calendar", takes Meng Chun (spring January) as the first month. Mengchun is the first month of spring, which refers specifically to the period from spring to sting. The lunar calendar year is divided into twelve months, in order: MengChun, Mid-Spring, Jichun, Mengxia, Midsummer, Jixia, Mengqiu, Mid-Autumn, Jiqiu, Mengdong, Midwinter, Jidong.
Origin of the lunar calendar title: Before the Republic of China, the imperial society, in fact, everyone called the Chinese calendar "imperial calendar", which is the legal title; after the overthrow of the feudal rule of the Republic of China, the title of the imperial calendar was banned, and since then the old calendar, the old calendar, the lunar calendar and other terms have been generally used; on New Year's Day in 1968, it is roughly because of the destruction of the four old, and the People's Daily first used the title of "lunar calendar", and since then it has been renamed the lunar calendar. In fact, in the national standard, "traditional Chinese calendar" is the formal expression of the lunar calendar.
Lunar day calculation: The average time of the moon around the earth is about 29.5 days, so the number of days in each month is uncertain, and the number of days in the year is different. In the current Chinese calendar, the New Year must be the first day of the lunar calendar, as long as the first day of each month is found, then the interval between the two first days can determine the size of the month and the size of the month. The average cycle of the synodic month is 29.5 days, and if this month starts from the new moon and starts with the new moon next month, less than 30 days, then it is counted as 29 days of the small month; if it exceeds 30 days, it is counted as the 30 days of the large month. The lunar calendar also has to maintain balance with the solar calendar, so every few years to add 1 leap month, the increase in leap months is not fixed, need to consider from the season seasons and other aspects, the current use of 19 years 7 leap method: in the 19 years of the lunar calendar, stipulate 12 common years, every 1 flat year 12 months; there are 7 leap years, every 1 leap year 13 months. How many days per month and when to increase the leap month are based on astronomical calculation results, and are calculated according to the calendar, so the size of the month is not necessarily crossed, and the leap month will not be fixed. In order to facilitate the use of the lunar calendar, many scholars have calculated in advance and released the well-known "perpetual calendar".
Countries where the lunar calendar is used: In addition to China, several countries deeply influenced by Han culture also use the lunar calendar, mainly Japan, North Korea, South Korea, Vietnam, Malaysia, Singapore, Mongolia, Myanmar and other countries, but now they are basically used by the people, and the official has almost been abolished. Vietnam is relatively more used, And Vietnamese people are like us, there are also twenty-four festivals in the year, and also celebrate the Spring Festival, and many customs are similar to ours.
Advantages of the lunar calendar:
1, the date is consistent with the moon phase: from the new moon to the full moon to the residual moon, by observing the fullness of the moon, you can roughly know the lunar calendar date.
2, the tide rise and fall: the tidal phenomenon is greatly affected by the gravitational force of the moon, human beings by observing the changes in the moon to calculate the time of the tide coming and going, is conducive to navigation, fishing, flood control and other work.
Disadvantages of the lunar calendar:
1, because the lunar calendar does not consider the earth's orbit around the sun, so according to this law calendar, each year will be about 11 days less than the solar calendar, with the passage of time, the gap will continue to increase, the change of the four seasons can not be fixed in the lunar calendar, the lunar calendar can not reflect the seasons.
2, agricultural production is based on the solar calendar, China's twenty-four solar terms are based on the solar calendar and formulated, so the lunar calendar can not meet the requirements of agricultural production.
3, the date of the lunar calendar has no fixed relationship, so it is not easy to remember, it is not conducive to use.
![Tell you what you didn't know about leap years[fig]](data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACwAAAAAAQABAAACAkQBADs=)