How did the first day of the Gregorian year come about?

The year is a unit of time, generally speaking, it is fixed, in ancient times, due to the needs of agriculture, it can only use a relatively fixed unit of time, so it is probably the case that it has been developed and inherited. If it is not basically fixed, it can't be used to predict spring or anything, and spring is generally coming in those days, if the two times are changing, the error is not greater, and it is not conducive to the development of agriculture, and the ancient people are still quite smart. The Gregorian calendar should only be an official time, it would be better to unify it, otherwise it would be quite complicated, the lunar calendar and astronomy are very closely related to the lunar calendar, and the relationship with the Gregorian calendar should not be very close.

The Gregorian calendar has 365 or 366 days in a year

The number of days in a year in the Gregorian calendar depends on the situation. There are 365 days in a common year and 366 days in a leap year. There are 365 days in a normal year, and from January to December, they are 31 days, 28 days, 31 days, 30 days, 31 days, 31 days, 30 days, 31 days, 31 days, and 31 days.

The number of days in each month can be added together.

There are 366 days in a leap year, and the months from January to December are 31 days, 29 days, 31 days, 30 days, 30 days, 31 days, 31 days, 31 days, 31 days, and 31 days. The number of days in each month can be added together.

Causes of leap years

The Earth's orbit around the Sun is 365 days, 5 hours, 48 minutes and 46 seconds (conjunction), which is a return year. The common year of the Gregorian calendar is only 365 days, which is about one day shorter than the return year, and the remaining time is about one day accumulated every four years, so one day is added at the end of February of the fourth year to make the length of the year 366 days, and this year is a leap year.

There are 97 leap years in the current Gregorian calendar every 400 years. If a leap year is calculated every four years, an average of more days are counted per year, so that after 400 years, about three more days will be calculated. Therefore, every 400 years there is a reduction of 3 leap years.

Therefore, the Gregorian calendar stipulates that when the year is an integer hundred, it must be a multiple of 400 to be a leap year; A century year that is not a multiple of 400, and even a multiple of 4 is not a leap year.

The time is uncertain, sometimes once every two years, sometimes once every 3-4 years, irregular.

The lunar calendar is based on the summer calendar.

Lunar calendar) is a kind of calendar based on the solar calendar. Therefore, in the strict sense of the word, China's lunar calendar should not be called a lunar calendar, but a luni-solar calendar.

The lunar calendar is a lunisolar calendar: its years are divided into ordinary years and leap years. Twelve months in a normal year; Leap years are thirteen months.

Months are divided into major months and minor months, with the major month having 30 days and the minor month having 29 days, and its average calendar month is equal to one synodic month. Which month of the year is older and which is smaller is determined by calculation.

Common terms for the lunar calendar:

Ecliptic longitude: is used in the ecliptic coordinate system to determine the presence of celestial bodies in the celestial sphere.

The coordinates of the position on the earth are divided into 360 degrees, and in this system (celestial sphere) the earth is divided into two hemispheres by the ecliptic plane, and the sun moves to 0 degrees of ecliptic longitude for the spring equinox, 90 degrees of ecliptic longitude for the summer solstice, 180 degrees for the autumn equinox, and 270 degrees for the winter solstice.

The first day of the first month: The first day of the first month of the calendar is usually referred to as the first day of the year. In fact, strictly speaking, "year" is a dry calendar.

The original meaning of "Sui Shou" is the first day of the first month of the Tai Sui, that is, the beginning of spring. The lunar calendar is based on the phases of the moon.

The synodic change is one month, and the first day of the first month of the lunar calendar is mostly called "Yuan Shuo".

The lunar calendar is determined according to the cycle of the moon phases, each moon phase synodic change is one month, divided into leap years and peaceful years, leap years 13 months, and ordinary years 12 months. Each month has a big month and a small month. The big month is 30 days, and the small month is 29 days.

A common year in the lunar calendar has an average of 12 days in 12 months, while a leap year has one more leap month than a common year, with an average number of days.

The lunar calendar year is generally 354 days.

How many days is there in a lunar year, 366 days.

A lunar year is 354 days in a normal year and 384 days in a leap year.

1. The number of days in each month in the lunar calendar is established according to the cycle of the moon's movement, in fact, the average number of days per month is days, if multiplied by 12, there are only days in a year. And the earth revolves around the sun for one cycle (return year, solar year) is days, so the actual number of days in a lunar year is less than that of a solar year, almost 11 days, and 19 years is 209 days less.

The day divided by 30 is, that is, in 19 years, the lunar year is almost 7 months less than the solar year. In order for the lunar calendar to be not too different from the solar calendar, it is necessary to make up these 7 months.

3. China's lunar calendar is a typical lunisolar calendar, which is formulated by taking into account the movement cycle of the moon around the earth and the movement cycle of the earth around the sun, and is a calendar combining the lunar calendar and the solar calendar, in order to make up for the 7 months, people take the method of setting leap months in the lunar calendar The method of 19 years and 7 leap years is 19 years, that is, in the 19 years of the lunar calendar, 12 are ordinary years, 12 months per 1 ordinary year, plus 7 leap years, and 13 months per 1 leap year.

4. In this way, the number of days in the 19 solar years is almost equal to the number of days in the 19 lunar years, so that every 19 or 19 times the number of birthdays.

, the solar birthday and the lunar birthday have a chance to appear on the same day.

Repeat once in nineteen years.

In the lunar year, a year with a leap month is called a leap year, which is generally 12 months and 354 or 355 days, and a leap year is 13 months, 383 or 384 days. As a lunisolar calendar, the number of days in the lunar calendar is determined according to the monthly wancing, and the time of the year is based on 12 months;

In order to coincide with the Earth's orbital cycle around the Sun, i.e., the return year, one month is added every 2 to 4 years, and the additional month is a leap month, so that a leap year in the lunar calendar is 13 months.

The calculation of leap months in leap years in the lunar calendar is one leap in 3 years, two leaps in 5 years, and seven leaps in 19 years; The lunar calendar is basically a cycle of 19 years, corresponding to the same time in the Gregorian calendar. For example, May 27, 2001, May 27, 1982 and May 27, 1963 in the Gregorian calendar are all the fifth days of the fourth month of the leap month.

A lunar year is usually 354 days, and if there is a leap year, there are many more.

Generally, a lunar year is 354-355 days when there is no leap month, and if there is a leap month, it may be 384-385 days.

There are 354 days in a common year and 384 days in a leap year.

The first day is the first day of the first lunar month (i.e. the Spring Festival), and the last day is the 30th day of the lunar month (sometimes the 29th day of the lunar month) (i.e. the Chinese New Year's Eve of the next lunar year). The lunar calendar and the solar calendar are also called the lunar calendar, and the lunar year is 354 days, which is according to the moon.

One circumference around the Earth is calculated as one month. A lunar year is sometimes 12 months, sometimes 13 months, and a year with a leap month is 13 months.

The Gregorian calendar is also called the Gregorian calendar. The year of the solar calendar is 365 days, which is calculated based on the rotation of the earth around the sun as a year. It takes a little more than 365 days and 5 hours for the Earth to revolve around the Sun.

The solar calendar (365 days a year) has more than 11 days per year than the lunar calendar (354 days a year), and in order to avoid the months of the solar calendar and the lunar calendar getting bigger and bigger, leap months are used to make up for it. There are 7 leap months in 19 years. Generally, it is the beginning of spring before the Spring Festival of the lunar calendar, and there is no leap month in the second year.

The months of the year in the solar calendar are 31 days and 30 days. February is generally 28 days. February 4 has a 29-day day.

The reason why there is an extra day is because the solar calendar has more than 365 days and 5 hours a year, and there will be an extra day in almost 4 years.

As for the 29 days of February of that year, there is no remainder as long as the year of the year is divided by 4.

February of that year was 29 days. For example, in 2004, if there is no remainder in the division of 4, then February of that year must be 29 days and there is a remainder in the division of 4, and February in these three years must be 28 days.

The year of the Gregorian calendar is 365 days, which is calculated according to the rotation of the earth around the sun as a year. It takes a little more than 365 days and 5 hours for the Earth to revolve around the Sun.

One year is usually the time it takes for the Earth to revolve around the Sun, or the time interval that the Sun travels on the celestial sphere along the ecliptic from a certain punctuation point to the same punctuation point. Due to the different punctuation chosen, the definition of the year is also different, usually there are:

1 Return year (solar year) = day.

1 sidereal year = day.

1 Node Year = Day.

1 perigee year = day.

Julian years are now used in astronomy, and its exact value is 86,400 seconds per day, for a total of 31,557,600 seconds.

There are 365 days in a normal year;

Leap years have 366 days.

1. A total of 354 or 355 days in 12 months of a year.

2. Lunisolar calendar.

That is, China's lunar calendar, which promotes the length of the solar calendar to avoid the shortness of the lunar calendar, determines the "month" according to the waxing and waning cycle of the moon, and revolves around the sun with the earth.

The length of the week, i.e., a return year, is used as the average length of a year. The lunar calendar stipulates that the big month is 30 days and the small month.

29 days, a total of 354 or 355 days in 12 months of the year, about 11 days less than the return year, and more than 1 month less in 3 years.