What is the calendar, there are several types, calculated?

Calendar Terms - Calendar comes from Latin Calendarium, originating from the ancient Roman word, meaning Debt Book. The debtors have to pay the debtors interest at the beginning of the month, gradually get used to them, become the calendar, to measure the time period.

There are many types of calendars, the solar calendar, the Lunar calendar . Each calendar type has its own history and characteristics. The most commonly used calendar in the world today is the Roman calendar, which is known as the solar calendar, based on the Sun, which has been modified many times quite uniformly.

The type of lunar calendar we are using is actually combining the negative - the solar, the moon and the sun, the month according to the Moon, but the Sun or the Earth's position in orbit. In both main calendar types, a special base is found: Base 12.

In the solar calendar, it is considered to be the first year - the first year Jesus was born. However, it formed a long time before Jesus was born, and was recalculated as the first year after Christianity ruled Rome, that is, long after Jesus was born.

Historically, Jesus was not born in the first year of AD, but around 8-4 BC at Betlehem, crucified on the cross? Gongothar about 29-33 AD. Therefore, the first year of AD is entirely relative. According to the calendar calculation, there is no zero. It means that after the first year of BC is the first year of Christ.

The solar calendar is calculated so that the nearest year on the calendar compared to an Earth circle orbiting the Sun is 365,24220 days. One day is 24 hours.

A round of Earth in orbit is not equal to an even number of days. Therefore, a year needs 365 days, but odd numbers need to be supplemented in some way. The odd number 0.2422 can be described by an approximate simple fraction of 1/4; 7/29; 8/33; 31/128; 132/545; . that means to approximate the installation, 4 years need to add one day, more accurately, 29 years need 7 more days, more 33 years for 8 days . Benefit is 97/400. The calendar we currently use has a relatively complicated rule. That is: every 4 years, one more day: all the years divided by 4 liabilities a day.

But: For every hundred years, one day must be reduced: the year is divided by 100 for no profit. For every 400 years, one more day is needed: the year is divided by 400 for profit. For every 4,000 years, one day will be reduced: the year is divisible by 4,000 will not be profitable.

So 1800, 1900 was not profitable, but in 2000, it was just a profit.

In fact, the above fraction is not absolutely accurate. If it is true, it must be added: the year divided by 20,000 will be two days' profit, then we have a fraction (969x5-1) /20,000 = 4844 / 20,000 = 0.2422, more closely than the reality. However, waiting up to 20,000 years, there must be too many changes at that time.

Calendar calculation map of Mayan people

Nguyen Hien Nhan