How many days are there in a year?

The Gregorian calendar, which is popular in the world today, is a kind of solar calendar, with 365 days in a normal year and 366 days in a leap year, with a leap every four years. ? The earliest source of the Gregorian calendar can be traced back to the solar calendar in ancient Egypt. The Nile is the lifeblood of Egypt, and it is precisely because of the need to calculate the flood cycle of the Nile that the astronomy and solar calendar of ancient Egypt came into being. Maya civilization is an outstanding representative of ancient Indian civilization in Central America and ancient Indian civilization in America, named after Indian Maya. Mainly distributed in southern Mexico, Guatemala, Brazil, Belize and western Honduras and El Salvador. It was formed in about 25 BC, and an early slave country was established around 4 BC. It flourished in the 3rd to 9th centuries, declined in the 15th century, and was finally destroyed by Spanish colonists, and then disappeared into the tropical jungle for a long time. :

the lunar calendar, also known as the summer calendar, the lunar calendar, the old calendar, the Han calendar and the old calendar, is one of the traditional calendars in China, and the lunar calendar belongs to the yin and yang calendar. Gregorian calendar: A solar year is the time between two beginning of spring, about 365.2422 days. The lunar calendar is calculated according to the fact that the moon revolves around the earth for one month. The year of the lunar calendar is sometimes 12 months and sometimes 13 months. The year with leap month is 13 months.

Gregorian calendar. A year in the Gregorian calendar is 365 days, which is calculated according to the fact that the earth revolves around the sun once a year. The time for the earth to go around the sun is 365 days and a little over 5 hours.

The lunar calendar in the lunar calendar takes the month as the basic unit, and a month begins with the day when the new moon appears and ends the day before the next new moon appears. Because the period of the moon's revolution is between 29 and 3 days, a month of the lunar calendar is also 29 or 3 days from the time when the new moon appears. The big moon is 3 days and the small moon is 29 days. Different from the solar calendar, big and small months are not fixed in different years. For example, the day before the Spring Festival is often called New Year's Eve, but there are many years when the lunar calendar has only 29 days in December. Because the twelve-month period is about 11 days shorter than the solar year, that is, the time for the earth to revolve around the sun, in order to keep the lunar year and the solar year relatively stable, a leap month needs to be added every two or three years. About every nineteen years, seven leap months will be added. The twenty-four solar terms are determined by the position of the earth in the orbit around the sun. Starting with the annual winter solstice, every 15 degrees is a solar term. Therefore, the 24 solar terms have roughly fixed dates in each month of the Gregorian calendar. In ancient times, 24 solar terms were used to guide farming, which is the source of the title of the lunar calendar. Among them, the twelve solar terms in the second half of the solar calendar are also called Zhongqi. There is a direct relationship between the time when the gas appears and the determination of leap month.

Reference: Baidu Encyclopedia _ One Year Baidu Encyclopedia _ Calendar