What are the big moon and the small moon?

There are seven big months and five small months in a year. Abortion is in February, April, June and September,11; The big months are 65438+ 10, March, May, July, August, 65438+ 10 and 65438+February respectively.

According to the rotation of the earth, people have formed the concept of day by day. According to the concept that the moon revolves around the earth to produce a new moon and form the moon, and according to the alternation of seasons caused by the revolution of the earth around the sun, the concept of year is formed.

The material movements on which these three concepts are based are independent of each other. According to accurate measurement, the time for the earth to circle the sun is about 365.2422 flat solar days, which is called the tropic year. The time interval from a new moon to the next consecutive appearance is 29.5306 flat solar days, which is called the new moon.

Taking the tropical year as the unit, how many integer months are arranged in a year, how many integer days are arranged in a month, and how to choose the starting point of a year are all called calendars. The complexity of the calendar problem lies in that the two cycles of the Tropic of Cancer and the new moon are too fragmented, and their relationship on the same day is not as simple as that of kilometers and meters; Besides, they can't communicate with each other. Therefore, calendars always pay attention to one thing and lose sight of another, and it is impossible to coordinate two cycles at the same time. For these two reasons, calendars are generally divided into three categories; Lunar calendar, solar calendar, lunar calendar. The solar calendar, which focuses on coordinating the relationship between Wang Shuo and the calendar, is referred to as the solar calendar for short; The lunar calendar, which takes the moon, tropic year, calendar month and calendar year into account, is called the yin-yang calendar.