Bidding farewell to 2023, we enter the exciting year 2024. According to astronomical science experts, 2024 in the Gregorian calendar is a leap year, with 29 days in February, with a total of 366 days in the year, while the upcoming Jiachen year (Year of the Dragon) in the lunar calendar is a common year, with a total of 354 days in the year. Why is this?
Yang Jing, a member of the Chinese Astronomical Society and a director of the Tianjin Astronomical Society, explained that the current internationally used Gregorian calendar, commonly known as the "solar calendar" in mainland folklore, is formulated according to the movement cycle of the earth around the sun, that is, a return year. The length of a return year is 365.2422 days, i.e. 365 days, 5 hours, 48 minutes and 46 seconds.
Since the return year is not an integer, it is stipulated that the Gregorian calendar has one leap year every 4 years. Leap years are intercalary years with 29 days in February, 366 days in the year, and year with 28 days in February, 365 days in the year. The year 2024 can be divided by 4, so it is a leap year. However, if it is a whole century year (e.g. 1800, 1900, 2100), it can be divisible by 100 but not divisible by 400, and it is still a common year.
The lunar calendar is the traditional calendar of the mainland, and its arrangement of the year, month and solar terms is based on the two natural cycles of the moon phase and the annual apparent movement of the sun.
The lunar calendar is monthized according to the synodic changes of the moon, and there are 12 months in the year, with 30 days in the major month and 29 days in the minor month, and 354 or 355 days in the year, which is 10 to 12 days less than the 365 or 366 days in the Gregorian calendar year (also known as the return year).
In order to adjust the time difference between the 12 synodic months and one return year, the ancient people in the mainland adopted the method of setting "leap months". The current method of "intercalation" in the lunar calendar is "seven intercalary months in 19 years", that is, one month is added every 2 to 3 years, and the additional month is called "leap month". A year with a leap month is called a leap year, which contains 13 lunar months and is 384 or 385 days long, while a year without a leap month is called a common year.
Yang Jing said that the rules of "intercalation" are based on the 24 solar terms. The lunar calendar uses the 12 Zhongqi as the signs of the 12 months, that is, each month has a Zhongqi. If there is no mid-air in a lunar month, the month is called the "leap month" of the previous month.
The upcoming Jiachen year of the lunar calendar does not have a leap month, so it is a common year, and its corresponding Gregorian calendar date is February 10, 2024 to January 28, 2025, for a total of 354 days.
来源 | 新华社，转自微言教育