According to the Gregorian calendar, are there leap years?

Why do Gregorian calendar have leap years and lunar calendar have leap months?

The farming season in agriculture is based on the Gregorian calendar and the Lunar calendar, which are widely used in China. The Gregorian calendar has 365 days in a year and 366 days in a leap year, because there are only 28 days in February of a normal year and 29 days in February of a leap year. There are only 354 or 355 days in the lunar calendar year; There are 384 or 385 days in leap month every year. Because the lunar calendar generally has only 29 or 30 days per month, every year there is a leap month, which means one more month.

Why do Gregorian calendar have leap years and lunar calendar have leap months?

The Gregorian calendar, which is widely used in the world today, was adapted from julian calendar, Rome. Astronomically speaking, the time for the earth to return to vernal equinox from vernal equinox once around the sun is called a tropical year, which is very long.

Year) is 365 days, and there is a leap year of 366 days every four years. By 325 AD, julian calendar was adopted by Christian countries at that time, and the vernal equinox of this year was March 2 1. Because the average calendar year in julian calendar is 0.0078 solar days older than that in Uni-President (that is, the average annual length is about 1 1 minute and 14 second), it has accumulated to 1582 from 325 AD, with a difference of ten days. Therefore, the vernal equinox on March 2 1 day was advanced to March 65438. In order to avoid these mistakes, the date of October of 1582 15 is specified as 1582 15. The method of setting leap years is also clearly defined: according to the Gregorian calendar era, any year that can be divisible by 4 is a leap year; But in every hundred years, it is not a leap year divisible by 4, but a leap year divisible by 400. For example, 1968 is a leap year, and 1900 is a hundred years. It is divisible by 4 but not by 400, so it is not a leap year, and 2000 will be a leap year. In leap years, one day is added in February, and the whole year is 366 days.

The lunar calendar (also known as the summer calendar), which is still in use, is characterized by paying attention to the changes in the profit and loss of the moon phase and taking care of the cold and summer solar terms. It stipulates the 30th day of the big moon and the 29th day of the small moon, because the time of the moon's phase change for one week (called the new moon in astronomy) is 29.5306. In this way, the average value of several months is similar to the length of "Shuowangyue". Therefore, the normal year has 65,438+02 months, and the whole year has only 354 or 355 days, which is about 65,438+00 days and 265,438+0 hours away from the tropical year. In order to correct this mistake, it is stipulated to add one leap month every three years, two leap months in five years and seven leap months in nineteen years, so as to merge the years; In this way, the lunar leap year has a total of 13 months, and there are 384 or 385 days in the whole year. Through this ingenious arrangement, the solar terms represented by each month are not much different, but the leap month in the lunar calendar is not always stipulated in February like the Gregorian calendar; There are also solar terms, which are not as fixed as the Gregorian calendar, and its calculation is more complicated. The number of days in a normal year differs from that in a leap year by many days, so it is more common and convenient to adopt the solar calendar than the lunar calendar. However, if we look up the book Calendar, we can clearly know which year is a leap year and which month is a leap year.