Why does the solar calendar have 365 days in a year?

The solar calendar has 365 days a year, which was put forward by the ancient Egyptians 7000 years ago.

The month and date of the solar calendar are very consistent with the position of the sun on the ecliptic. According to the date of the solar calendar, we can clearly see the changes of cold and warm seasons in a year. But every month, you can't see the new moon, the new moon, the new moon.

At present, the Gregorian calendar, which is commonly used in the world, is a solar calendar, with 365 days in a normal year and 366 days in a leap year, once every four years, once in a hundred years and once again in the 400th year, that is, there are 97 leap years every 400 years. The average length of the Gregorian calendar is only 26 seconds away from the tropic year, and it takes only one day to accumulate 3300 years.

Extended data

The earliest source of Gregorian calendar can be traced back to the Gregorian 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 astronomy and solar calendar in ancient Egypt came into being. Seven thousand years ago, they observed the day after Sirius first rose at the same time as the sun.

In another 50 or 60 days, the Nile began to flood, so they took this day as the beginning of the year and calculated that it was 19 July. The first year was set at 360 days, and later it was changed to 365 days. This is the first solar calendar in the world.

Later, according to the situation of Nile flooding and agricultural production, they divided the year into three seasons, called flood season, winter and summer. Four months per quarter, 30 days per month, 10 days per week, five days per week. The whole year 12 months, plus five days at the end of the year, is the year-end sacrifice day.

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