It is said that eating moon cakes in Mid-Autumn Festival began in Yuan Dynasty. At that time, the broad masses of people in the Central Plains could not bear the cruel rule of the ruling class in the Yuan Dynasty and rebelled against the Yuan Dynasty. Zhu Yuanzhang joined forces with various resistance forces to prepare for the uprising.

However, the officers and men of the imperial court searched very closely and it was very difficult to pass on the news. Strategist Liu Bowen came up with a plan and ordered his subordinates to hide the note containing the "August 15th night uprising" into the cake, and then sent someone to send it to the uprising troops in various places separately to inform them to respond to the uprising on August 15th night. On the day of the uprising, all the rebels responded together, such as single spark can start a prairie fire.

Soon, Xu Da captured the Yuan Dynasty and the uprising was successful. When the news came, Zhu Yuanzhang was so happy that he quickly gave a message that all the soldiers would have fun with the people in the upcoming Mid-Autumn Festival, and he would give the "moon cakes" that were sent in secret when he started fighting that year as seasonal cakes to his ministers.

Since then, the production of "moon cakes" has become more and more elaborate, with more varieties, such as discs, and has become a good gift. After the Mid-Autumn Festival, the custom of eating moon cakes spread among the people.

2. The part of the moon that is irradiated by the sun is bright, and the part that is not irradiated is dark. Although the moon is half a sphere every time it is illuminated by the sun, the positions of the sun, the earth and the moon are changing every day, so sometimes the moon faces the earth with its completely bright side, and sometimes it faces the earth with its side. In this way, the moon shows the change of rain or shine.

Extended data

There are a large number of huge impact craters filled with basalt lava flows from dark volcanoes on the front of the moon, forming a vast plain called "Moon Sea". In fact, there is not a drop of water in the "Moon Sea". There are bright and ancient plagioclase highlands and obvious impact craters between the periphery of the Moon Sea and the Moon Sea.

It is the brightest celestial body except the sun in the sky. Although it is very bright white, its surface is actually very dark, and its reflectivity is only slightly higher than that of old asphalt. Because the moon is very conspicuous in the sky, coupled with the regular moon phase changes, it has had a great influence on human culture such as myths and legends, religious beliefs, philosophical thoughts, calendar compilation, literature and art, customs and traditions since ancient times.

The rotation of the moon is equal to the period of revolution (called tidal locking), so the moon always faces the earth in the same direction. The earth's ocean tides are mainly caused by the gravity of the moon.

Because the tidal force of the earth's ocean is opposite to the direction of the earth's rotation, the earth's rotation is always "braked" by an extremely weak force, which has accumulated for a long time. There is sufficient evidence that the earth's rotation cycle is getting slower and slower, and the time of a day is growing very slowly, increasing by 1 second in a few years.

Due to the earth's reaction, the moon is slowly getting farther and farther away from the earth, about 3.8 cm away from the earth every year. The ratio of the size of the moon to the sun is close to the ratio of the distance, which makes its apparent size almost the same as that of the sun. During the solar eclipse, the moon can completely cover the sun and form a total solar eclipse.