What does Yuyu in the calendar mean?

The geography in the calendar is said to refer to the calendar map made by ancient astronomers to record the laws of celestial bodies and the changes of solar terms. In this painting, there are two important buildings-one is the Sun Palace and the other is the Moon Palace. The Sun Palace refers to the track of the sun on the ecliptic, while the Moon Palace refers to the track of the moon on the ecliptic. These tracks are divided into 24 solar terms, and each solar term has its own unique name and significance.

The emergence of Yuyu makes people have a deeper understanding of astronomy and a more accurate grasp of time and space. In ancient times, people celebrated every solar term, offering sacrifices to the gods with some ceremonies and thanking heaven and earth for their kindness. This tradition continues to this day. Every year, traditional festivals such as Spring Festival, Tomb-Sweeping Day, Dragon Boat Festival and Mid-Autumn Festival are determined according to the solar terms.

Although the jade in the calendar is not very common in our modern life, it does carry a part of human civilization. It lets us know the position and trajectory of the south and north celestial poles, as well as the motion laws of the sun, the moon, the five planets and Uranus. This knowledge also helps us to explore the universe and distant galaxies, because they all follow the laws of everything in the universe.