In the horizon theory, how to explain the rising and setting of the sun?

There were three theories of the universe in ancient China, namely, Gaitian theory, Huntian theory and Michelle Ye theory, but there was no so-called "horizon theory", which was probably invented by the subject himself. Among these three theories, Zhang Heng's Huntian Theory (Huntian Instrument) in the Eastern Han Dynasty is the most famous. Huntian said that eggs are used to describe the sky, the ground is as yellow as eggs, and the sky wraps the ground, just like eggshells wrap egg yolks. The sky is full of water, supported by air, and the earth floats on the water.

In summer solstice, the sun runs to the northernmost part of the ecliptic; In winter solstice, the sun runs to the southernmost tip of the ecliptic; The rising and falling position of the sun in different seasons represents the length of day and night, which can be clearly seen from the armillary sphere. Huntian theory is a long-term dominant view of the universe in ancient China.

We can judge our position according to the sun.

We all know that the sun rises in the east and sets in the west, but we should pay attention. In fact, most of the time, the sun does not rise in the east, but sets in the west.

The track of the sun, in our summer, the sun rises in the northeast and sets in the northwest; In our winter, the sun rises in the southeast and sets in the southwest; The sun only rises and sets at the vernal equinox and autumnal equinox.

What are the vernal equinox and autumnal equinox? As we all know, the days are short and the nights are long in winter, while the vernal equinox and autumnal equinox are just as long as day and night, which are around March 2 1 and September 23, respectively.

Of course, when there is no sun at night, we can also judge our position by Polaris. Most people regard the earth as a reference object and stand still, and they will feel that the sun rises in the east and sets in the west. In fact: the earth rotates and the sun does not move. When you watch the sunrise in the morning, just stare at the sun. When it is not moving, take it as a reference. Watch it carefully. Then you feel the earth turn from west to east.