What is the explanation of the stars?

A huge sphere consisting mainly of hydrogen, helium and a small amount of heavier elements.

On a sunny night, there are always countless light spots embedded in the night. Except for a few planets, most of them are stars. The sun is the closest star to the earth, and almost all the stars that can be seen at night are in the Milky Way. The Milky Way has about 300 billion stars, and humans can only observe a small part. ?

Humans have been observing stars for a long time, and there are various observation methods. Those brighter stars are divided into constellations and clusters, and some stars have their own names. The brightness of a star is called magnitude, and the brighter the star, the lower the magnitude. Astronomers have also compiled a catalogue to facilitate research.

The ancients' explanation is:

In ancient people's minds, there should be a country and society like the earth, so they compared the situation on the earth and gave the stars in the sky corresponding to the things on the earth: the son of heaven, the princes, the army and so on. It is also mixed with many mythical elements. In the northern sky, the stars can be divided into three walls: Wei Zi wall near the northern celestial pole, Taiwei wall in the eastern sky and Shi Tian wall in the northern sky.

There are many stars on every wall, which share different "positions" according to the imagination of the ancients: Ziwei Garden is where the emperor lives, Taiwei Garden is where the emperor handles government affairs, and Tianshi Garden is where transactions are conducted. Every wall has things or officials made up of various stars.