蓋gai，sky. Chinese English reading is the same. Perhaps the thoughts of ancient people were about the same.
The satellites outside the Earth, the ionosphere of the atmosphere, the stratosphere, etc. together constitute the structure that we look forward to.
Gaitian said that it was an ancient Chinese cosmology. Days, ancient China called the cover. The sky is like a cover, places like chess.
Northern Song folk songs:
Mullegawa, under the cloudy mountains, the sky is like a dragonfly, covering four fields. The sky is dark and wild, and the wind blows the grass and sees the cattle and sheep.