What color is the blue sky in Wan Li?

This sentence has been pointed out. Because the sky is blue, it must be blue. Color has three characteristics, namely hue, lightness and saturation. The wavelength and intensity of electromagnetic waves vary greatly. In the wavelength range that people can feel, it is called visible light, and sometimes it is simply called light.

Academic language of sky and space. In space science, the sky is divided into two parts, namely "the sky" and "the sky". Cosmic space, also known as outer space, outer space for short, refers to the void area outside the earth's atmosphere, which is usually distinguished from airspace (territory) by outer space.