People say that the sky is the roof of the earth. When standing on the surface of the vast earth, we look up at the sky, of course, it looks like a natural phenomenon like smoke that has various forms of various colors, that scene is the beginning of a dazzling sky, but some say it is a beautiful phenomenon. Based on that background, experts say that, the sky is the top of the earth's surface, and is classified as a separate layer called the atmosphere.  The sky consists of a lot of gas and air, with different compositions in each layer. The sky often looks blue when morning or evening, because the air refracts blue light from sunlight more than red light. The sky can change color under certain conditions, such as red at dusk or black when it rains. The sky that is so beautiful can make anyone who looks into fascination.  When you look up at the sky, what is often seen is blue. And the question arises from the situation why is the sky blue? Answers like this also invite experts to explain, as some say it happens because the sun is in the sky and light passes through the atomosphere, blue light is scattered in all directions. Blue light is scattered in all directions by small molecules of air in the Earth's atmosphere.  Blue is more scattered than other colors because the wavelength is smaller. In addition, light is also reflected and spread by the surface of the earth. All of this scattering is mixed and therefore we see the blue sky. Now that's the answer that is often found among scientists about the question above. Hopefully what has been conveyed is useful. Thank you very much.