1. The blue color of the sky is due to Rayleigh scattering, a phenomenon that occurs when the size of the particles is much smaller than the wavelength of the incident light. As sunlight passes through the atmosphere, the shorter-wavelength blue and violet light is scattered more extensively, which is why the sky is typically blue.2. Clouds appear white because of Mie scattering, which happens when the size of the particles in the cloud matches the wavelength of the incident light. This scattering effect enhances the light of all colors, resulting in the white appearance of clouds.3. The reddish color of the sky at sunset is caused by the fact that as sunlight travels through the atmosphere, the blue and green light is scattered away extensively, while the longer-wavelength red and orange light is less scattered and thus dominates the sky's color. Clouds反射 sunlight, thus they also appear red at sunset.4. On the moon, there is no atmosphere to scatter the light, so the sky remains black even during the day. This is because there is no scattering of light by the atmosphere to change its direction.5. Mie scattering, proposed by the German physicist Gustav Mie in 1908, describes the behavior of light scattering when the particle size is similar to the wavelength of the incident light. This scattering mechanism is widely observed in nature, such as in fog, smoke, raindrops, and the atmospheres of planets.