The phenomenon responsible for the scattering of light in the atmosphere is known as Rayleigh scattering. This scattering occurs when light rays interact with small particles or molecules in the air. Shorter wavelengths of light, such as blue, are scattered more than longer wavelengths, like red. This is why the sky appears blue during the day. Rayleigh scattering also contributes to the color changes observed during sunrise and sunset when the sunlight passes through a thicker layer of atmosphere and the blues are scattered out, leaving reds and oranges visible.