Why The Sky Is Blue

Why the sky is blue Further information: Why the sky is blue When one looks at the sky, rather than seeing the black of space, one sees light from Rayleigh scattering off the air. Rayleigh scattering is proportional to the inverse fourth power of wavelength, which means that the shorter wavelength of blue light will scatter more than the longer wavelengths of green and red light. This gives the sky a blue appearance. Conversely, when one looks towards the sun at sunset, one sees the colors that were not scattered away -- the longer wavelength, red light.