Why sky is blue in color? Physics Q&A (2024)

The phenomenon of scattering of light helps to explain the blue color of sky

1. Scattering of light takes place when size of the scattering object (such as air molecules) is very very small as compared to wavelength of light
2. According to Rayleigh's law of scattering, the amount of scattering is inversely proportional to $\lambda$⁴.
3. Thus when light from sun travels through earth's atmosphere, the different wavelengths get scattered from their path through different amounts obeying Rayleigh's law of scattering.
4. Since wavelength of blue color is approximately half the wavelength of red color, the scattering of blue light is about 2⁴ times more than red light.
5. Due to this blue color predominates and the sky appears blue.

See Also

Red Sky at Night ... Any Truth To It?What colour is space?Looking at the skyWhy Are Clouds White, And Why Is The Sky Blue?