Nitrogen and oxygen molecules contribute to the scattering of sunlight in Earth’s atmosphere, leading to the blue colour of the sky.
Nitrogen molecules are tiny and contain a large number of electrons, making them strong blue light scatterers. When sunlight reaches the atmosphere, nitrogen molecules scatter shorter blue wavelengths more than longer wavelengths, which contributes greatly to the sky’s blue colour.
Although oxygen molecules are larger than nitrogen molecules, their electron arrangement allows them to effectively deflect blue light. Oxygen increases the scattering of blue light, which intensifies the sky’s blue colour.