Why the Blue Color of the Sky Implies the Red and Green Colors of the Aurorae.

Absorption Spectrum of Oxygen



Color Photograph of the Aurora.



The sky is blue because of several reasons. The first commonly given explanation is Rayleigh scattering, which is TRUE but not complete. Blue IS scattered more tham red, which paints the sky blue. There is another partial explanation due to the spectrum of oxygen as shown in the first image above. White light, as perceived by the eye, is a mixture of the ophthalmic colors of red, green, and blue. When red and green are subtracted from white light, the resulting color is pale blue, exactly as seen in the sky.

The emission spectrum of oxygen is exactly the same as its emission spectrum. Therefore, when oxygen is activated by incoming ionizing radiation at the magnetic poles, it emits exactly the colors that are absorbed during daylight.

The images above clearly display the colors of the aurorae.