Question

You are outside enjoying a beautiful day. the sky is bright blue. when the sun sets, the sky turns a gorgeous salmon pink. after the sun has set, the sky pales to pink, then lavender; as it gets dark, the sky becomes a deeper purple, then midnight blue, and, finally, it looks black. the color changes you perceive in the sky are due to the __________ of light that it reflects.

Answer 1

This phenomenon is due to how the different wavelengths of light are scattered by the molecules of the atmosphere. On a clear day, the sky is bright blue because the short-wavelength components of the visible spectrum (violet and blue) are scattered more, and therefore they arrive at our eyes from all directions. (But our eyes do not perceive violet very well, therefore the sky appears just blue). When the sun sets, however, the path covered by the sunlight to reach our eyes becomes longer, and then blue light is scattered away and longer wavelengths (orange-red) start to reach our eyes and this is why the sky turns into this colors. Finally, at night the sky appears black because there is no sunlight (and black is absence of colors).