Why is the sky blue?
White sunlight is really a lot of different colors of light mixed together. Some colors of light travel through air and dust better than others. Red goes a long, long way. But blue light gets bounced around a lot. Our blue sky is blue light that has been bounced out of sunlight by gazillions of molecules of air. – Answer Provided by Bonus.
The Short Answer. The molecules which make up 99% of the earth’s atmosphere do not absorb any wavelengths of visible light. Molecules in the air are not like indigo molecules which absorb red light and give blue cloth its color. Molecules in the air are not pigments. However, molecules in the air do scatter blue light more strongly than red light. This means that white sunlight has its blue components scattered to the side while its red components keep traveling straight. White sunlight bathes the atmosphere of the earth. The sky is blue because molecules in the air scatter blue to your eyes more than they scatter red. But Why? But why do molecules in the atmosphere scatter blue light more than red? The oxygen, nitrogen, and water molecules plus the argon atoms that make up most of the air do absorb ultraviolet light, in the region of the spectrum known as UV-C. (It is a good thing they do too, these dangerous germicidal UV wavelengths from the sun are stopped by the atmosphere before
POSTED 17 SEP 1998. Each “color” of light is a different wavelength of electromagnetic radiation, and sunlight contains every color of the rainbow. Wavelength doesn’t just control color, but also other behavior of radiation. Thus short-wavelength X-rays can pass through our bodies much better than longer wavelength visible light. Similarly, the various wavelengths of visible light interact differently with molecules in the air. When sunlight strikes these molecules, they scatter — bounce — blue rays more than red rays. Since the blue portion is scattered until it seems to come from all directions of the sky, the sky looks blue. Did you know? When the sun is low on the horizon, its light must pass more air molecules to reach us than when it’s higher in the sky. Because more blue light is scattered, the light coming directly from the sun has a higher proportion of red wavelengths. That’s why the sun looks so red at dawn and dusk.
