by Phate on Mon Jul 03, 2006 11:59 am
why is the sky blue?
When the sun's rays hit the Earth's atmosphere some are absorbed by the gas molecules. After a while the molecule radiates the light back out in a different direction.
Different colours of light (that make up the visible spectrum) are affected differently but the higher frequency end (blues) get absorbed more frequently than the lower frequency reds.
As light moves through the atmosphere, most of the longer wavelengths pass straight through. Little of the red, orange and yellow light is affected by the air.
However, much of the shorter wavelength light is absorbed by the gas molecules. The absorbed blue light is then radiated in different directions. It gets scattered all around the sky. Whichever direction you look, some of this scattered blue light reaches you. Since you see the blue light from everywhere overhead, the sky looks blue.