why is the sky so blue?

There exists a phenomenon called Rayleigh scattering, where particulate matter blocks some wavelengths of light and helps along ("scatters") others.

Longer, redder wavelengths of light are reflected off the atmosphere, and only shorter, bluer wavelengths get through.

This is why ultraviolet light (shorter wavelength than blue) gets to the ground, but virtually no infrared light (longer wavelength than red) does.

Generally speaking, the shorter the wavelength, the more likely it is to make it through the atmosphere.

Light from the sun comes in all wavelengths, but all the radiation except blue is filtered out.

The answer I heard when I was a kid was that the sky reflects the blue of the oceans. When I asked why the oceans were blue , they said they were reflecting the sky????????????

Really, it has to do with the combination of gases in the atmosphere that sublty filter the sunlight, favoring the blue end of the spectrum. Dust and moisture particles help disperse the colour.

Thew sky on Mars is purple, reflecting the different composition, and thinner nature of the atmosphere

Light is made up of 7 colors. They are VIBGYOR. That is violet, indigo,blue,green, yellow, orange,red. The refractive index of blue is much less than the other colors of the light. So it is refracted easily by the particles present in the atmosphere. Thus the sky appears blue.

the light from the sun consists of seven colors i.e.VIBGYOR when the light enters our atmosphere blue gets dispersed most.so the sky is blue in the mornings but in the evening as the earth rotates to the east the color orange gets most dispersed most.so the evenings are orange in color

Watch this video by the scientists at Caltech:

http://coolcosmos.ipac.caltech.edu/cosmic_classroo...

this will give you the answer

http://math.ucr.edu/home/baez/physics/General/Blue...