Why is the sky blue?

[anthrax]

In winter we have very crisp blue skies

In summer (it's already true now) the sky is blueish-whitish

What's the difference?

 

[Scotsman]

A lot of it is to do with humidity. Typically there is less in the winter hence the clearer crisper looking sky. In summer you have more due to warmer air and geft more refraction of the inbound light.

Cheers,
Scotsman

 

[blut wump]

Take a Google on Rayleigh scattering

 

[anthrax]

What about temperature?

Looks like the hotter the more this "white hue"

Is it because higher temperature => higher humidity
or higher temperature => lower density
..

 

[_n8o_]

it was my understanding that the sky wasn't in fact blue that was an illusion, the sky is black and its just the way our brain sees the reflection of light, this is just what i thought happened and i am also curious as to why the sky is blue

 

[tdringo]

A clear cloudless day-time sky is blue because molecules in the air scatter blue light from the sun more than they scatter red light. When we look towards the sun at sunset, we see red and orange colours because the blue light has been scattered out and away from the line of sight.

 

[jokerswild]

blue is the dominant color in the spectrum...

 

[John C Calhoun]

The intensity of scattered light is proportional to the frequency of light raised to the fourth power: I~ v^4. Since the blue portion of the visible spectrum has the highest frequency as compared to the others (e.g. red, green, etc) the intensity of its scattered photons are greatest in the atmosphere. Actually the violet portion, which is higher in frequency (shorter wavelength) has even greater intensity; however, the human eye is more sensitive to light with blue frequencies and thus the sky looks blue to us.

 

[greenlantern11b]

wow... no ones said "Because God loves the Infantry" lol

 

[NaturalDetroit]

The sky is blue because the molecules in the air scatter light in the higher wavelengths (that is, the blue light), while lower wavelength light (that is, the light on the red end of the spectrum) goes through to the ground. So the light that get finally reflected down from the scattering is blue, therefore a blue sky.