Why is the sky blue?

Light from the Sun (white light) is made up of many colours - red, green, blue, 
and so on. Each of these colours has a different wavelength and frequency. When 
light reaches the atmosphere it hits gas molecules which scatter the light in 
all directions. This scattering is called Rayleigh scattering after Lord 
Rayleigh who worked out the mathematical equations to describe it. 

So how does Rayleigh scattering work? Rayleigh scattering only happens when the 
molecules of gas encountered by the light waves are small compared to the 
wavelength of the light. What’s strange about Rayleigh scattering is that not 
all of the light is scattered evenly. Some wavelengths are scattered more. With 
white light, mostly the light of shorter wavelengths (the blue end of the 
visible range) is scattered whilst the longer wavelengths (the red end) are 
mostly uneffected. This means the blue light is scattered more than the red. 

But violet light has the shortest wavelength so why isn’t the sky violet? Well 
it’s true that the violet light is scattered more than the blue light, but our 
eyes aren’t so good at picking up violet light. This means we see the sky as 
being blue even though there is some violet light there too.

The above information was taken from these sources:

(http://www.sciencenet.org.uk/database/Physics/Original/p00125d.html)
and,
(http://groups.google.com/groups?q=why+is+sky+blue%
3F&hl=en&selm=33C461D4.24E0B9%40flash.net&rnum=9)

And another web site touching on the phenomena is the eponymous
<a  href="http://www.why-is-the-sky-blue.org/">http://www.why-is-the-sky-
blue.org/</a>.

http://www.sciencemadesimple.com/sky_blue.html is another reference.
Also, congratulations on posting the very first GA question - a piece
of net history!

shocking I know, but I couldn't stop myself from posting a comment to
the ID2 question - my personal stake for perpetuity...!

Whoo hoo! Almost first post! <haha.. only funny if you read /.>

Couldn't resist.. SORRY!

Yes ... But what ever happened to Birdie?

He/she failed to rate the Answer; he/she never asked another Question;
he/she is the only user to my knowledge who has never had a GA behind
his/her handle.

There is more to this than meets the eye which makes me wonder ...

Is the Sky really Blue?

Well, ...

http://answers.google.com/answers/threadview?id=38097

I'd think that if anyone would know why the sky is blue, a birdie would know.

You are absolutely right, Pink!

Why would a Birdie ask such a question in the first place?

Curiouser and curiouser ...

Yes, Freddy ... But that was Birdie-GA, and this is Birdie zonder GA.

Well spotted all the smae!

Ah, finally found it!

The question I mean - not birdie, sorry :-)