Thursday, September 1, 2011

Sky 12

It was another dull day but in the evening it was glorious.

We were naughty and drove off to get a take-away from a village nearby and sat outside eating and drinking wine (my last until after the Liverpool marathon). Most enjoyable!

I love seeing the sun disappearing through the trees.

Mike tells me that the blue color of the sky is due to Rayleigh scattering. 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.

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