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Why isn't the sky violet, Daddy?

Kids often ask why the sky is blue. While physics textbooks correctly explain that short wavelengths of sunlight, such as the ones that we see as blue, more readily ricochet off atmospheric gas molecules into our eyes than do other solar wavelengths, that's only a partial answer, says electrical engineer Glenn S. Smith of the Georgia Institute of Technology in Atlanta.

In fact, the measured spectrum of sunlight that makes it to our eyes after scattering off nitrogen and oxygen molecules remains roughly as intense at violet wavelengths as it does at blue ones, he notes.

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