White Rainbow
November 30, 2005
Provided by: Wojtek Rychlik, Pikes Peak Photo
Summary authors & editors: Jim Foster; Wojtek Rychlik
Shown above is a classic example of a fogbow or white rainbow. This photo was taken on October 22, 2005, near Wilkerson Pass, Colorado. Though the sky above is bright blue, close to the ground, a layer of fog is evident. You might notice that this pallid beauty is a bit wider than a conventional (colored) rainbow. The droplets are also smaller in fogbows than in rainbows, and as a result, wave interference causes an overlap between light rays having different wavelengths. In essence, these fine droplets (about 0.050 mm in diameter or 1/10 the size of raindrops), are simply too small to markedly reflect and refract sunlight, and thus diffraction is dominant scattering mechanism.
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