The next time it is foggy go out and see if you can spot a fogbow, the rainbows ghostly cousin. They are also know as white or ghost rainbows as they only have a red outer and a bluish inner edge.
In a fogbow the size of the water droplets are very much smaller than they are in a rainbow. More light is scattered than refracted which essentially smears out the the rainbow colours. This creates the appearance of a fatter and less sharply defined bow of white light.
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