Some debate exists over whether indigo is distinct from blue and violet on the color spectrum.
Some debate exists over whether indigo is distinct from blue and violet on the color spectrum.
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The reason for the "seven" colors is that when they were named from the results of the spectrum thrown by a [[prism]], seven was considered to be a holy number, dating to the seven observable (non-[[star]]) objects in the heavens (the sun, the moon, and the five planets visible to the naked eye).
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The reason for the "seven" colors is that when they were named from the results of the spectrum thrown by a [[prism]], seven was considered to be a holy number, dating to the seven observable objects (excluding distant stars) in the heavens (the sun, the moon, and the five planets visible to the naked eye).