Yesterday I heard an otherwise affable and informative physicist at Ottawa University say there were only SIX colors in the rainbow. That seven is just the social need for that number.
He wasn’t counting indigo.
What do you think?
Miriam's Well: Poetry, Land Art, and Beyond
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Miriam's Well: Poetry, Land Art, and Beyond 
Not my rainbow he’s talking about!
I’ll bet he only has nine fingers, not ten?
The physics is quite clear: 7 colors in the visible spectrum –
https://www.physicsclassroom.com/class/refrn/Lesson-4/Rainbow-Formation
Perhaps he is 1/7 colorblind?
I am deeply and personally offended
I’ve assumed that a rainbow includes an infinite number of color frequencies and that people (and, perhaps, cultures) differ as to how many colors their brains distinguish.
Correct as usual, Mr. Peabody.
Say it ain’t so!
First Pluto and now indigo? Next they’ll tell us that Heinz doesn’t have “57 varieties”. LOL — where will it all end?! :- D
(I’ve since discovered that 57 was a number entirely contrived for advertising purposes. ::sigh:: The sadness of knowledge!- )