Tuesday, April 10, 2012 6:17:32 PM
There are as many colours in a rainbow as anyone wants to decide there are, at least up to about 400,000,000,000,000 (the visible light spectrum is about 4x10^14 Hz wide).
Humans often put things into discrete groups when in reality they are a spectrum. Including, but not limited to, the colours in a rainbow.
Tuesday, April 10, 2012 4:00:56 PM
It's a complete rainbow, coolthing97. There are only six colors in the rainbow. Newton had real OCD and had an obsession with the number seven, so he "found" indigo in between blue and violet.