Why the seven colors of the rainbow? What would happen if more or less than this?

The seven colors of the rainbow - do you believe that? Have you ever counted yourself? I can't catch more than four.

Look at this-

Picture - This is what it looks like when you zoom in on the real rainbow. I got the picture from English Quora. Steve Baker's answer to Why can we not see all seven colors in a rainbow during rain?

Clear purple is never seen. It is not clear whether the red is red or orange. Where are the yellow and orange? Is it possible to differentiate between blue and blue here?

Rainbow but forever. But then why come back to the 8 colors?

In fact, the great scientist Sir Isaac Newton made a more clear rainbow (meaning spectral analysis) with a glass prism. It's like this-

Photo source - Prism | optics

Here, too, roughly six colors are fairly understandable. Newton saw the same thing. But most likely, he named the seven colors of the rainbow because of a particular weakness towards the number seven. In this case, he divided Neel into Akashi and Neel. Since then, our textbook has been written in seven colors.

But is it possible to write down all the colors of a spectrum with such a precise number? No, it doesn't. Then it can no longer be called spectrum.

In fact, all the colors we see on the earth exist in the light of the sun. Depending on which one object will absorb and which one will reflect / scatter, we will know what color it is. However, the effect of many other things here is more or less the intensity of color.

And since the rainbow is made up of spectral analysis of sunlight, all the colors visible there are present on paper and pen. Such as here-

Image - Visible Spectrum (from Wikipedia)

Now, if you want, you can enlarge this image and share it in 101 places by drawing steep spots. And by doing this you will get two different colors on both sides of those spots. If you can name all of them one by one, then all the colors of those 101 names exist in the rainbow. For example, there are many middle colors in the middle of green and yellow.

But so many names will not be of any use to us. As much as our eyes have the ability to differentiate, only those that we have different names.

So how many colors of the rainbow are actually up to you. However, the way the number seven has been established, people may say it is crazy to make more noise about it.