Before Newton did his prism thang, I’m guessing people had noticed that you could produce pwetty colors by passing light through various lenses and prisms. But they must have been awed to see this huge, multi-colored thing in the sky when it was sunny + raining. So, before Newton’s explanations, what was the common thinking on what rainbows were? Did people have an inkling that white light was composed of all colors?
The work on refraction, interference, and diffraction pretty much established the wave theory and buried Newton’s ideas about the corpuscular nature of light. Then along came Max Planck, et al.
If you’re interested, you can scroll down and have a look at what it says on “Rainbows in religion and mythology,” but I don’t know whether such things were believed literally or whether they were taken as poetic or whimsical. Also, some of these things, such as the Bible passage Alessan quoted, give different kinds of answers to the “What is a rainbow?” question from the answer Newton gave. (Kind of like the question “What is a traffic light?” could be answered either “It’s a device made of light bulbs and switches” or “It’s a signal to tell cars when to stop and go.”)
I remember reading in a Scientific American article many years ago that even in the late 1800s most Americans still believed rainbows were divine phenomena.
What lay people think and what Scientists think are usually quite different in all ages.
Does anyone have any idea about the *non *Judeo-Christian world? Wonder what they thought. China was pretty advanced, think they had any idea? What about Persia?
