In the absence of a prism, what is making the photons in a rainbow congregate into bands of separate colors?

Question

And why are the colors are always in ROYGBV order?

In: 5

Answer 1

This is 16 hours old but no one really answered the last question; the colors of the rainbow go in that order because the different wavelengths of light are bent at different angles by a prism.

All waves refract when they hit a boundary between 2 different densities (like water/air and glass/air, but also different layers within a solid material or even layers of the atmosphere). I don’t know if it’s as simple as “different wavelengths always refract at different angles” but in a prism, that’s what’s happening.