system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: why does light from artificial light sources not form a rainbow when it's raining?

I know that a rainbow is formed from the separation of white light. But why does it not occur from artificial light sources? This occurred to me when it was drizzling under floodlights.
gpt
Well, first of all, you'd have to be looking away from the floodlights, just like you have to look away from the Sun to see a rainbow. The center of the circle of a rainbow is the point in the sky exactly opposite the sun, or other light source.

When you look away from a floodlight, you are looking into the ground, and there are very few raindrops there to reflect the light. You need a lot of raindrops to reflect enough light to make a rainbow, because the reflection off each individually is very dim.

So, the ingredients of a rainbow are: a bright light, capable of penetrating many miles through drizzle, and the drizzle itself, consisting of many millions of raindrops, each contributing a very small amount to the total reflected light.