When there is a rainbow, why is the sky inside the arc a lighter colour/brighter than the sky outside of it?

Question

When there is a rainbow, why is the sky inside the arc a lighter colour/brighter than the sky outside of it?

In: 9

Answer 1

Light is refracted when it hits the curved surfaces of water droplets in the air and different wavelengths come out at different angles. Light is refracted in the whole area of a rainbow into different wavelengths (colors). But, in most of the circle, the refracted wavelengths recombine with wavelengths from other droplets to form white light again (the bright area). The bands of color we usually think of as a rainbow are just the edge where the refracted wavelengths don’t line up with those from other angles.