Rainbow question

[Pantechnicon]

If you see a rainbow why is the sky under the rainbow lighter than the sky above the rainbow ?

[Evoluzione]

Because you're looking through less cloud.

[thebraketester]

Also, the area of sky between a double rainbow is darker than the rest.

[Pantechnicon]

Evoluzione said:

Because you're looking through less cloud.

Ok why am i

[Eric Mc]

It might be to do with the fact that the raindrops (which are causing the rainbow in the first place) are denser higher up (closer to their source cloud) than they are closer to the ground. If you look at rain falling from a cloud from a distance WITHOUT a rainbow in the way, you will see this -

[Bill]

Surely it's just that the bit above the rainbow will be in the shadow of the rain cloud.

[Eric Mc]

It's probably a combination of visual effects. With the rainbow in place, it might seem that the rainbow is the divider between the light and dark zones. In reality, those zones are there anyway with or without a rainbow.

[Pantechnicon]

Thanks all
I’ve just found this on Wikipedia .
The sky inside a primary rainbow is brighter than the sky outside of the bow. This is because each raindrop is a sphere and it scatters light over an entire circular disc in the sky. The radius of the disc depends on the wavelength of light, with red light being scattered over a larger angle than blue light. Over most of the disc, scattered light at all wavelengths overlaps, resulting in white light which brightens the sky. At the edge, the wavelength dependence of the scattering gives rise to the rainbow.[5]

[thebraketester]

Walter Lewin. Does a great lecture on this on YouTube.... just watched it and it’s fascinating.....