What is the physics behind this circular rainbow in the sky?

[D3mon]

What physics phenomena is being demonstrated in this picture?

http://teachers.dadeschools.net/jkaelin/images/extra_credit2.jpg

 

[Danger]

Welcome to PF, D3mon.
The most likely one is refraction of the light, but there would also be the actions of water that caused the ice formation, freezing of the water, etc..

Or is that something other than ice?

 

[schroder]

Looks like a circular rainbow. What ever craft was used to take the picture (plane, space shuttle) had to be fairly high in the sky. All rainbows are circular when viewed from above.