I don't believe it either. I agree with the condensation idea, not with ice crystals. You can see such rainbows near the Sun when it's right at the edge of a cl

I don't believe it either. I agree with the condensation idea, not with ice crystals. You can see such rainbows near the Sun when it's right at the edge of a cloud, too. (A normal cumulus cloud, not some high altitude cirrus.) And it's not the P-G singularity either. That's the bow shock condensation when you go supersonic. This is just a variant of the condensation streak you often see of the wings of a commercial airliner when they go full flaps before landing.