For background, I was on a tour coming back from Ballestas Islands just off of Peru, around 11:00 a.m., no rain (it’s a desert area), sky was partly cloudy. The phenomenon stayed a couple of minutes. As we progressed, the colours merged to a strand of amber.
Cloud iridescence! . Typical with thin high atmosphere clouds. When very small ice crystals or water droplets form the cloud they can diffract the light from the sun, causing an interference pattern to form. Not entirely dissimilar from an oil slick.
Thanks a bunch. Are they more common in hot countries? Never seen them in Canada.
Am Canadian. Have seen them. It’s more about altitude than lattitude.
Edit: Spend a little bit of every day looking at the sky. Day or night, it’s often magnificent.
I see them in the Midwest quite regularly. If you’re outside enough, you see them.
Last night’s sky was especially amazing.
Aurora?
What part of Canada? If west coast, probably the clouds are just typically too low and thick.
Northern Ontario
Super interesting that this is an entirely different mechanism from a rainbow.
The way they are describing it isn’t entirely accurate.
It’s not an interference pattern, it’s basic refraction. And since each wavelength of incoming “white” light is refracted slightly different, you get the rainbow display
You are correct! I think the use of the word “diffraction” is a bit confusing because “diffraction patterns” are an interference effect.
So is this any different than a rainbow? The path of light must be at least different since rainbows only occur in the opposite direction of the Sun.
No it’s the same effect. Suspended water particulate refracting sunlight.