Last week, Andreas Kohlmann of Samnaun, Switzerland, looked up and saw a 22° sun halo caused by ice crystals floating over the snowy landscape. His iPhone11 photo of the phenomenon captured something sky watchers often overlook--the 'hole in the sky' effect:
The sky inside the halo is darker than the sky outside, creating a large but subtle disk of partial darkness around the sun. It exists because the ice crystals scatter light at least 22° away from the sun. "No light is refracted through smaller angles, so the area inside the halo is dark," explains retired atmospheric optics expert Les Cowley.
"Most rays are deflected through angles near to 22° to form the bright inner edge of the halo," he continues. "Red light is refracted less strongly than other colors, so the halo's inner edge is red hued."
The 22° sun halo is the most common of all sun halos. The next time you see one, put on sunglasses to reduce the glare. You may see your own 'hole in the sky.'
https://spaceweather.com/
"Most rays are deflected through angles near to 22° to form the bright inner edge of the halo," he continues. "Red light is refracted less strongly than other colors, so the halo's inner edge is red hued."
The 22° sun halo is the most common of all sun halos. The next time you see one, put on sunglasses to reduce the glare. You may see your own 'hole in the sky.'
https://spaceweather.com/
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