Mountain Shadows

No, it's not Sauron reaching across from Mount Doom. It's just the shadow of Mount Rainier in the northwestern U.S., cast across the underside of the clouds at sunrise.

At the brief moment of sunrise and sunset, the rays of sun, peeking past the edge of the curving earth, can shine upward toward a horizontal deck of stratus or altostratus clouds, lighting them from below. If a mountain nearly bumps its head on that deck of clouds, it can cast a shadow across it. As with sunbeams and shadowbeams, the lines of the shadow converge back to the sun's position.


Seen from the top of Mount Rainier, facing away from the sun at sunset, the cast shadow looks triangular. That triangular shape is not the mountain profile you're seeing, but, again, it's the lines of perspective of the edges of the broad mass of shadowed air running back to infinity through lighter illuminated vapor.
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On Halloween, Monday, October 31, from 11-12:30, I'll be lecturing on color and light at the Canzani Center Auditorium at the Columbus College of Art and Design in Ohio. It's free and open to the public.

Links and Credits
More photos of Rainier casting shadows at Geekologie
The second photo of the mountain shadow is by Dale Ireland from Atmospheric Optics
Thanks, Chris Vosters

Previously on GurneyJourney:
Reflected Sunbeams
Shadowbeams
Sunbeams