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SUNBEAMS UNDER THE ICE

Sunbeams are seen by the diver under sea ice cracks on a sunny day. The word "sunbeam" is commonly used for rays of light formed by the shadows of scattered clouds in the atmosphere. When sunbeams form from the sun shining through a gap in the clouds, they are bright; bright sunlight streaming through sea ice cracks is analogous. Other names for sunbeams are "crepuscular rays", "Buddha's fingers", "ropes of Maui", "sun drawing water", and "backstays of the Sun." The contrasting light scattering by seawater inside and outside the sunbeam makes the sunbeam visible to the diver. Depending on the sea ice crack, the sunbeam may strikingly illuminate the seafloor with a spot beam, a long band of light, or both in combination.



Sunbeams are usually one or more shafts of light appearing to diverge from the sun. Sunbeams are parallel and the viewer's perspective makes them appear to diverge due to the small distance of the viewer to the sunbeams compared with his distance from the sun.

Sunbeams have been depicted in Western art since medieval times where they were sometimes shown emerging from a gap in the clouds created by the hand of God. When Western painting increasingly depicted cloud cover after 1500, sunbeams have been painted realistically and were no longer shown simply as thin lines.

1: Journal of the Optical Society of America A, Optics and Image Science 4(3):609-611, 1987; 2: Applied Optics 30(24):3514-3522, 1991

Text ©Peter Brueggeman. Photographs ©Norbert Wu. Photographs may not be used in any form without the express written permission of Norbert Wu. Norbert Wu no longer grants permission for uncompensated use of his photos under any circumstances whatsoever; want more info?