When watching the sun above cold water, you sometimes can observe an unusual phenomenon. The sun does not set as a “ball”, but seems to diverge at the horizon. Sometimes it even appears as a bright horizontal line which adapts a shape reminding of Bayly´s Beads during a total solar eclipse. The last bright beads sometimes disappear only at a few minutes after sunset. This phenomenon was first documented by the British amateur astronomer John Franklin-Adams. He observed the phenomenon several times from board of a ship and attributed it to the swell near the horizon.
Even if it may sound absurd, the conditions above a sea of clouds are similar to those above the ocean. The suface of the moving clouds is undulated, and also the surface of the clouds is cold, just like that of the sea. So the light gets reflected and the light-emitting object (in this case the sun) gets lifted optically. The bright beads then shine throug the gaps of the waves, no matter if they are made of water or of clouds (photo spread).
Author: Claudia Hinz