What could cause these black spokes? It's an amazing phenomenon that creates these familiar shadows. These rays originate from dark spectacular west of Lake Michigan, this image was taken in July 2010 from Pentwater, Michigan, USA. These are the clouds near the horizon, tinged with red that block sunlight, resulting in prolongation of their unusual dark columns converging into the sunset. The sunlight will reflect in the air behind the cloud, which makes this air column unusually dark. These shadows of clouds are just the complement of crepuscular rays, these gaps quite common in the clouds where sunlight rushes. We see in this picture few rays crepuscular. | | The colors of the sunset when the sun is low on the horizon are due to light rays that pass through a thicker atmosphere to the horizon and vertically. Sometimes, opposite the Sun in the east, one can also observe anti crepuscular rays. This phenomenon is also called the arch anti twilight, or girdle of Venus. Image: Photograph of Lake Michigan. Credit & Copyright: Kurt Voigts
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