Crepuscular rays, sometimes colloquially referred to asgod rays, aresunbeams that originate when theSun appears to be just above or below a layer of clouds, during thetwilight period.[1]Crepuscular rays are noticeable when thecontrast between light and dark is most obvious. Crepuscular comes from the Latin wordcrepusculum, meaning "twilight".[2] Crepuscular rays usually appear orange becausethe path through the atmosphere atdawn anddusk passes through up to 40 times as much air as rays from a high Sun atnoon.Particles in the airscatter short-wavelength light (blue and green) throughRayleigh scattering much more strongly than longer-wavelength yellow and red light.
Crepuscular rays appear as divergent beams emanating from a distant source, in spite of the rays from the Sun being parallel when they arrive, because ofperspective. The point from which the divergent rays appear to emerge from is really avanishing point for parallel rays of sunlight.[3]
Loosely, the termcrepuscular rays is sometimes extended to the general phenomenon of rays ofsunlight that appear to converge at a point in the sky, irrespective of time of day.[4][5]
A rare related phenomenon areanticrepuscular rays which can appear at the same time (and coloration) as crepuscular rays but in the opposite direction of the setting sun (east rather than west).
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Definitions from Wiktionary
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