A zero shadow day happens when the Sun is almost directly overhead, so its rays fall nearly perpendicular to the ground. Because of this geometry, vertical objects cast shadows that shrink to a point beneath them or nearly disappear. This effect only occurs in regions between the Tropic of Cancer and Tropic of Capricorn, where the Sun can reach the zenith. It usually happens twice a year for a given place and is a clear demonstration of Earth’s axial tilt and its orbit around the Sun. Want more interesting content like this ? Follow gravitonomy :) Via : Unknown No copyright infringement intended. Kindly DM for Credit/Removal/Collaboration :) #zeroshadowday #shadow #sun #science #naturalphenomena