Hyderabad, Aug. 3 -- Visitors and invited students at the BM Birla Science Centre on Tuesday witnessed the Zero Shadow day at around 12.31 pm.

Zero shadow day is observed when the Sun does not cast a shadow of an object at noon, when the sun will be exactly at the zenith position. The phenomenon is witnessed twice a year in locations between +23.5 and -23.5 degrees of latitude (between the tropics of Capricorn and Cancer).

During this, the sun's position is at its zenith (highest imaginary point directly above a location, on the imaginary celestial sphere). Since the earth is tilted at 23.5 degrees to the plane of its revolution around the sun, for people living in +23.5 and -23.5 degrees latitude, the sun's angular distance of a point ...