The students and visitors at Birla Science Centre had a fascinating Tuesday as they witnessed a rare phenomenon named the Zero Shadow Day at 12:31 pm. The phenomenon of Zero Shadow is when the sun does not cast a shadow of an object at noon. This implies that the sun will be exactly at zenith position (exactly above an object)
This is a rare occurrence that happens twice a year, only at locations between +23.5 and -23.5 degrees of latitude (between the Tropics of Capricorn and Cancer). The earth is titled at 23.5 degrees to the plane of its revolution around the sun, and the people living +23.5 and -23.5 degree latitude will find that the sun's angular distance from a point north or south of the equator is equal to their latitudes.
Since this happens twice a year once, it will happen when it moves north of the equator and another day when it moves south of the equator. The earlier version of the zero shadow day occurred on May 9. The dates of the Zero Shadow Day vary for different locations on the earth as it depends on the angle of the earth's inclination and the latitude of the region to be equal.