Zero Shadow Day

The Students of Department of Physics traced the shadow of various objects at different times on April 24, 2019 as there will be no shadow exactly at 12.07 noon when the sun will be exactly at zenith. When the sun is at the zenith (the highest point in the sky) its rays will be hitting a particular point exactly perpendicular to the surface. This will make the shadow be exactly under any object, making it look like there are no shadows. The apparent path of the Sun goes from 23.5 degrees south of our equator to 23.5 degrees north of it through the year, so every place on the Earth between the Tropics of Cancer and Tropics of Capricorn, will have two days in a year where the Sun will be directly overhead once during `Uttarayan’ (summer solstice - when sun begins its movement away from the Tropic of Capricorn, towards the Northern Hemisphere) and once during `Dakshinayan’ (winter solstice - period when Sun travels back from Cancer to Capricorn that is from North to South). These are called Zero Shadow Days or ZSDs for that location. For India these days happen during the time period from April to September.