ZERO SHADOW DAY

 A zero shadow day is a day on which the Sun does not cast a shadow of an object at noon, when the sun will be exactly at the zenith position.Zero Shadow Day is a rare celestial occurrence that happens twice a year. When the sun is at its greatest position in the sky, no shadows of any object or living being are visible.  Zero shadow day happens twice a year for locations between +23.5 and -23.5 degrees of latitude (between the tropics of Cancer and Capricorn, respectively). The dates will vary for different locations on Earth. This phenomenon occurs when the Sun's declination becomes equal to the latitude of the location. On a zero shadow day, when the sun crosses the local meridian, the sun's rays will fall exactly vertical relative to an object on the ground and one cannot observe any shadow of that object.

Kolkata to have zero shadow moment on June 5 the zero shadow moment will be around 11:34 am.This happens twice a year when the sun is exactly overhead.The city is around 2,500 km from the equator and around 93.5 km from Tropic of Cancer, the imaginary line which passes close to Krishnanagar in Nadia district.For Kolkata the first zero shadow day this year will be on June 5, 2022 and the zero shadow moment will be around 11:34 am. However in other locations the day of zero shadow will vary depending upon their position between the two Tropics, Duari said. On its return path (called Dakshinayan) the sun will again be exactly overhead in Kolkata on July 7, at around 11:41 am and the day will be the second zero shadow day of the year, he added. Every year on the zero shadow days, students and astrophiles who are located between the two Tropics erect vertical poles, different objects and sometimes even stand outside to see for themselves the cosmic event.This phenomenon lasts for a small part of a second, but the effect can be seen for a minute to a minute-and-a-half.