The city will have its zero shade moment on June 5 when there is no shade from the sun at a particular time of day.
It happens twice a year when the sun is directly overhead, astrophysicist Debiprosad Duari said on Wednesday.
“Any form of visible light falling on an object generally casts a shadow, unless it is directly above the object. People and any object, anywhere in the world, living between the Tropic of Cancer and the Tropic of Capricorn (+23.5 and -23.5 degrees latitude) lose their shadow, albeit momentarily, twice a year. These two days are called shadowless days,” he said.
The city is about 2,500 km from the equator and about 93.5 km from the Tropic of Cancer, the imaginary line that passes near Krishnanagar in Nadia district.
For Kolkata, the first zero shadow day this year will be June 5, 2022 and the zero shadow time will be around 11:34 a.m. However, in other places, the zero shadow day will vary depending on their position between the two tropics, Duari said.
On its way back (called Dakshinayan), the sun will once again be exactly over Kolkata on July 7, around 11:41 a.m. and the day will be the second zero shadow day of the year, he added.
Every year on zero shadow days, students and astrophiles who find themselves between the two tropics erect vertical poles, different objects, and sometimes even stand outside to see the cosmic event for themselves. In different cities where the day of zero shadow has already happened this year, experienced the moment of zero shadow when every object under the sun lost its shadow for a few moments. Duari said that this event also reminds people of the movements and position of celestial bodies relative to Earth which have direct links to events on the planet like changing seasons, tides and eclipses in addition to times of d shadow zero.
The sun is almost never exactly overhead at noon, but usually passes a little lower in altitude, a little north or a little south, he added.
(This story has not been edited by the Devdiscourse team and is auto-generated from a syndicated feed.)