Zero Shadow Day, a rare celestial phenomenon, is set to grace Bengaluru on August 18, offering a unique experience for students and astrophiles in the region. This phenomenon occurs twice a year for individuals and objects located between the Tropic of Cancer and the Tropic of Capricorn (23.5 and -23.5 degrees latitude).
On Zero Shadow Days, people erect vertical poles and various objects to witness this cosmic event, where the sun’s position leads to a momentary absence of shadows. Astrophysicist Debiprosad Duari explained that visible light typically produces shadows unless it falls exactly above the object. During these special days, the Sun’s declination is equal to the latitude of the observers, causing the sun to be directly overhead at noon. This alignment results in shadows disappearing for a brief period.
The Astronomical Society of India elaborates that individuals residing between +23.5 and -23.5 degrees latitude experience this phenomenon, as the Sun’s declination matches their latitude twice annually. This unique occurrence is due to the Earth’s axial tilt and the way sunlight interacts with objects during specific solar alignments.
Previously, Bengaluru experienced Zero Shadow Day on April 18 this year, when all vertical objects momentarily lost their shadows at 12.17 pm. Hyderabad also witnessed this phenomenon on August 3 at 12:23 pm and on May 9 this year. The phenomenon provides a captivating glimpse into the cosmic interactions that shape our daily experiences on Earth.
