The celestial event of Zero Shadow Day graced the city on Wednesday (April 24) afternoon. Shadows evanesced from 12.17 p.m. to 12.23 p.m. as the Sun aligned precisely overhead. At the Indian Institute of Astrophysics (IIA) in Koramangala, more than 60 individuals congregated to engage in hands-on experiments and attend an informative talk on the subject.
According to the IIA, the Sun’s trajectory doesn’t follow a consistent pattern of rising exactly in the east or setting exactly in the west each day, nor does it pass directly overhead every day. This phenomenon can be attributed to the Earth’s axial tilt of 23.5 degrees, which also accounts for the occurrence of seasons.
The Sun positions itself directly over the Tropic of Cancer on June 21 (marking the summer solstice in the northern hemisphere) and subsequently embarks on a southward journey as observed from Earth, a phenomenon referred to as Dakshinayana. On September 23, the Sun aligns directly over the Equator (signifying the autumnal equinox for the northern hemisphere), before reaching the Tropic of Capricorn on December 22. Following this, it appears to travel northward, a period known as Uttarayana, and once again positions itself overhead the Equator on March 21, and so on.
Consequently, the Sun is situated directly over locations between the two tropics twice annually, with the specific day varying depending on the latitude. When the Sun assumes a position directly overhead, the shadow of a vertical object falls beneath it, resulting in the absence of visible shadows. This phenomenon is aptly named Zero Shadow Day.
In the city of Bengaluru and other locations sharing the same latitude, such as Mangaluru and Chennai, this celestial event occurs on April 24 and August 18.
