Bengaluru to observe ‘Zero Shadow Day’ today. Here’s all you need to know

Zero Shadow Day: Vertical objects in Bengaluru will not cast a shadow on April 25 at 12.17 pm (Representational image)

Bengaluru will observe a unique celestial event today called ‘Zero Shadow Day’. For a brief period of time on April 25, vertical objects in the city will not cast a shadow as the Sun will be directly overhead. At 12.17 pm today, the Sun will be directly overhead the city and vertical objects will not cast a shadow. This day will therefore be observed as Zero Shadow Day. Here’s all you need to know about it.

The Sun is almost never exactly overhead at noon but usually transits a bit lower in altitude, a bit to the north or a bit to the south.

However, “for people living between +23.5 and -23.5 degrees latitude, the Sun's declination will be equal to their latitude twice - once during Uttarayan and once during Dakshinayan,” according to the Astronomical Society of India (ASI). “On these two days, the Sun will be exactly overhead at noon and will not cast a shadow of an object on the ground.”

This day is therefore called Zero Shadow Day and in Bengaluru, it is observed on April 25 and August 18.

People living in Bengaluru will observe Zero Shadow Day starting at 12.17 pm in the afternoon. This is the moment when the Sun will reach its zenith and be directly overhead in Bengaluru.

Zero Shadow Day occurs twice a year for people living between the Tropic of Cancer and the Tropic of Capricorn. It occurs at different times for different places on Earth.

“This happens for places between the Tropic of Cancer and Tropic of Capricorn and is on April 25 and 18 August for Bengaluru,” said the Indian Institute of Astrophysics.