BENGALURU: The city will witness an astronomical phenomenon known as the Zero Shadow Day on Friday (August 18) wherein no shadow of any person or object will be seen. This will be the second time this year that the city will be witnessing the phenomenon and will last about two minutes from 12.24 pm.
Zero Shadow Day is when the Sun is directly overhead and no shadows are formed. The Sun reaches its highest point in the sky which results in the reduction of the length of the shadow to the extent that it is no longer visible. The phenomenon occurs in places that lie between the Tropic of Cancer and the Tropic of Capricorn twice in a year.
“The phenomenon is observed on the day of the equinox when the length of the day and night is equal. On those days, the Sun rises exactly in the East and sets exactly in the West. At noon, the Sun is directly above the head along the Equator on March 21 and September 20”, astrophysicist Dr Anand explained.
Further, he said, “As we think, the Sun dies not rise directly in the East and set in the West every day — it could be slightly towards the North or the South and hence, it is not directly above the head on all days. In places not along the Equator, but between Tropic of Cancer and the Tropic of Capricorn, the phenomenon occurs on different days. In Bengaluru, it occurs on April 24 or 25 and again on August 18”.
Any object standing straight will create no shadow at noon on these days. Hence, these two days are called as Zero Shadow Day. This phenomenon does not occur in places above the Tropic of Cancer or below the Tropic of Capricorn, Dr Anand explained.