Hyderabad: When the clock struck 12.12 pm on Tuesday, Hyderabad witnessed a remarkable celestial event where vertical objects appear to cast no shadow for a brief period of time. Called ‘Zero Shadow Day’, the phenomenon occurs with the Sun being at its zenith, and so the shadow was directly under the object.
Marking the occasion, Spaceadhyaan, a Hyderabad-based astronomy and space education organisation, conducted a public talk and hands-on activities at My Home Bhooja premises, to demonstrate the unusual astronomical phenomenon. About 150 enthusiastic students from LKG to tenth grade participated in the celebration.
Padmasri Naidu, the founder and CEO, Spaceadhyaan, said students from various city schools participated in the event. “We explained to them about the phenomenon and then they practically experienced it for themselves. Later, we educated them about other celestial events and the ways to watch them,” she said.
Spaceadhyaan in a press release said the phenomenon of zero shadow was caused by the tilt of the earth’s axis. The Earth revolves around the Sun once in 365 days. Due to the 23.4-degree tilt of the Earth’s rotation axis, the Sun seems to be moving from North to South and then back north, every year.
“Due to this apparent motion of the Sun, the places between the Tropics of Cancer and Capricorn witness the Sun directly overhead twice in a year— once while it apparently moves South, and next while it moves North,” the release said.
“At noon on any day when the Sun is not directly overhead, our shadow falls either towards the South or towards the North. But, on the day when the sun is directly overhead, at noon the shadow is exactly below you. This phenomenon is known as the Zero Shadow Day,” it further added.
For every point on Earth between the Tropic of Cancer and the Tropic of Capricorn, this annual celestial phenomenon occurs twice a year for places between 23.5 and -23.5 degrees latitude. For Hyderabad, the next Zero Shadow day is on August 3.