Have you ever wondered what it feels like to stand directly beneath the sun’s gaze, with no pesky shadow clinging to your heels?
Well, on May 1, 2024, the curious folk who turned up at the Association of Friends of Astronomy (AFA), Margao Centre, got a taste of this phenomenon at the stroke of noon, during their fascinating session on Zero Shadow Day, at Ravindra Bhavan in Margao.
Among others, this spectacle was experienced by 15-year-old, Sumit Mandrekar, a student of Bhatikar Model High School, Margao.
“I was amazed by what I witnessed at the astronomical observatory at Ravindra Bhavan. Using a lot of experiments, the team explained to us how the sun works. I was fascinated by this concept, so before I came here, I did a bit of research online,” says Sumit.
On May 1, at noon, Ravindra Bhavan in Margao witnessed this shadow-less spectacle.
On May 1, at noon, Ravindra Bhavan in Margao witnessed this shadow-less spectacle. So, what is a Zero Shadow Day?
Gaurav Dhumatker, of AFA, explains, “A Zero Shadow Day is a day on which the sun is exactly over your head, and does not cast a shadow of any vertically standing object at the solar noon. Or, in other words, the shadow cast will be exactly below the object. This happens when the sun is at its zenith position – for Margao, it happens at 12.30 pm IST.”
But, how did they achieve this shadow-less spectacle? Like brilliant scientific storytellers, the Goa team used a simple, yet effective, setup.
“The demonstration was done by using a vertically-standing pipe on a glass. Before the clock struck 12.30 pm, the pipe cast a shadow as an ellipse. And, as the sun came directly overhead at 12.30 pm, the pipe cast a circular shadow exactly underneath," Gaurav explained.
"If the same experiment was done on a day other than Zero Shadow Day, the pipe would not have cast a circular shadow. The shadow would be towards the northern or southern side depending on the position of the sun,” Gaurav added.
This mesmerising transformation marked the moment the sun reached its zenith, casting no shadows in its path.
For the curious onlookers, this wasn’t just a cool party trick. The session delved into the science behind this phenomenon.
They learned that Zero Shadow Day is a special day as it happens on different days for different latitudes, and can be experienced only between latitudes of +23.5 degrees to -23.5 degrees. This is because the earth axis is tilted by 23.5 degrees.
The afternoon didn’t end there. The AFA team took the audience on a solar safari. With astronomic equipment, they offered a glimpse of the sun’s surface – dotted with dark sunspots.
It was a chance to witness the raw power and beauty of our closest star.
The Zero Shadow Day session in Margao wasn’t just about the absence of shadows; it was about igniting a spark of curiosity among the people who witnessed the amazing phenomenon of the sun.
