Today on April 24, 2025, at exactly 12:17 PM, Bengaluru will experience something truly extraordinary — a Zero Shadow Day. For a brief moment, people and objects standing upright won’t cast any shadows. Sounds like a sci-fi scene? It’s actually a fascinating natural event caused by the position of the sun. What is Zero Shadow Day Zero Shadow Day occurs when the sun is directly overhead at noon. At this precise moment, vertical objects cast no shadows because the sunlight hits them straight from above. It’s like nature’s way of playing hide-and-seek with shadows. Why does it happen The Earth’s axis is tilted at an angle of 23.5 degrees, and as it orbits the sun, the sun appears to shift north and south in the sky. For cities between the Equator and the Tropic of Cancer, like Bengaluru, the sun passes directly overhead twice a year — once while moving northward and once when heading south. That’s why Bengaluru celebrates Zero Shadow Days twice a year — usually around April 24/25 and August 18. The exact date can shift slightly due to Earth’s orbit. The science behind it According to Dr. Niruj Mohan Ramanujam from the Indian Institute of Astrophysics (IIA), Zero Shadow Day occurs only in locations between the Equator and the Tropic of Cancer. During local noon, the sun reaches its zenith (highest point in the sky), and its rays fall vertically on the ground. Outside of these latitudes — in cities farther north or south — the sun is never directly overhead, so they don’t get this phenomenon. Which cities experience it This isn’t unique to Bengaluru. Many Indian cities between the Equator and Tropic of Cancer experience it: Why it matters Zero Shadow Day isn’t just visually impressive — it’s also a fantastic educational moment. It helps students and curious minds understand concepts like Earth’s rotation, axial tilt, solar angles, and seasonal changes. It’s nature’s way of teaching astronomy in the real world. So, step outside at 12:17 PM, look down and be amazed when your shadow disappears.
