Bengaluru is set to experience a rare celestial event known as “Zero Shadow Day” on August 18. This phenomenon occurs twice a year when people within the Tropics of Cancer and Capricorn, situated between +23.5 and -23.5 degrees latitude, witness the sun directly overhead, causing objects to cast no shadows. Astrophiles and students often observe this event by erecting vertical poles and objects, marking a cosmic occurrence. Bengaluru previously experienced Zero Shadow Day in April this year, where vertical objects momentarily lost their shadows due to the sun’s positioning.
Prelims pointer
- Tropics of Cancer and Capricorn: These are the circles of latitude located at 23.5 degrees north and south of the equator, respectively. They mark the northernmost and southernmost points where the sun can be directly overhead, resulting in the occurrence of Zero Shadow Days.
- Declination: Declination is the angular measurement of a celestial body’s position north or south of the celestial equator. It helps determine the vertical position of the sun and other celestial objects in relation to Earth.
- Latitude: Latitude is the measurement of how far north or south a point on Earth is from the equator. It’s expressed in degrees and represents a location’s distance from the equator, influencing climate and daylight patterns.
- Astronomical Society of India (ASI): The ASI is an organization dedicated to promoting and advancing astronomy and astrophysics in India. It provides a platform for researchers, educators, and enthusiasts to collaborate and share their knowledge.
- Sun’s Declination and Latitude Equality: Twice a year, for regions between +23.5 and -23.5 degrees latitude, the sun’s declination is equal to the latitude, resulting in the sun being directly overhead. This alignment leads to Zero Shadow Days, when objects briefly cast no shadows.
