“When the Sun is directly overhead, the Earth’s surface will remain devoid of any cast shadows.”
“Bengaluru to Commemorate Zero Shadow Day Again on August 18. This unique celestial phenomenon, first noted on April 25 in the city, occurs between the Tropics of Cancer and Capricorn.
What’s Behind This Phenomenon?
When the Sun is directly overhead, no shadows form on the Earth’s surface. This signifies the Sun reaching its highest point in the sky, causing shadows to shorten and vanish.
Understanding Zero Shadow Day A distinctive celestial occurrence, known as zero shadow day, happens twice yearly within +23.5 and -23.5 degrees latitude zones. During this period, the Sun reaches its zenith, resulting in no object or person casting a shadow.
According to the Astronomical Society of India (ASI), when the Sun is precisely at the zenith, objects don’t cast a shadow. ASI’s website states, ‘For those within +23.5 and -23.5 degrees latitude, the Sun’s declination matches their latitude twice a year – once during Uttarayan and once during Dakshinayan.’ This alignment leads the Sun to be directly overhead at noon on these days, erasing all shadows on Earth.
Zero Shadow Days were previously observed in cities like Hyderabad, Mumbai, and Bhubaneswar.”