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For the second time in 2023, on August 18, Bengaluru is getting ready to observe the glorious astronomical phenomena known as Zero Shadow Day. The city will experience a brief celestial event at 12:24 pm when the Sun will be directly overhead. 

This timing was determined by astronomer Alok Mandavgane. Vertical things like poles, sticks, and even humans are unlikely to cast any shadows on the ground during this period. You won’t be able to see your shadow until the sun reaches its zenith unless you jump.

What Is Zero Shadow Day?

Zero Shadow Day is a rare celestial event that astrophiles find remarkable when there are no shadows because of the tilt of the Earth and its orbit around the Sun. During this time, shadows would either cast vertical shadows or practically disappear.

As per the Astronomical Society of India (ASI), the Sun will not cast a shadow on an object – when it is exactly at the zenith position. In its website, the ASI wrote, “For people living between +23.5 and -23.5 degrees latitude, the Sun’s declination will be equal to their latitude twice – once during Uttarayan and once during Dakshinayan. On these two days, the Sun will be exactly overhead at noon and will not cast a shadow of an object on the ground.”

Zero Shadow Day: What time will the astronomical event take place?

According to scientific theory, regions between the Tropics of Cancer and Capricorn, or latitudes between 23.5 and -23.5 degrees, witness Zero Shadow Day twice a year.

On April 18 of this year, Bengaluru had Zero Shadow Day; notably, around 12.17 pm, vertical objects lost their shadows for a brief period. The same phenomena was seen in Hyderabad on May 9 and again on August 3 at 12:23 p.m.

To experience this astronomical event on August 18, be outside in the Sun in the late afternoon as the event is stated to begin at 12.17 pm is the precise moment to view and capture it.

Sceintific Theory Behind Zero Shadow Day

Over the course of a year, the sun’s route across the sky varies. Imagine a huge dome-shaped building in the sky. This celestial dome’s apex is where the zenith is situated. When the sun reaches this point, your shadow precisely aligns with the ground underneath you. This occurs only twice a year, and both occasions it only takes place on Zero Shadow Days.

How to witness Zero Shadow Day?

As the expected moment of solar noon approaches, you’ll see the progressive elimination of your shadow. Nearby objects, such poles, won’t have any shadows and appear to be hovering in midair. On your rooftop or the ground, you may place things such as water bottles, torches, bottles, rods, pipes, and more in the sunshine and see how their shadow lengths change as the day goes on. Eventually, the shadow will entirely disappear for a brief period of time about 12:24 pm. The Zero Shadow time begins now.