Hyderabad Witnesses 'Zero Shadow Day': Here's What It Means

Hyderabad witnessed a rare celestial phenomenon known as Zero Shadow Day on Monday, where for a brief period of time around 12 PM, no shadow was visible.

The Birla Planetarium organised an event to demonstrate this phenomenon, where they placed a plate with alphabets on it, and as the Sun moved away from its zenith, the alphabets began to fade away. This phenomenon occurs due to the fact that the shadow of any vertical body is present below it and not visible on a Zero Shadow day.

K G Kumar, the Director of Birla Planetarium, explained that this phenomenon occurs due to the tilt of Earth's rotational axis, which causes the Sun's movement to appear as if it is moving from South to North and North to South.

He said that this is a celestial phenomenon which happens because of the tilt of the Earth's rotational axis. The Earth goes around the sun and it also rotates on its own axis. The axis of spin is not straight. It is tilted by 23.5 degrees. The 23.5 degrees makes the sun moment also apparently to move from South to North and North to South.

He further said, "When the Sun moves from South to North we call it Uttarayana, as on today we are moving into Uttarayana. When it comes back to the winter solstice, it is known as Dakshinayana when the Sun moves from North to South."

He said that as the Sun moves from South to North, every day it does not rise exactly from the East. It will rise a little towards the eastern side or the northern side or the southern side. Only on one particular day, that is today it exactly rises from the East and that is why at approximately 12 PM, the sun is right on the top of our head.

"The sun is at the zenith and when it happens, any vertical body which is under the sun it's shadow disappears. But the shadow has not exactly disappeared, it is below us. So if you are standing on a transparent glass floor with the sun on your top, you will still find your shadow down. For that purpose, we have a zero shadow day experiment where you see that when the moment the sun comes on the top of the plate, the complete alphabets are visible and then as the sun moves the alphabet slowly fades away," he added.

It is only visible on 2 days in a year. In the case of Hyderabad, we have got 2 events. One has happened today and the next one will happen on August 3. The time on August 3 will be 12:23.

He said that this phenomenon can be observed on only two days in a year, and Hyderabad experienced one of them on May 9, while the next one will be on August 3. This is observed when the Sun is going from South to North and other when the Sun comes back from North to South.