Daijiworld Media Network - Bengaluru (SP)

Bengaluru, Apr 24: Tuesday April 24 happens to be 'zero shadow day'. In the afternoon today, one can personally check that for about an hour, their own shadows become non-existent in the afternoon.

In normal days, the length of one's shadow gets shorter as the day advances. However, in the afternoon, the shadows grow in length till evening. On 'zero shadow day', no shadows can be seen.

Zero shadow days happen twice in the areas falling between the tropic of cancer and tropic of Capricorn twice every year. This ophenomenon happens when the earth, when rotating around the sun passes through 23.5 degree south latitude and 23.5 degree north latitude. Astronomers say that the areas which fall beyond these two lines never experience zero shadow days.

No equipment is necessary to observe this phenomenon. Keeping a glass tumbler under the sun or planting long poles or sticks is enough to make sure that their shadows are not seen around them.

Director of Jawarharlal Planetarium, Pramod G Galagali, says that Public Outreach Committee of Astronomical Society of India has created an android application titled 'zero shadow day', which can be downloaded to get information about this feature even in Kannada.

Zero shadow happens when the sun crosses over from summer solstice to winter solstice and vice versa. When the sun is directly over our heads on April 24 (around 11.30 am and 12.30 pm), none of the things will have their shadows. The timing of this phenomenon changes from place to place by a few minutes. For example, this feature can be witnessed in Chennai before Bengaluru and in Mangaluru after Bengaluru. This phenomenon gets repeated on October 18.

In India, zero shadow day never happens in places like Chandigarh, New Delhi, Lucknow etc as they are located on the other side of the tropic of cancer.