Ujjain (Madhya Pradesh): Ujjain, a holy Indian city in state of Madhya Pradesh through which passes the Tropic of Cancer, witnessed a 'Zero Shadow Day' on Saturday (June 21).
The rare celestial event occurs every year in Ujjain when vertically standing objects (like poles or people) do not cast any shadow at noon. This is because of the Sun's perpendicular position to the Tropic of Cancer in the northern hemisphere.
Another interesting fact is Ujjain has historical importance in Indian astronomy and it was considered the 'Greenwich of India' in ancient times.
CM Mohan Yadav too witnessed the Zero Shadow Day in Ujjain's Mahidpur tehsil.
Scientific explanation of phenomenon
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According to Government Jiwaji Observatory superintendent Dr RP Gupt, the event is caused by the Earth's revolution around the Sun and its 23.5° tilt.
This year, the Sun reached its northernmost position on June 21, which is directly above the Tropic of Cancer - the latitude crossing through Ujjain.
Due to this, the sunlight fell vertically on the city of Ujjain at 12 in the noon (as per local time). With this, all the upright objects did not cast any visible shadow for a few minutes.
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Also the longest day of 2025
Dr Gupt explained that on June 21, the Sun’s position was 23 degrees, 26 minutes, and 17.86 seconds North, aligning perfectly with the Tropic of Cancer. Using a special cone-shaped instrument, visitors at the Jiwaji Observatory were able to witness this unique event in real-time.
According to the Sayan system of calculation, on June 21 the Sun was supposed to be positioned at 0 degrees, 09 minutes, and 02 seconds in the zodiac sign of Cancer.
Longest day of 2025
Not just a day of disappearing shadows, June 21 also marks the longest day of the year in the northern hemisphere, known as the 'summer solstice.'
On Saturday, sunrise occurred at 5:42 am in Ujjain and the sun will set at 7:16 pm, making the day 13 hours and 34 minutes long, while the night will be only 10 hours and 26 minutes.
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Now, nights to get longer
After this date, the Sun will begin its southward journey, a phase called Dakshinayan, during which the days will gradually start getting shorter.
This continues until September 23, when day and night will be equal in length - an event known as the autumn equinox.
The Jiwaji Observatory has invited science enthusiasts, students, and the public to witness this rare astronomical event and learn more about the Earth’s motion and solar geometry.
