Lucknow University astrophysicist Alka Mishra demonstrated Zero Shadow Day to the university students on Tuesday.
On Zero Shadow Day, when the Sun crosses the local meridian, its rays fall vertically relative to an object on the ground. At that time, our shadow becomes either ‘zero’ or smallest. Contrary to popular belief, the sun is never right above us even at noon, except on Zero Shadow Day. It is usually a little north or a little south at low altitudes, they said.
Mishra told the students that there is only one day in a year when the noon Sun shines right above our heads at places falling between 23.5°N and 23.5°S degree latitude. “This is the reason why even our shadow leaves us at that time. Astronomers call this phenomenon of no shadow formation Zero Shadow Day,” she explained.
For a very short time on June 21 (Summer Solstice) our shadow either completely disappears or becomes too small. Since Lucknow is located at 26.85°N latitude, absolute ‘zero shadow’ does not exist but the smallest shadow can be seen on June 21 at midday, Mishra said.
She made the students stand in a circle and demonstrated this phenomenon at 12.06 pm and explained to students Zero Shadow Day.
Professor Poonam Sharma and Prof. Amritanshu Shukla were also present and they too shared information about the sequence of events involving the Sun and the Earth with the students. They explained how these dates are also different for different places on Earth and this phenomenon occurs when the inclination of the Sun becomes equal to the latitude of the particular place.
{{/usCountry}}Professor Poonam Sharma and Prof. Amritanshu Shukla were also present and they too shared information about the sequence of events involving the Sun and the Earth with the students. They explained how these dates are also different for different places on Earth and this phenomenon occurs when the inclination of the Sun becomes equal to the latitude of the particular place.
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