Delhi students measure earth's circumference on solstice

City students today celebrated the summer solstice this year by replicating an experiment conducted thousands of years ago by Greek mathematician-cum -astronomer to measure the earth's circumference.
In 240 BC, Eratosthenes, had made the calculation using knowledge of angle of elevation of the sun at noon.
"Using simple backyard tools like an upright stick, while being present at any given location and then using concepts of geometry and trigonometry, it is possible to calculate the circumference of the earth with fairly accurate results," Rishabh Jain of the city based organisation SPACE said.
The organisation has been working towards popularisation of astronomy in the country and has been carrying out this activity among students for the last four years.

"While, this measurement can be done on any day of year, on days of Equinox and Solstices the sun is directly overhead on the equator or Tropics of Cancer or Capricorn which makes calculation easier," Jain said.
Shreya Agarwal, one of the students taking part in the project at the India Gate said," It was a lot of fun doing this. I think it is something which everyone must try at least once in their lives."

When asked about the objective of this experiment, Jain said "The motive is to show people that knowledge of science can also be gained through simple everyday objects and it doesn't always require complicated equipment."

Solstice is derived from the Latin words sol (the sun) and sistere (to stand still). The summer solstice occurs when the tilt of a planet's semi-axis, in the northern hemisphere, is most inclined toward the sun, and unofficially signals the start of summer in the Northern hemisphere.
All around the world, various cultures and countries celebrate the day in the form of various festivals, such as Midsummer or St John's Day in Christianity and Saint Jonas' Festival in Lithuania.