Did you know, by comparing the shadow length in a distant city situated along the same longitude at the same time as Zero Shadow Day (ZSD) in our city, the circumference of the earth can be calculated?
Given that the weather holds up, the Second Zero Shadow Day phenomenon this year at the B.M. Birla Planetarium here can be observed on Thursday (August 3) at 12.23 p.m., informed director of G.P. Birla Archaeological, Astronomical and Scientific Research Institute K.G.Kumar here on Tuesday.
This phenomenon occurs twice a year when the sun is directly overhead and thus no shadow of any vertical object can be seen, and is because of the tilt of the earth’s axis and its rotation around the sun. This tilt causes the angle of the sun’s rays to change throughout the year, which in turn shows various lengths and directions of shadows, he explained.
