Did you ever ponder how despite having different times, clocks around the world are in synch with each other? This is necessary so that everybody has similar timings in day and night, and the sun is at the top with brightest light at noon in every place. It’s an interesting phenomenon how time is managed with very high precision and accuracy around the globe, maintaining all the clocks in sync to avoid any kind of loss.
Well, the earth revolves around the sun and spins around its own axis. If we calculate, the earth spins 15 degree per hour around its own axis and completes the full circle in 24 hours. Accordingly, the earth regions are divided into 24 time zones, each time zone is 15 degree wide in the longitudinal plane. To start with, there must be a reference line. Thus, the longitudinal line which begins at Greenwich (near London, UK) has been defined as the reference line for Universal Coordinated Time (UTC) and is called as UTC= 0.00 h. The other time zones are either added to UTC=0.00 h or subtracted from it according to position. The universal coordinated time is managed and provided by the supreme metrological organisation International Bureau of Weights and Measurers (BIPM), located in France...read more on NOPR
B. Gowsika& G. Chelladurai
Dr N.K. Prasanna and Dr S.K. Varshney