Time Zones: A Brief History 

From days of old, there has been a consciousness of time and time schedules. Be it just sunrise, noon and sunset as the outlining time features of the day, man has always followed a repetitive pattern of life based on this. His entire metabolic functioning too was in sync with every part of the day apart from his patterns of sleep, feeding and work. 

Shadows &Sundials:

The earliest records of calculating time have been by studying the location of the sun in the sky and its relation to shadows. The Egyptians were innovative in inventing the sundials and water / sand clocks. The sundial was initially a pole or a tree that used to be in the centre of the village or palatial courtyard, and the time of day would be determined by the shadow of the object in perspective. The day was divided into twelve hours of light and likewise twelve hours of night, totaling in twenty four hours a day. However, its main disadvantage was that it could not be followed during the night. 

Water & Sand Hourglasses:

The sand or water clocks, which gave rise to the hour glass, were two conical jars that had an opening at the junction of the pointed ends, when joined one over the other. Water or sand was placed in the upper container and was allowed to fall through into the lower container. Gradations on the container indicated which time of day it was. However this system too had its drawback; water or sand had to be regularly refilled. 

Coordinated Universal Time

Travelers out at sea could not follow these forms of calculating time and dates, and with the onset of the Railways, a new dilemma appeared. People could not conduct businesses without referring to the need for standardized time. Besides, with travel made quicker, and the need for a Train Time Table required for the Transportation Department, a solution had to be found. This was the main inspiration behind the Canadian rail engineer, Sir Stanford Fleming 's (1827 - 1915) idea of time zones. He proposed his innovative thought in 1878 which came to be popular as the Coordinated Universal Time (UTC).

Greenwich Mean Time

Since the earth is round and rotates on its axis around the sun, Fleming introduced the concept of longitudes. Longitudes are imaginary lines, drawn across the earth from north to south. Each longitude was spaced 15 degrees apart, covering twenty four zones and encircling 360 degrees accurately. Every partition was a specified time zone with a one hour difference. The Royal Observatory at Greenwich, London, which played a major role in the navigation of sea borne vessels, was to be the starting point. Therefore, the longitude passing through the Greenwich zone was marked as the Prime Meridian ( 0 degree longitude), the Greenwich Mean Time, and the line passing through the Pacific Ocean on the opposite side of the earth was marked as the International Date Line. The time at the Prime Meridian is denoted as GMT, and those to the east of it have a time notation of GMT (+ n ) indicating they were ahead of the Prime Meridian , while on the other hand, places to the left , are noted as GMT (- n ) ; n' being the number of hours.

This idea picked up pace and popularity with almost every nation over time, and the UTC is followed universally. I would now be able to calculate the time in any part of the world based on the longitudinal location of that place. Countries that stretch across multiple time zones have notable time differences likewise. For example, Kiribati has three time zones. On the other hand China follows only a single standard time across the entire country, although it spans across three time zones. The introduction of time zones has made documentation of time easier, uniform and precise. Without it, we would be living in a chaotic world.

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