History of Time Zones
Before the late nineteenth century, time keeping was essentially a local phenomenon. Each town would set official time on their clocks according to the motions of the sun and the citizens would set their watches and clocks accordingly. However, because of the nature of how local time was kept, the railroad companies experienced major problems in constructing timetables for the various stops. Timetables could have only become more efficient if the towns and cities adopted some type of standard method of keeping time.
In 1878, Sir Sanford Fleming, a Canadian, suggested a system of worldwide time zones that would simplify the keeping of time across the Earth. Fleming proposed that the globe be divided into 24 time zones, each 15 degrees of longitude in width. Since the world rotates once every 24 hours on its axis and there are 360 degrees of longitude, each hour of Earth rotation represents 15 degrees of longitude.
In 1884, an International Prime Meridian Conference was held in Washington D.C. to adopt and standardize the method of time keeping and determined the location of the Prime Meridian. It was agreed that the longitude of Greenwich, England would become zero degrees longitude and the 24 time zones were established relative to the Prime Meridian. It was also proposed that the measurement of time on the Earth would be made relative to the astronomical measurements at the Royal Observatory at Greenwich. This time standard was called Greenwich Mean Time (GMT).
The Universal Time Coordinate (UTC) has replaced GMT as the standard legal reference of time all over the world in 1972. UTC is determined from six primary atomic clocks that are coordinated by the International Bureau of Weights and Measures (BIPM) located in France.
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Concepts and TerminologyConfidential, TRX Inc.7 November 2007