In October 1884, forty-one astronomers and representatives from 25 countries gathered in Washington D.C. for the International Meridian Conference to recommend a common prime meridian for geographical and nautical charts that would be acceptable to all parties concerned. It was 125 years ago this week.
By the end of the difficult summit, which dragged on until “smoke came out”, Greenwich, UK had won the prize of longitude 0º by a vote of 22 to one, with only San Domingo against and France and Brazil abstaining. One of the main reasons for British victory over key rivals Washington, Berlin and Paris, was that 72% of the world’s shipping already depended on sea charts that used Greenwich as the Prime Meridian. It was also convenient that Greenwich’s location insured that the 180º meridian, where formally the date line should be located, mostly passed over water.
The International Date Line, however, was never defined by any international treaty, conference, law or agreement. Only in the early 20th-century, the mapmakers created it based on the recommendations of the hydrographic departments of the British and the American Navies. The original international dateline was almost straight, but in 1921, when the Swedish-Canadian polar explorer Vilhjalmur Stefansson (1879-1962) tried to claim the Russian lands east of the dateline for Canada, the dateline was switched to prevent further disputes.
Choosing time zones had been a great matter of controversies since. The Communists in China reverted an earlier system of having five time zones for a single Beijing standard time, an anomaly that created three and half hour time difference across Chinese-Afghan border. Equally large India snubbed its former rulers by choosing to be +0530 GMT (“turn your watch upside down if you’re in the UK, and that’s the time in India”, the saying goes) and Nepal uniquely had +0445 GMT, a visage of an absolutist past. Until 1995, Kiribati, which straddled the International Date Line (half of its islands were a day ahead of the others), and its change in 1995 created a dent on the date line.
Ideally, there would be 24 time zones across the world, but at the last count there were 39.
There is also an informal Central Western Standard Time at +0845 GMT time zone in Australia’s largest state, Western Australia. The area maintained its fixed offset from GMT during daylight-saving. The total population of this informal time zone is estimated at just 200.
http://en.wikipedia.org/wiki/Time_in_Australia