Time zone is a certain area of Earth in which people are using united and standardized time. Earlier people were using local time which was known as Sun time and which was different in every place on Earth. Because of development of telecommunications and railways it become inconvenient. The problem was sold by time zones. Each time zone includes certain regions which are using united Sun time. Time zones are generally based on meridians which form one hour difference between collateral time zones. However, this division is not so simple and universal as it may sound, because usually borders of time zones are drawn along borders of countries, states and other administrative units. Today there are 24 times zones, but the total number of time-shifting is 51. Nowadays only 42 of them are used, but other 9 are not used any more.
In the year of 1878 sir Sandford Fleming developed the system of time zones for whole world which is still used. Sir Sandford Fleming was a Canadian engineer and inventor who not only proposed worldwide standard time zones, but also designed Canada’s first postage stamp. He left huge influence on surveying and map making, as well as on engineering of the Intercolonial Railway and the Canadian Pacific Railway. It should be mentioned, that he was a founder of the Royal Canadian Institute, which is a science organization in Toronto, and a founding member of the Royal Society of Canada. Railway companies of United States of America started to use Fleming’s system of time zone only on November 18, 1883.
When sir Sandford Fleming missed his train in the year of 1876, when he was in Ireland, because he had a schedule, which was listed p.m. not a.m., he offered to the world a single 24-hour clock, which was located at the centre of the Earth, not linked to any meridian. Later he linked it to the so called anti-meridian of Greenwich, which is 180 degrees now. He suggested that standard time zones can be used locally, but they have to be subordinated to his single world time or, as he called, to Cosmic time. He was promoting his system at major international conferences and experienced different reactions. However, by the year of 1929 all major countries in the world had accepted his system of time zones.
Greenwich meridian or, in other words, prime meridian, which is based at the Royal Observatory in Greenwich, was established by sir George Airy in the year of 1851. The International Meridian Conference in selected the meridian which was passing through Greenwich as the official prime meridian. France abstained from voting and continued to use the name of Paris meridian for several decades. The prime meridian is passing through the Airy transit circle of the Greenwich Observatory and is marked by a powerful green laser shining across the London night sky. The Greenwich Observatory, which is known as the Royal Observatory, is an observatory which is situated on a hill in Greenwich Park and which played a major role in the history of astronomy and navigation.