Greenwich Mean Time: What Is It and Why It Matters

   For some people, time is simply the standard by which we hope to get to where we are supposed to be. We set an alarm to get us up in the morning; we rush out the door to be to work on time and then watch as the hours pass before we get to go home and spend time with our families and friends. We think about time when we need to be somewhere; we think about time when we would rather be somewhere else.

    We also tend to think about time when we're reminded that we need to set our clocks forward an hour in the spring and back as winter approaches. For those who have atomic clocks, even this isn't an issue as, in many cases, the clocks automatically reset themselves.

    Of course, there's always going to be a little bit of contemplation of how atomic clocks work. While we can read explanations of the cesium atom, the hydrogen and rubidium atoms and the ways in which they interact to determine time - while we can read the instruction manuals that come with atomic clocks and see reference to the ways in which some commercial atomic clocks are periodically corrected by GPS in order to ensure accuracy - there's little that fully helps many people to understand why such accuracy is really necessary.

     Ultimately, the concept of why accurate time keeping is important can be traced back hundreds of years. Long before the development of the atomic clock - as well as the development of nautical clocks and other ship clocks - it was determined that there needed to be some sort of international standard for time keeping.

    It was because of this need to set standards in time keeping that Greenwich Mean Time (GMT) were established. Prior to the 19th century, time was something that was determined merely by the sun. China, for example has one system of time that was independent from time in France, which was independent of time in Australia, which was independent of time within the United States.

    Before Greenwich Mean Time was accepted as an international standard, time keeping posed real challenges for growing industries. When shipments were to be made, ship captains had difficulties telling time because as they traveled east to west, the sun would shift in the sky; for them, telling time was a matter of determining location and, only being able to use the stars as a navigation tool, posed a number of additional challenges. Similarly, as railway transportation because increasingly common combined with the fact that most towns set their local time according to when the sun was at its apex, it became essential to determine a way to express time consistently.

    Ultimately, the standard for Greenwich Mean Time came about when in the 1880s representatives of nearly 30 nations came together to establish a means by which time could be measured accurately. During that convention, it was determined the Greenwich Meridian on which the Royal Observatory had determined the beginning and end of a 24 hours day and it was decided that maritime sea charts would be established based on the international time keeping standard.

    In order for those who captained ships to determine their location, longitudinal meridians were used. By consulting sea charts and having accurate nautical clocks on board, captains were better able to identify their location, chart their course and make progress toward reaching their destination when scheduled.

    Ultimately, being able to accurately tell time and location with the aid of nautical clocks and the Greenwich Meridian have had a dramatic impact on time keeping today. In addition to maintaining a schedule for shipments, Greenwich Mean Time allows international business and transportation to succeed and to continue to advance efficiencies.

    With Greenwich Mean Time - along with the developments that have been made for atomic clocks with greater accuracy - it is possible for business to be conducted between countries across the world; likewise, it is possible to consistently keep track of international flights as well as cargo shipments.

    In business and in transportation, time and timing are essential. It's for this reason that clocks have undergone a tremendous amount of change over time in order to ensure greater levels of accuracy. Understanding Greenwich Mean Time - even on a basic level - is something that can give a greater appreciation for the ways in which we are all connected. Even if international time is something that you only think about when you’re picking someone up at the airport, or flying off for a vacation, standard international time does impact us all.

Copyright © 2008 Andy Lipps

Andy Lipps