Saturday, November 03, 2007

Universal, Standard, Daylight Savings and Railroad Time


Before the introduction of standard time, cities set their official clocks according to the local position of the sun. Then inventions came in, the steam engine, the telegraph, and rail travel, which made it possible to travel fast enough over long distances to require almost constant re-setting of timepieces, as a train progressed in its daily run through several towns. Standard time, where all clocks in a large region are set to the same time, was established to solve this problem. Chronometers or telegraphy were used to synchronize these clocks.

Standard time, as originally proposed by Sir Sandford Fleming in 1879, divided the world into twenty-four time zones, each one covering exactly 15 degrees of longitude. The local time at the Royal Greenwich Observatory in Greenwich, England was chosen as standard at the 1884 International Meridian Conference, leading to the widespread use of Greenwich Mean Time in order to set local clocks.

Charles F. Dowd proposed in 1870 (after consulting railroad officials in 1869) that American railroads adopt four standard time zones. After further discussion among themselves, American and Canadian railroads adopted five standard time zones on November 18, 1883. Newspapers referred to that day as "the Day of Two Noons." There was no legislative enactment or ruling: the railroads simply adopted a five zone system encompassing North America from Nova Scotia to California, and assumed the public would follow.

The American Railway Association, devised their own system, which had irregular zone boundaries which followed then-existing boundaries of different lines, partly in order to head off government action which might have been inconvenient to their operations. Most people simply accepted the new time, but a number of cities and counties refused to accept "railroad time", which, after all, had not been made law.

In one Iowa Supreme Court case, the owner of a saloon argued that he operated by local (sun) time, not "railroad time," and so he had not violated laws about closing time. Standard time remained a local matter until 1918, when it was made law as part of the introduction of daylight saving.

It gets even more complicated than this, if this isn't complicated enough! Astronomers have preferred observing meridian crossings of stars over observations of the Sun, because these are more accurate. Nowadays, Universal Time, in relation to International Atomic Time (TAI), is determined by Very Long Baseline Interferometry (VLBI) observations of distant quasars, a method which has an accuracy of micro-seconds.

In 1928 the term Universal Time was adopted internationally as a more precise term than Greenwich Mean Time, because the GMT could refer to either an astronomical day starting at noon or a civil day starting at midnight. However, the term Greenwich Mean Time persists in common usage to this day in reference to civil timekeeping.

And if your a real Time fanatic, check out: Ephemeris Time, which has since been replaced by Terrestrial Time (TT) and then, there's even Barycentric Dynamical Time (TDB)!

Spring Forward, Fall Back.
And tonight's the night to Fall Back!

Now excuse me, but it's time for me to head to Portland, Oregon and some serious Christmas fabric shopping at Fabric Depot. I'm sure you've all noticed that Christmas started in September this year. Must be part of that 'Fall Back' in time business ;)

3 comments:

  1. Our stores started early this year with Christmas as well - before Halloween! I hate changing my clocks - I get too set in my ways. My sister uses all these different times as an excuse - since time is a random made up thing - she can just show up whenever she feels like it rather than somebody else's time.

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  2. I don't mind falling back. It's a difficult adjustment to spring forward in the Spring. I love my sleep!

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  3. Well here in NH the stores started with the Christmas items and decorations in October! thanks for the info on the time change..fall back oh yeah! more time to sleep or adjust..hopefully not be late...hehehe.

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Michele Bilyeu blogs "With Heart and Hands" as she journeys between Douglas, Alaska and Salem, Oregon.