The Greenwich Meridian

Don’t know what time it is?  Hardly surprising in Spring and Autumn.

Today is exactly one month before the United Kingdom ‘moves’ its clocks forward and enters British Summer Time; 1am (UTC) on Sunday 28th March 2010.  Is that date the same across the world?  One would think so because it makes life, especially international air transport, so much easier.

But no!  In fact the way that time zones are applied and changed for Daylight Saving is a complete hotch-potch.

In the United States of America, daylight saving starts at 2am on March 14th, 2010.  And just three years ago that start time would have been the first Sunday in April.  Changes were made in the US Energy Policy Act of 2005.

From this geographic site comes the following:

Other parts of the world observe Daylight Saving Time as well. While European nations have been taking advantage of the time change for decades, in 1996 the European Union (EU) standardized an EU-wide “summertime period.” The EU version of Daylight Saving Time runs from the last Sunday in March through the last Sunday in October. During the summer, Russia’s clocks are two hours ahead of standard time. During the winter, all 11 of the Russian time zones are an hour ahead of standard time. During the summer months, Russian clocks are advanced another hour ahead. With their high latitude, the two hours of Daylight Saving Time really helps to save daylight. In the southern hemisphere where summer comes in December, Daylight Saving Time is observed from October to March. Equatorial and tropical countries (lower latitudes) don’t observe Daylight Saving Time since the daylight hours are similar during every season, so there’s no advantage to moving clocks forward during the summer.

Of course, someone had to create a web-site to track all these various time zones and changes.  Here it is.

Last year, the BBC News website published an interesting article about the Greenwich Meridian aka The Prime Meridian.  The setting of the Prime Meridian was done just over 125 years ago, in October 1884.  When one thinks of the importance in having a standard meridian, both for time keeping and navigation, I would have guessed that it went back much further in time.

The other aspect that was news to me was that the conference had been convened at the request of the American President Chester Arthur.

From that BBC article:

Until the 19th Century, many countries and even individual towns kept their own local time based on the sun’s passage across the sky and there were no international rules governing when the day would start or finish.

Maps with multiple meridians were confusing

However, with the rapid expansion of the railways and communications networks during the 1850s and 1860s, setting a standard global time soon became essential.

“The world was in a very big mix-up,” explains Dr Avraham Ariel, author of Plotting the Globe. “People had lots of prime meridians. Earlier in Europe there were 20 prime meridians. The Russians had two or three, the Spanish had their own and so on.”

Thus that famous line in the grounds of the National Maritime Museum at Greenwich, London is not as old as many might have thought.

Prime Meridian, Greenwich

By Paul Handover

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