Posts Tagged ‘Coordinated Universal Time’

I have all sorts of philosophical anxieties about disconnecting ‘official time’ from the ‘real time’ that we experience through the rising of the sun and the arc of the stars – I’ll try to post about these anxieties another day.

But there is a huge historical irony in the fact that Greenwich Mean Time will most likely be replaced by Coordinated Universal Time, which is determined by the International Bureau of Weights and Measures (BIPM) in Paris, a city that lost its own right to determine the world’s time to London many years ago.

In case you missed the details of the recent recommendations of the International Telecommunications Union (ITU), Tony Todd reports:

Greenwich Mean Time (GMT) may be consigned to history as increasingly complex communications technologies require a more accurate system of measuring the time.

International clocks are set according to Greenwich Mean Time, a system that measures time against the rotation of the earth according to the movement of the sun over a meridian (north-south) line that goes through the Greenwich district of London.

The problem for the scientific community is that the earth’s rotation is not constant: it slows down by about a second every year.

US Navy scientist Ronald Beard chaired the working group at the ITU in Geneva which that last week recommended GMT be scrapped as the global time standard.

He told FRANCE 24 on Tuesday: “GMT has been recognised as flawed by scientists since the 1920s, and since the introduction of Coordinated Universal Time (UTC) [measured by highly accurate atomic clocks] in 1972 it has effectively been obsolete.”

UTC solved the problem of earth’s uneven rotation by adding the occasional “leap second” at the end of certain years to keep GMT accurate.

But this piecemeal system is no longer suited to the increasingly sophisticated communications technology and the needs of the scientific community.

“With the development of satellite navigation systems, the internet and mobile phones, timekeeping needs to be accurate to within a thousandth of a second,” said Beard. “It is now more important than ever that this should be done on a continual timescale.”

In effect, what the ITU is proposing is that atomic clocks should govern world time. Instead of using the GMT system and adding leap seconds, time should be allowed to be measured without interruption.

Beard explained that large-scale changes could be made (very occasionally) so that, for example, in 40,000 years time people would not be eating their lunch in the sunshine at “midnight”.

Do you notice that phrase: “Time should be allowed to be measured without interruption”? As if the passage of time itself (the spinning of the earth, the passing of days, the passage of seasons) somehow gets in the way of ‘official’ time – the time on the dial of an atomic clock.

OK, I admit it. As an Englishman I reel at the thought that the ultimate reference point for everything that happens, and in effect for the whole of human history, should be a memorandum issued by a committee in Paris, rather than a line carved into the ground in London.

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