Take an extra second to reflect on 2005
- From: alan@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx (Alan)
- Date: Tue, 27 Dec 2005 13:11 +0000 (GMT Standard Time)
http://www.knoxstudio.com/shns/story.cfm?pk=LEAPSECOND-12-26-05&cat=II
By LEE BOWMAN
Scripps Howard News Service
December 26, 2005
- If 2005 is disappearing too fast for you, just hold on for a second, because
this year you have an extra second to pause and reflect on the year before the
ball drops and the calendar flips New Year's Eve.
Yep, it's a leap second moment, one of those rare occasions when clocks around
the world take a stutter step in order to conform with the Earth's wobbly,
gradually slowing spin.
But don't count on having many extra moments in the future, because there's a
movement in the telecommunications field to do away with leap seconds as early
as 2007.
In a 24/7 world, leap seconds that adjust the timekeeping of atomic clocks to
the time based on the rising and setting of the sun are viewed by many
technocrats as a nuisance, perhaps even a danger.
Atomic time, based on the radiation frequency of the cesium-133 atom, has been
around since the 1950s. Timekeeping based on the Earth's rotation goes back
thousands of years and is classically upheld by the Royal Observatory in
Greenwich, England, where, by the way, the extra second is formally marked.
The trouble is, atomic clocks are so accurate, they can go for 3 million years
without losing a second. Earth's rotation, it turns out, is somewhat less
reliable. That's because the daily tidal influence of the moon's gravity acts as
a brake on the spin.
When international agreement was reached on Co-coordinated Universal Time (UTC)
in 1972, scientists figured that regular leap seconds would need to be added
every 18 months to keep the two systems in sync.
Instead, the International Earth Rotation and Reference Systems Service based in
Frankfort, Germany, has had to request only 22 leap seconds, coming on either
June 30 or Dec. 31, since 1972, with the last extra second tacked on back in
1998. But over the long-haul, scientists expect that the slowing of the rotation
will gradually increase over thousands of years, requiring even more frequent
corrections to atomic time.
This is all too random for software programmers and others in electronics
industries where a 61-second minute doesn't compute, literally. There have been
glitches ranging from Global Positioning Satellite receivers displaying the time
as 62 o'clock to broadcast services automatic DJs running errant tapes.
Citing those problems and the concern that things like air traffic control
systems might be compromised by leap seconds, the U.S. government two years ago
proposed to the International Telecommunications Union that leap seconds be
abolished.
That plan was briefly discussed at meeting of the ITU in Switzerland last month,
but delegates agreed to put off any decision until at least next year.
The notion has been officially opposed by a number of groups involved in
astronomy and Earth observation, including the Royal Astronomical Society. They
argue that disconnecting universal time from solar time is simply shifting a
technological problem from one group to another.
Among other things, the change could cost observatories many thousands of
dollars to regularly reprogram telescopes software to hit the right point in the
sky on a given night.
Ultimately, without leap seconds, clocks would have no relevance to day and
night, critics complain. "It could one day mean it says noon on our watches, but
it's midnight outside," said Jonathan Betts, a curator of horology at the
Greenwich Observatory.
On the other hand, with seven years and oodles of electronics manufacturing
having passed since the last leap second, a lot of electronics engineers are
holding their breath to see how the newer gear copes with a 61-second minute.
Dennis McCarthy, who has been working on the leap-second problem as Director of
Time at the U.S. Naval Observatory in Washington for more than a decade and
drafted the proposal presented to the ITU, argues that the drift between
celestial and atomic time isn't that radical. "It's a two-minute problem over
100 years," he said.
The U.S. plan actually would keep the sun and clocks generally in sync by adding
a "leap hour" every 500 or 600 years as the extra seconds pile up, a switch more
acceptable to technology that copes with the spring forward, fall back
adjustment for Daylight Saving Time each year.
For now, says Michael Hapgood, secretary of the RAS, "there are a lot of good
people already involved in the debate. We need them to work together to improve
current timekeeping for everyone's benefit, and not just for one group."
On the Net: www.usno.navy.mil
www.ras.org.uk
tf.nist.gov/general/leaps.htm
I object strongly to the American plan. Greenwich mean time has nothing to do
with the Yanks. Greenwich Mean Time is the time at Greenwich and it was us who
adopted it as our standard and who do these Yanks think they are, messing about
with our time? I object very strongly. I shall continue adjusting all my clocks
by the extra second in accordance with The Royal Observatory.
I am going to complain to the Queen. I am going to complain to my MP. I am going
to protest in this newsgroup. Dennis McCarthy must be some kind of anarchist to
be causing an international incident like this. I do hope the CIA are monitoring
his activities. I do hope they lock him up and throw away the key.
Alan
http://www.veloceraptor.free-online.co.uk/enigma.html
http://veloceraptor.blogspot.com/
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