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Scientists are delaying the start of 2006 by a leap
second. |
Get ready for a minute with 61 seconds. Scientists are delaying the
start of 2006 by the first "leap second" in
seven years, a timing tweak meant to make up for changes in the Earth's
rotation.
The adjustment will be carried out by sticking an extra second into
atomic clocks worldwide at the stroke of midnight Coordinated Universal
Time, the widely adopted international standard, the U.S. National
Institute of Standards and Technology said.
"Enjoy New Year's Eve a second longer," the institute said in an
explanatory notice. "You can toot your horn an extra second this year."
Coordinated Universal Time coincides with winter time in London. On the
U.S. East Coast, the extra second occurs just before 7 p.m. on New Year's
Eve. Atomic clocks at that moment will read 23:59:60 before rolling over
to all zeros.
A leap second is added to keep uniform timekeeping within 0.9 second of
the Earth's rotational time, which can speed up or slow down because of
many factors, including ocean tides. The first leap second was added on
June 30, 1972, according to NIST.
Since 1999 until recently, the two time standards have been in close
enough synch to escape any need to add a leap second, NIST said.
Although it is possible to have a negative leap second -- that is, a
second deducted from Coordinated Universal Time -- so far all have been
add-ons, reflecting the Earth's general slowing trend due to tidal
braking.
Deciding when to introduce a leap second is the responsibility of the
International Earth Rotation and Reference Systems Service. Under an
international pact, the preference for leap seconds is December 31 or June
30.
Precise time measurements are needed for high-speed communications
systems among other modern technologies.
(Agencies) |
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