[ntp:questions] A Suggestion For Abolishing the Leap Second

jlevine jlevine at boulder.nist.gov
Fri Jun 1 13:47:07 UTC 2007


Hello,
   The proposal to incorporate leap seconds by changing the length of
the
second was tried before in the early days of atomic time. It was not a
very
workable idea then and it would be even more difficult to implement
now.
  In the first place, the unit of frequency plays a central role in
precision
measurements and fundamental constants -- much more fundamental than
the unit of time. If the time services distributed a non-SI frequency
then
all frequency calibrations would become much more difficult and
ambiguous.
It was this difficulty that produced the current system from the
previous system
where the definition of frequency was periodically adjusted. You can
see these
difficulties if you look back at the various calibration experiments
in the early
1970s, just before the current system was adopted.
   In the second place, there are many, many stand-alone frequency-
sensitive
devices, and they are not able to change their internal frequency. For
example,
if a cell site had to remain on time, then its internal clock would
have to change
frequency whereas the zilliions of cell phones that were connected
would have
no easy way of following. The same thing holds for wall clocks, etc.
    This is not to suggest that the current system has no hassles --
it has lots
of them and they are only going to get worse as the interval between
leap
seconds decreases. This decrease in the interval between leap seconds
is
predicted by all contemporary models of the astronomical effects that
define UT1.
    To a great extent, where you stand on this question depends on
where you
sit, and the characterisitc of any compromise solution is that
everybody will be
at least a little bit unhappy.

Judah Levine
Time and Frequency Division
NIST Boulder




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