[ntp:questions] Re: no more leap seconds?

Rich Schmidt res at tuttle.usno.navy.mil
Wed Aug 10 20:53:03 UTC 2005

The word is "insidious", and as you surely do not accuse the
"governement" of laying a trap, or of having harmful but enticing
designs, you must be saying there is something with a "gradual and
cumulative effect", which is of course the variations in the Earth's
rotation leading to the need to leap UTC back to UT1 end of this year!

More than five years ago, international groups of scientists began
looking at formal recommendations to replace leap seconds, in order to
reduce the frequency of discontinuities in the UTC timescale. The work
has not been "done in secret" but yes, "Good Morning America" has not
yet reported on it. The most interested body has been the ITU
(International Telecommunications Union), and at a meeting in Torino in
May, 2003 the ITU-R Study Group 7 presented proposals which were not
accepted in fully by attendees who did not want to see UTC changed
...at least for the next 17 years.

Then in Oct. 2004 the US Working Group 7A submitted a proposal to
eliminate  leap seconds in Dec. 2007, and to introduce leap hours, the
first of which would not be needed for about 600 years (based on
current analysis of historical observations of the Earth's rotation
rate).  As with leap seconds, leap hours would not be regularly
scheduled but only as needed, and 600 years would almost give enough
time for programmers of the world to work leap seconds into their code.

This proposal was rejected by Great Britain for interesting reasons,
and so there is not currently an active ITU recommendation on the
table. The US ITU proposal is not an official position of the US
government, of DoD, GPS, etc.
If the ITU-R WG does present a UTC change proposal in November, it
first would have to be endorsed by the ITU at large.

There is an IAU (International Astronomical Union) Working Group on the
subject which will report at Prague in August next year, but the IAU
has thus far not adopted a uniform opinion of monkeying with UTC and is
not likely to
support the end of leap seconds.

I am indebted to Dr. P.K. Seidelmann, U. Va., for the above reports.
Rich Schmidt USNO

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