On Jan 12, 2006, at 12:36 AM, John Cowan wrote:
> No one, at least not on this list, is arguing for an alignment of the
> absurd leap hour proposal (henceforth ALHP) with DST changes.
I went rummaging through the ITU proposal and back as far as Torino.
Found this comment from a LEAPSECS thread on 28 July 2003:
>> > At Torino the proponents of omitting leap seconds supposed that the
>> > governments of the world might handle this situation using leap
>> hours
>> > introduced into civil time by occasionally omitting the annual
>> ``spring
>> > forward'' change to jump to summer/daylight time.
This particular quote originated with Steve Allen's excellent page:
http://www.ucolick.org/~sla/leapsecs/dutc.html
I couldn't find any explicit mention of this in the discussions at
Torino, but Steve must have gotten it somewhere - and as you say, not
from the list. It may be an opportune time for folks to reread the
presentations from Torino:
http://www.ien.it/luc/cesio/itu/ITU.shtml
For example, I found this interesting tidbit from the Russians:
"This is to inform you that to our opinion it is necessary to
preserve the status-quo of the UTC time scale."
Considering GLONASS is always trotted out as the only explicit
example of a system that fails to handle leap seconds, this seems
significant somehow.
More-or-less the entire text of the proposed change to ITU-R TF.460-6
is expressed here:
>> Operational rules
>>
>> (after 0000 UTC 21 December of the transition year)
>> 1 Tolerance
>>
>> The difference of UT1 from UTC should not exceed ±1h.
>> 2 Adjustments to UTC
>>
>> 2.1 Adjustments to the UTC time-scale should be made as
>> determined by the IERS to ensure that the time-scale remains
>> within the specified tolerances.
>> 2.2 The IERS should announce the introduction of an
>> adjustment to the UTC time-scale at least five years in advance.
>> At the time of the announcement the IERS should provide directions
>> regarding the details of the implementation of the adjustment.
>> 2.3 All operational rules and nomenclature prior to
>> 0000 UTC 21 December of the transition year given above no longer
>> apply.
>> NOTE 1 – The broadcast of DUT1 will be discontinued.
>> NOTE 2 – Predictions of the Earth’s rotation currently indicate
>> that such an adjustment would not be required for thousands of years.
Note the inaccurate and self-serving "thousands of years" that is
corrected to 500 years in the draft. There isn't the slightest
specification (or analysis) of how a leap hour might be implemented -
just an assumption that the IERS will persist indefinitely. We're
certainly aware that "all operational rules" are to be changed - but
what about the nomenclature? Imagine changing an ISO or SI standard
- preserving a trail of coherent nomenclature would be half the
document. And then, of course, the amazing fact that the document
simultaneously increases the importance of DUT1 by orders of
magnitude, while discontinuing its issuance. This "proposal" is not
only ill considered, it is simply - well - lazy and arrogant.
> We already have that repeated time sequence and gap in much of the
> world,
> and live with it. These repetitions would be no better and no worse;
> when a gap is present, the local sovereignty can omit the gap, but
> this
> is not a necessary feature of the proposal.
The point I was trying to make is that you can't simultaneously omit
the overlaps/gaps and preserve anything even vaguely resembling the
familiar relationship between our clocks and the solar day. It
doesn't matter whether we continue an international civil time system
or abandon it for local anarchy - people everywhere in the world
would have to deal with the repercussions. That the situation will
degrade slowly over a few hundred years before collapsing
catastrophically doesn't really seem to recommend the plan.
It may not sound like it, but I am willing to be convinced otherwise
- but you'll have to do a lot better than rivaling the scant length
of the ITU proposal. How about a detailed scenario of exactly how
you see this working for a couple of neighboring but distinct local
timezones? What is the precise mechanism that might be used?
The subtext of both your position and the "absurd leap hour proposal"
is that civil timekeeping is so trivial that everybody from barbers
to burghermeisters should be encouraged to make public policy - after
all, these aren't "important" scientific and technical issues.
Rather, civilian users deserve as good or better a timescale as the
technical users (who ultimately can take care of themselves).
> Historians already deal with the discontinuity between Julian and
> Gregorian calendars, which was similarly conducted in a decentralized
> fashion between 1582 and 1924.
That there was a global mess several hundred years in the past is not
a particularly good reason to generate another global mess several
hundred years in the future.
Aliens? Us? Is this one of your Earth jokes?
Rob Seaman
NOAO
Received on Thu Jan 12 2006 - 20:14:59 PST