trading amplitude for scheduling (was Re: [LEAPSECS] leap seconds in video art)

From: Rob Seaman <seaman_at_noao.edu>
Date: Thu, 3 Aug 2006 11:21:32 -0700

Brian Garrett wrote:

> the mini-lectures did imply that leap seconds compensate for
> secular deceleration of the earth rather than seasonally
> accumulated differences between UTC and UT1.

To the extent that I understand the point you are aiming for, this
statement conflates two issues:

        1) that the long term secular deceleration is only perceptible as a
baseline trend hidden beneath large amplitude, short period, effects,
and

        2) that leap seconds aren't the result of new slowing (or speeding
up), they are the result of cumulative clock corrections required due
to previous slowing.

I agree with both, but just because we're bleeding off the cumulative
terms seasonally (which I take to mean "over short term periods of
whatever duration and connected to whatever physical cause"), it
doesn't mean the secular trend is not pertinent. We're required to
synchronize two clocks whose rates differ. We cannot adjust the
rates ourselves and they are slowly drifting further out of step due
to the inconvenience of physical reality (or a "charming fact of life
in the solar system" as someone said).

The impact of the short term effects isn't to either increase or
decrease the net number of leap seconds, it's to play bloody hell
with their scheduling. I perceive this as a fact of life that should
be accommodated (and that serves as job security for folks like
Daniel Gambis). Others perceive this as an awkward reality to
attempt to ignore (although the ALHP will result in twice as many
leap seconds than otherwise when the first leap hour is announced in
2606 by Obi Wan Gambis).

The charm of Felicity's work is in the implied distinction between
the trees of the experts and the forests of the public.

Rob Seaman
NOAO
Received on Thu Aug 03 2006 - 11:22:21 PDT