Re: [LEAPSECS] pedagogically barren?

From: Markus Kuhn <>
Date: Wed, 04 Jun 2003 10:40:09 +0100

Steve Allen wrote on 2003-06-03 20:41 UTC:
> My point was that I believe the current list of offered solutions are
> not wild enough. If the SRG had clout I would expect to see it
> persuading the Galileo system to adopt TI = UTC at the time of launch,
> and then I would expect to see them persuading the GPS maintainers to
> switch GPS time to match that Galileo TI as a part of the next GPS W1K
> rollover. Or I would expect to see them convincing Galileo to adopt
> GPS time. Otherwise I would like them to be explaining why these are
> not feasible.

It was my understanding that some of the proposals implied that the
long-term goal would be that all satellite navigation systems should
eventually aim at approximating TI as close as feasible with one of the
time scales they provide.

> If only PowerPoint presentations are posted in the absence of detailed
> written arguments and references to published discussions then the
> colloquium is pedagogically and archivally barren. Nobody who was not
> there can benefit from it.

I asked Ron Beard, and he said that there were no plans for written
post-proceedings of this meeting. I personally would have liked very
much to end up with a written book of everything that was presented and

> This is especially so if it means their garden sundials
> will diverge and their descendants will be handed a problem to solve.

Sundials diverge anyway thanks to the Equation of Time, and are shipped
with compenstation tables. I guess it could be argued that the move from
UTC to TI would merely add another term to the Equation of Time, if you
accept that most sundials are difficult to read more precisely than a
few minutes and that within that tolerance, UT1 should be predictable
for a couple of decades, if not centuries.

> > Just look at the sorry state of the use of SI
> > units in United States legislation to get the idea.

> We do use SI units.

While the international inch is indeed linked to the meter by a
reasonably round factor, and even shows up indirectly in a number of ISO
standards (e.g., inch-based threads and pipes), this can clearly not be
said for the US pound and the US gallon and units derived from these,
which are still required by US federal law to be present on consumer
packages. As long as it remains legal and even required in the US to
price goods per gallon or pound (units completely unrelated to the inch!),
and US congress continues to fail following its constitutional duty of
defining and enforcing a proper system of measurements for trade, the
use of SI units in the US must unfortunately, in my personal opinion, be
described as a rather sorry state. I understand that the inch is here to
stay for a long time because of established precision product standards,
but this is not the case for the US units of volume, weight, mass and
temperature, which could be abandoned trivially over night if there were
just a little bit of good will with regard to international
standardization. (I'm talking about commercial, not scientific practice.)


Markus Kuhn, Computer Lab, Univ of Cambridge, GB | __oo_O..O_oo__
Received on Wed Jun 04 2003 - 02:40:28 PDT

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