On 2/8/2011 6:42 AM, Tony Finch wrote:
On Mon, 7 Feb 2011, Rob Seaman wrote:
Tony Finch wrote:
the whole point of universal time is that it's the default timscale
for civil use and only specialists should need anything else.
Stephen should add this to the consensus building list.
Does that mean that you agree that its very tight coupling to earth
rotation is a historical artefact rather than a necessary feature?
i.e. "whole point" or "main point"?
Tony (being argumentative).
From a historical point of view, the whole point of universal time was
to serve as a basis
of standard time zones, which in turn facilitated commerce (especially
the forms of
commerce involving railroads, which crossed time zones fairly often, and
crossed informal
local time domains very frequently). Interestingly, universal time was
adopted about the
same time electromagnetic dissemination of time scales became possible.
So universal time was adopted because people in industrialized nations
didn't want to
reset their watches too often as they traveled, and when they did, they
wanted it to be
easy; change it by a whole hour. Furthermore they wanted the ease of
receiving the
correct time by telegraph rather than having to set up some local
structure to measure
solar time.
A secular change to civil time that would be perceptible without the aid
of a clock has
never been introduced, so whether tight long-term coupling between earth
rotation
is a historical artifact or necessary feature has never been tested.
Gerry Ashton
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