[LEAPSECS] LEAPSECS Digest, Vol 45, Issue 1

[Steve Allen]

On Fri 2010-09-03T17:45:34 +0100, Zefram hath writ:

> I don't think an official realisation of GMT is required in order

> for GMT to meaningfully exist.


That means it cannot be a precision time scale, for there is
no authority to define a single realization.

What the ITU-R is righly tasked to do is to specify a time scale to be
used in broadcasts, and that does need to be a precision time scale,
so that time scale needs a definition by an authority.


> Does anyone have relevant historical documentation on the philosophical

> definition of GMT?


GMT is what time it was at the RGO meridian circle as interpolated
from moment to moment by the best clock they had.
It did not exist in any form prior to 1675.
In response to the need to synchronize trans-oceanic telegraphy
and as a result of a diplomatic coup hosted by the United States
GMT became the basis for worldwide time.

The extent to which local civil time needs to be a precision time
scale is a different question, and the ITU-R has no direct authority
over that.  What we're going to see is whether the ITU-R points
jurisdictions toward a greater understanding of the need to be careful
about specifying time, or whether we are seeing another diplomatic
coup in progress.

--
Steve Allen                 <sla at ucolick.org>                WGS-84 (GPS)
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