Re: [LEAPSECS] "Universial" Time,"Terrestrial" Time -- time for new terminology?

From: Ed Davies <ls_at_EDAVIES.NILDRAM.CO.UK>
Date: Tue, 08 Jul 2003 16:46:43 +0100

Markus Kuhn wrote:

> A point that was made repeatedly at Torino is that the term "UT"
> traditionally meant in astronomy a time scale defined by the Earth's
> rotation, and that therefore a leap-second free uniform atomic time
> should not be called UTC, even if doing so would of course avoid the
> need to change the large number of national regulations that explicitely
> refer to "UTC" today.
> I understand that the term "Universal Time" was cooked up in the IAU in
> the 1920s, but does anyone know more details about the origin of and
> reasons for this curious choice of terminology?
> I always thought it was a rather odd selection of words:
> "Universal Time" is not linked in any way with the "Universe" as such.
> It is related to the position of the sun in a coordinate system that is
> attached to the crust of this particular piece of molten rock.
> ....

Yes, "pre-Copernican" is the expression which occurred to me.

UTC tracks the rotation of the Earth to +/-0.9 seconds. This new scale
(assuming leap hours were actually implemented) would do so to +/- 3600
seconds, or so. There's a difference in scale but not in principle so
the argument to get rid of the name UTC is not iron-clad.

It's hard enough to persuade people that GMT is dead without having
yet another time scale name to deal with. I think it's better to forget
what the letters once stood for and just accept that the name "UTC"
means the time scale which is the basis of civil time: the one you
add various offsets, in hours and sometimes minutes, to in order to
get local civil time.

For example, "ISO", though appearing to be an acronym, doesn't actually
stand for a sequence of words:

Received on Tue Jul 08 2003 - 08:50:23 PDT

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