[LEAPSECS] alternative to smearing

[Zefram]

Preben Norager wrote:
>I see the proleptic gregorian calendar, represented by ISO 8601, and the
>GDs I propose, as a scientific way to settle the time of the incarnation.

It doesn't do that.  The birthdate of Jesus is a historical question,
and (as I noted) historians are pretty sure that AD 0 isn't the answer.
ISO 8601 takes no position on that question.

By promoting the use of AD year numbering *for the reasons that you
(Preben) do*, you are effectively endorsing *Dionysius Exiguus's*
position on this question.  If you get any more specific than he did,
for example if you state that Jesus was born specifically in AD 0, then
you're taking a position of your own on this question, a refinement of
Dionysius's position.

(For clarity: people who promote the use of AD year numbering for other
reasons are usually not taking a position on Jesus.  Especially so when
promoting it just because of the network effect.)

>Christmas shall be a yearly remembrance of the incarnation.

Going off on a bit of a tangent here: the season implied by the 25th of
December is inconsistent with that implied by the Biblical narrative of
Jesus's birth.  The date almost certainly arose from pre-existing nature
festivals associated with the winter solstice, perhaps specifically Sol
Invictus, into which Christians merged their Nativity celebrations.
So it's certainly not an anniversary date, and as a date for annual
commemoration it lacks distinctiveness to the Christian usage.

>                                                          Somehow I believe
>the proleptic gregorian calendar, and the GDs I propose, is the best way to
>settle the time of the incarnation, and unite east and west around the same
>calendar.

I don't see your GD system having any impact on religious calendar usage:
the churches are interested in years but not so much day counts.  In any
case, your religious objectives here are irrelevant to astronomy and to
the definitions of technical time scales.

Commemorating events in human history is pretty low down the list of
priorities for people defining time scales.  It does occasionally happen;
a recent example is the definition of Julian Sol (a Martian day count)
and matching epoch of the Darian calendar for Mars, which have their zero
slightly preceding the first telescopic observations of Mars.  (It's a
combination of commemoration with arranging for relevant historical
records to all have non-negative dates.)  But we really only do this
when we're otherwise completely devoid of a way to decide on an epoch.
We more often define time scales to maintain some kind of continuity
with existing time scales.  In any case, the need for reference points
to be precisely defined and accessible takes precedence over almost all
other considerations.

>                            But if you really care about the fundamental
>timescale of science and society,

Even for civil use, continuity and the network effect are very strong
considerations, which often take precedence over a desire to commemorate
some event.  This is a large part of why French Revolutionary year
numbering didn't catch on, for example.  Caring about civil timekeeping
therefore doesn't come with much opportunity to change where the year
zero lies.

>                                  then I don't see how you can ignore the
>time of the incarnation.

If we were to arbitrarily select a new epoch for civil timekeeping, in
a tabula rasa manner, then any epoch commemorating a religious figure
or event would actually be a pretty bad choice.  Any such epoch would
be terribly divisive.  (Look what happened with the religiously-derived
symbol of the Red Cross.)  It would be far better to pick an epoch of
more culturally-neutral significance, or at least one whose significance
inflames less passion.  The signing of the Metre Convention, as used as
a reference point by ISO 8601, would be a much better epoch, though some
would complain of it being slanted towards metrologists.

-zefram