[LEAPSECS] WP7A status and Re: clinical evidence about time and sun

Rob Seaman seaman at noao.edu
Thu Dec 18 17:09:48 EST 2008

I should make the aside that these debates seem to pop up "like
clockwork" every year around this time :-)

Regardless of everyone's entrenched positions, a most Happy New Year!

On Dec 18, 2008, at 2:46 PM, John Cowan wrote:

> I'm pointing out that we are *already* doing that when establishing

> local time.

No. It is different in kind to layer local standard time on top of a
UTC that is kept calibrated with respect to an external standard (the
Earth), than it is to attempt to use local standard time itself to
perform this calibration.

> Mean solar time is very important for certain purposes. So is

> moonphase,

> but I don't hear you howling against the Gregorian calendar and

> demanding

> the immediate imposition of the Jewish (or Babylonian or Chinese)

> calendar.

We are governed by many natural cycles. The diurnal cycle is clearly

My college logic text is at home. What is the fallacy called that
condemns me for arguments I've never made? No, indeed, I've never
howled about any of the problems weirwolves might have with keeping
track of the full moon - even though, very significantly, this is an
astronomical object.

If mean solar time doesn't matter, consider the gedanken experiment of
the ITU proposing we redefine the day to be 100,000 SI seconds, for
the sake of the obvious "convenience" this would bring. Why would
this be unacceptable?

> Actual plan: Switch to DST and double DST when the difference between

> mean solar time and local time becomes embarrassingly large. (And if

> Urumqi isn't embarrassed, why should Washington be?)

A) Does this really amount to a "plan" wherever you work?

B) I'll refrain from speculating about what it would take to embarrass
Washington. There are some other, rather higher priority, items that
I would have thought might have done so recently.

C) By attempting to handle the situation this way, historical
timekeeping (past and future) becomes far more of a fiction than the
simple requirement of having to keep track of a list of prior leap
seconds or predictions of future such.


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