[time-nuts] Re: UTC

Chuck Harris cfharris at erols.com
Tue Jul 26 19:06:31 EDT 2005

Poul-Henning Kamp wrote:
> In message <4A4B4876-7D7F-4D81-AE31-26A757E7AA81 at noao.edu>, Rob Seaman writes:
>> Pop quiz!  What is the length of the day?  No tricks - no gimmicks.
>> Launch a tee-shirt to that guy in the last row.  Right you are!  A day on Earth is 23h 56m 4s.
> Now, for two t-shirts:
> Which fraction of the earths population would disagree with the answer that astronomer gave ?
> Right there in front: 99.999% sounds about right.

Now, for 3 t-shirts Poul, reread Rob's last paragraph, but this time with your blinders removed.

[-----Rob Seaman's last paragraph-----]
It is very telling that arguments such as PHK's always seem to be  based on solar time.  After all, the spinning Earth
forms a steady  clock relative to the fixed stars, not the Sun.  The length of the  day "really, truly" is 23h 56m 4s.
Why is this never pointed out?   Because it simply isn't so for most purposes.  A day in the life is a  solar day.  It
is the solar day our clocks should characterize.  That  the Earth's orbit is elliptical, its axis tipped, and that it is
  circled by the Moon simply underscore the need for civil time to  follow mean solar time and thus bring clarity to our
timekeeping.  It  is precisely the overwhelming dominance of the Sun in our everyday  lives that illuminates the clear
choice of basing civil time on solar  time.  It is just as wrong for the precision timing community to  embrace the
split second (but growing) errors of raw TAI as it would  be to permit the nearly four minute daily error that sidereal
clocks  would impose on our lives.
[-----Rob Seaman's last paragraph-----]

You can agree to disagree, but Rob was using the 23h 56m 4s sidereal day as a parable, not as an actual
suggestion that we all abandon solar/seasonal time.

Neither of you is as dumb as you think the other to be.


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