Re: [LEAPSECS] Mechanism to provide tai-utc.dat locally

From: M. Warner Losh <imp_at_BSDIMP.COM>
Date: Thu, 28 Dec 2006 22:13:53 -0700 (MST)

In message: <20061229042407.GL13444_at_ccil.org>
            John Cowan <cowan_at_CCIL.ORG> writes:
: In this case there are really two questions: how much it would
: cost to loosen DUT1 but leave it bounded, and how much it would
: cost if it were only statistically, not absolutely, bounded.

We've accepted a statistical solution for the leap-day problem now for
about 500 years. There are minor variations, and over the next 10's
of thousands of years this simple solution may not prove workable (it
will be off by more than a day on the average in about 8,000 years if
nothing is done). Right now winter solstice can be off by over a day
from the mean either direction, yet over the long haul things average
out. There's no call for there to be leap days scheduled at the whim
of the astronomers anymore... Seems like a logical leap for leap
seconds to follow, if the costs aren't prohibitive. Chances are that
one person knows all the users of time that still need DUT1 to be less
than 1s.

One big area of change would be the time and frequency stations, like
WWV, since they currently broadcast DUT1, or variations of it. But
the correction they broadcast is good only to 100ms typically
(time-nuts_at_ have documented cases where it was worse than 100ms when
some national time lab didn't update the data transmitted when they
were supposed to), so maybe some other means of distribution is
necessary... And is 100ms really good enough?

Warner
Received on Thu Dec 28 2006 - 21:16:09 PST