On Mon 2007-01-01T21:19:04 +0000, Ed Davies hath writ:
> Why does the "One sec at predicted intervals" line suddenly
> diverge in the early 2500's when the other lines seem to just
> be expanding in a sensible way?

Upon looking closer I see a 200 year periodicity in the plot.
I begin to suspect that rather than run a pseudorandom sequence of LOD
based on the power spectrum he instead took the past 2 centuries of
LOD variation around the linear trend and just kept repeating those
variations added to an ongoing linear trend.

I suspect that the divergence of the one line indicates that the LOD
has become long enough that 1 s can no longer keep up with the
divergence using whatever predicted interval he chose.  I suspect that
the chosen interval was every three months, for it is in about the
year 2500 that the LOD will require 4 leap seconds per year.

As for the other questions, McCarthy had been producing versions of this
plot since around 1999, but the published record of them is largely
in PowerPoint.  Dr. Tufte has provided postmortems of both  Challenger
and Columbia as testaments to how little that medium conveys.

Steve Allen                 <[EMAIL PROTECTED]>                WGS-84 (GPS)
UCO/Lick Observatory        Natural Sciences II, Room 165    Lat  +36.99858
University of California    Voice: +1 831 459 3046           Lng -122.06014
Santa Cruz, CA 95064        http://www.ucolick.org/~sla/     Hgt +250 m

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