[LEAPSECS] fb/meta join the leap second haters

[Steve Allen]

On Tue 2022-07-26T20:42:03-0400 Brooks Harris hath writ:
> Can anyone elaborate on what these 'decadal variations' may be?

What they are is power in the spectrum of LOD at periods of decades
that has been visible in the relatively good data from the past two
centuries and which contributed to the inclusion of "non-gravitational"
terms in the planetary theories of Newcomb and the lunar theories
of Hill and Brown.

Why they happen is harder to say since they probably originate in
the weather of the core of the earth, but maybe not.

See this Journees 2019 paper saying it may be crustal motion and ice
https://syrte.obspm.fr/astro/journees2019/journees_pdf/SessionIV_2/SIDORENKOV_Nikolay.pdf

Also in there that the earth had been getting less oblate, more spherical,
through around year 2000 but maybe now is getting more oblate
https://syrte.obspm.fr/astro/journees2019/journees_pdf/SessionIV_1/LIU_JiaCheng.pdf

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Steve Allen                    <sla at ucolick.org>              WGS-84 (GPS)
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