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Old October 30th 17, 11:38 PM posted to sci.astro.amateur
Gerald Kelleher
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Default Time and timekeeping

On Friday, October 27, 2017 at 1:50:55 PM UTC+1, Martin Brown wrote:


Our atomic clocks now maintain insane accuracy such that the seasonal
change in the moment of inertia of the Earth as the leaves fall from
northern hemisphere trees is detectable in the discreprancy between
(atomic) terrestrial dynamical time and the rotation of the Earth.


I am sure this entertains those who know no better but if things were normal we would be discussing the real variations which arise as a separate surface rotation throughout the planet's orbit.

The daylight side of the polar day is now well established as that location turns solely in response to the planet's orbital motion and, of course, turns parallel to the orbital plane -

https://www.usap.gov/videoclipsandmaps/spwebcam.cfm

The Equation of Time is a global correction therefore there are no hemispherical components as the accelerating and decelerating responses found in the orbital surface rotation show up in the varying length of each noon irrespective of location on the planet where the Sun comes into view each weekday.

Isolating daily and orbital surface rotations is a quest but it doesn't rely on falling leaves, it does have components like the largest single weather event on the planet like Arctic sea ice evolution so I face no real competition in terms of cause and effect in this matter.