In article ,
writes:

Ie: Can these very similar values all have a common origin--perhaps in the
mutual spin and tidal interactions of the Earth-Moon-Sun system? The usual
driver for mantle (and plate) motion is said to be due to the heat flow and
the local geochemistry of the Earth's interior, and of course the decay of
several radionuclides. Ie: Is this similarity between (1, 2) and (3)
merely a quirky coincidence? Or, over billions of years, have all three
processes achieved some mutual energetics 'partitioning' balance?

[[Mod. note -- It's a coincidence. -- jt]]

Earth core heating can be stated as an effect of Sun/Earth/Moon
gravity tidal effects.

That certainly plays a role. However, the Earth is heated by
radioactivity to a significant extent as well.

This effect is seen in comet core heating
as it passes near the sun. The core of the comet heats before
the surface does.

Even if it is true that the core heats up first, is it clear that it is
due to tidal heating?

So if tidal heating is real, the moon certainly be said to
effect the Earth core heating. And core heating then could be
said possibly altering mantle state.

Right, but the observation of the original poster is still a
coincidence.

Star to star tidal heating would then be seen as a dark matter
effect.

While it certainly exists to some degree, appreciable perhaps only
in close binary systems, it is unclear what this has to do with dark
matter.

Begging the question of observing dark matter in this
solar system.

You probably mean "ask" the question rather than "beg" the question.
("Begging the question" means answering a question in such a way that it
merely rephrases the original question.) So you are saying that if
star-to-star tidal heating is somehow responsible for effects which are
usually attributed to dark matter, then these might not be observable in
the Solar System? Note, though, that, depending on what it is, dark
matter might not be uniformly distributed, and lack of such observations
in the Solar System don't prove that it doesn't exist, much less prove
the star-to-star---tidal-heating hypothesis.