'Darla' spake thusly:

I'm somewhat amazed by the interpretation of relativity that includes
"gravitation is not a force".

Yeah, especially when subjected to the ultimate 'litmus test' that
requires explaining the literal *mechanism* that powers the most
energetic gravitational processes in nature, super/hypernovae and
quasars.

...it still puzzles me that any rational being would accept that she
or he is made of matter with mass, and that anything but a force of some
kind is keeping her or his mass from floating away.

Yeah, "geometry" doesn't cut it.

If we keep in mind that the quark-antiquark pairs and the energy they
produce actually do comprise what humans call "space",

Well hell, maybe you wasn't around the past few years when the subject
was cussed and dis-cussed, viewed and re-viewed at great length here
with Painius. The 'substance' or 'matrix' of space had come to be
called by Painius the sub-Planck energy domain (or SPED), its
wavelength-state or 'granularity' residing below the Planck length,
below our sensory and EM resolution.. thus making it seem 'void' or
'nothing' to our sense-based logic. Yet it terms of its sheer energy
density, it comprizes the great bulk of 'What Is'. Matter, residing on
'this side' of the Planck line, presents the very *lowest* energy (and
longest wavelength) state of the spatial medium. The 'other side', the
SPED, obeys the maxim that the shorter the wave the higher the energy.
Its energy density (or energy equivalence) eclipses nuclear on the
scale that nuclear eclipses chemical. Painius used the whimsical
expression "E=mc^3", not meant as a literal equation but as a graphic
to emphasize this extreme energy density of the perceived 'void'. Your
cutish term "quark-antiquark pairs" would be the the equivalent of
Painius' SPED.

...then we may discover
that it is the pressure of "space itself" that produces the movement of the
pairs {the SPED} toward matter.

Yep, the stupendously powerful gravitation driving super/hypernovae
and quasars testifies to it. It testifies to the spatial medium being
under a hyperpressure state that exceeds degeneracy pressure of the
atomic nucleus. It's the only explanation that passes the 'SHQ litmus
test'.The core of *every* atomic nucleus presents the _lowest_
pressure state.to the SPED.

As always, it is an imbalance that produces this movement from the great
density of the QM energy to the less dense material particles.

Again, correctomente. It is the *pressure differential* between the
core of every nucleus and the pressure of space itself that drives the
accelerating flow whose effect we call gravity... and as a bonus,
nonchalantly solves unification of gravity and the SNF.

Of course at this point come the yowls and howls of the objectors,
with the 'Roach Motel' issue. "Where does the stuff go when it's
ingested through the nucleus?"

Indeed, where? Where does the Big Bang 'come from'? What strange
nonlocal, inverted realm is the 'ground state' common to both the BB
and gravitation? To declare the Flowing-Space model of gravity invalid
because it doesn't answer "where" the stuff goes is to declare the BB
invalid because it doesn't answer where the stuff comes from.

So, as with the BB, i'll just accept that gravity is exactly what it
appears to be and behaves as-- the pressure-driven, accelerating,
"reverse starburst" flow of space into matter, with any mass
synonymous with flow sink or pressure drain.