There is astronomic evidence of vast stretches of mostly massless space on cosmically large scales known as Voids.
Under certain conditions, gravity can be repulsive (apparently, responsible for the increasingly rapid rate of universal expansion.)
Repulsive Gravity & The Big Bang | Brian Greene - YouTube
Is repulsive gravity considered a viable explanation for void production?
Does “Empty Space”, in fact, beget more empty space?
“Empty” space does in fact beget more empty space, due to the “repulsive gravity” effect you mention (also called “dark energy” or “the cosmological constant”), but you’d get vast intergalactic voids bordered by a “foam” of matter even without that. And in fact, dark energy (at least, in the simplest models, which we don’t know enough to be able to rule out) wouldn’t result in structure formation at all, just in uniformly stretching whatever structures you already have.
I’m a huge astronomy fan and this is the first time I’ve ever heard dark energy referred to as “repulsive gravity”.
Well, strictly speaking, the dark energy itself isn’t “repulsive gravity”, but the gravity generated by dark energy is repulsive. Just like you wouldn’t say that the Sun is attractive gravity, but it does have attractive gravity.
Anyway, that’s if it even is “dark energy”. That’s the currently-favored way to formulate it, as the result of normal gravity as we understand it generated by a substance we don’t much understand with very abnormal (from our experience) properties. But the math is equivalent to it being what used to be called “the cosmological constant”, which isn’t due to a substance per se but is just another term in the gravity equations, and which would genuinely be “a different kind of gravity”.
it had occurred to me the dual paradigm of Dark Matter and Dark Energy are, in fact, manifestations of the same phenomena…just on different parts of a spectrum of spacetime “viscocity”.
Intra-void spacetime may be thought to have what we perceive to be negative pressure: vaccuumier, than vaccuum.
Intra-galactic spacetime may, in contrast, be “thick as molasses”: spacetime not just full of matter, but the very properties like permeability and permittivity being altered.
Vacuum permeability - Wikipedia
Permittivity - Wikipedia
( viscocity/thickness being different than the warping/curvature of spacetime in the presence of matter)
Dark matter and dark energy being closely related phenomena is certainly a possibility. Them being completely unrelated is a possibility, too. We know next to nothing about the majority of the dark matter, and less than nothing about dark energy, so pretty much anything is fair game.
EDIT: The real question, with any new idea, is where can you go with it? Can you make any predictions about anything observable with this idea? Can you come up with a single, elegant mathematical framework that describes both, while being simpler than the sum of describing both separately? There’s nothing wrong with “Dude, what if…” speculation, but that’s the easy part of advancing science.
Viscosity. 