u/EngineWeak2953

I am wondering about the current boundaries of standard cosmology and whether we are hitting a conceptual wall with certain phenomena. I understand how the Friedmann and GR equations model the universe, but don't they rely on parameters (like Lambda) that currently act as placeholders for physical mechanisms we have yet to identify?

Mainstream hypotheses focus heavily on internal sources (i.e. undiscovered particles for dark matter or vacuum energy for dark energy). But what if the source is external to our universe? Could a 5D bulk scenario, where gravitational influence from neighboring branes be the real cause of these observed effects (like flat galaxy rotation and accelerated expansion)?

I'd love to understand the current theoretical or observational constraints that rule out or disfavor these 5D bulk and branes compared to the standard, internal particle/energy hypotheses.

Just put a conceptual preprint on ResearchGate and want to check if the basic physical intuition makes sense or breaks GR immediately.

Instead of adding new dark particles or changing Einstein/Friedmann equations to fix the Hubble tension or the KBC void, what if the universe is simply an open subsystem?

Think of a 5D brane-world where nearby cosmic branches evolve and collapse. This background chaos would create a permanent, long-wavelength gravitational-wave background.

Through this lens, dark energy isn't a vacuum energy; it's the large-scale repulsive pushing force (environmental forcing) of that background. Moreover, dark matter isn't a particle; galactic rotation curves are just ordinary matter tracking fossilized curvature dents left on our spacetime by old shockwaves from neighboring branch collapses. And finally, voids like KBC are just nodes of destructive interference where these background waves cancel out.

The paper outlines some falsifiable signatures like orientation-dependent correlations in galaxy distributions for future surveys.

Where does this logic immediately clash with current cosmological data? Looking for honest critique on the physics.