Every gravitationally bound system in nature orbits something more massive — the Moon orbits the Earth, the Earth orbits the Sun, the Sun orbits the galactic center, galaxy clusters stream within superclusters. This universal gravitational hierarchy has no known terminus. We ask: what does the universe itself orbit within? We propose: its own collapsed edges. We present the Self-Boundary Black Hole Shell hypothesis. After the Big Bang, the outermost regions of the expanding universe — where expansion velocity was highest and local density lowest — cooled and decoupled from radiation first, forming the first stars and black holes ~200–500 Myr earlier than interior matter. Over billions of years, these edge black holes merged hierarchically into a massive shell of collapsed matter at the boundary of the observable universe. This single physical population produces both dark matter (the gravitational mass of the shell, ~10²⁴ M☉) and dark energy (the geometric effect of the radial density gradient via the Lemaître-Tolman-Bondi mechanism — no cosmological constant required). Key results: Unifies dark matter and dark energy from one mechanism (Λ = 0) Explains JWST discoveries of unexpectedly massive black holes at z > 10 as the inner surface of the shell Predicts time-varying w(z) ≠ −1, consistent with DESI 2024 results Predicts a gravitational wave background from shell mergers testable by NANOGrav and LISA Predicts radial gradients in galaxy properties at high redshift Completes a self-sustaining cycle: expansion → edge-aging → shell formation → deceleration → collapse → bounce → expansion No extra dimensions, no unknown particles, no cosmological constant — only black holes and general relativity. v2 (March 2026): Major revision. Paper restructured to focus exclusively on the Self-Boundary Black Hole Shell hypothesis. Removed speculative dimensional and external-field models from v1. Now 22 pages with 5 testable predictions.
Bhanu Chandar Kurella (Mon,) studied this question.