Is Gravity Fundamental? A Physical Interpretation of the Cosmological Constant Through Black Hole Cosmology

Recent decades have established that gravity may be emergent rather than fundamental. Jacobson derived Einstein’s equations from thermodynamic principles, Verlinde proposed entropic gravity, and Padmanabhan developed extensive thermodynamic interpretations. However, these frameworks lack a concrete physical mechanism for the cosmological constant Λ—the deepest unsolved problem in physics, with a 10120 discrepancy between observation and quantum field theory. This paper provides a physical interpretation of Λ by combining emergent gravity with black hole cosmology. The central hypothesis is that the universe exists within a black hole in a parent universe, where steady matter infall from the exterior manifests as constant energy density ρΛ in the interior, providing a concrete, order-of-magnitude physical pathway. In weak-field and homogeneous limits, dynamics are governed by ∇2Φ=4πG(ρm−2ρΛ), where ρΛ=Λc2/(8πG), demonstrating gravity as an interference effect. This framework is mathematically equivalent to ΛCDM, reproducing H0=67.43 km/s/Mpc, q0=−0.549, and ztrans=0.67. Rather than solving cosmological paradoxes, this interpretation naturalizes them through open-system energetics and inevitable transition dynamics, offering potentially testable implications while remaining equivalent to ΛCDM at the background level.