The Black Hole Universe, Part I

Enrique Gaztanaga*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


The original Friedmann (1922) and Lemaitre (1927) cosmological model corresponds to a classical solution of General Relativity (GR), with the same uniform (FLRW) metric as the standard cosmology, but bounded to a sphere of radius R and empty space outside. We study the junction conditions for R to show that a co-moving observer, like us, located anywhere inside R, measures the same background and has the same past light-cone as an observer in an infinite FLRW with the same density. We also estimate the mass M inside R and show that in the observed universe (Formula presented.) GM, which corresponds to a Black Hole Universe (BHU). We argue that this original Friedmann–Lemaitre model can explain the observed cosmic acceleration without the need of Dark Energy, because (Formula presented.) acts like a cosmological constant (Formula presented.). The same solution can describe the interior of a stellar or galactic BHs. In co-moving coordinates the BHU is expanding while in physical or proper coordinates it is asymptotically static. Such frame duality corresponds to a simple Lorentz transformation. The BHU therefore provides a physical BH solution with an asymptotically deSitter metric interior that merges into a Schwarzschild metric exterior without discontinuities.

Original languageEnglish
Article number1849
Number of pages22
Issue number9
Publication statusPublished - 5 Sept 2022


  • black holes
  • cosmology
  • dark energy
  • general relativity

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