Chaisson's Ξ¦_m metric β power per unit mass (erg sβ»ΒΉ gβ»ΒΉ) β across the cosmic hierarchy. Where does a black hole ergosphere fall on the ladder of complexity?
This tool visualises Eric J. Chaisson's Free Energy Rate Density (FERD, or Ξ¦_m) β the power flowing through a system per unit of its mass, measured in erg sβ»ΒΉ gβ»ΒΉ. Chaisson proposed FERD as a universal complexity metric: systems higher on the ladder process energy more intensively per unit mass, and the trend across cosmic evolution is toward higher FERD. The ladder spans from galaxies (~0.5 erg/s/g) through stars, biospheres, animals, brains, and modern computers (~10βΈβ10βΉ erg/s/g).
The interactive component computes where a black hole ergosphere falls on this ladder. The formula used is FERD_erg = Ξ΅ cβ΅ / (2GM), derived from the Blandford-Znajek power formula (P_BZ β Ξ΅ αΉ cΒ²) combined with the mass residence time in the ergosphere (t_res β 2GM/cΒ³). Crucially, the accretion rate αΉ cancels: FERD depends only on BH mass and BZ efficiency. Less massive black holes have higher FERD per unit ergospheric mass.
For a Kerr black hole with mass M and BZ efficiency Ξ΅: the ergosphere radius at the equator is r_erg = 2GM/cΒ² (independent of spin). The BZ power scales as P_BZ β Ξ΅ Γ αΉ Γ cΒ². The characteristic mass in the ergosphere at any instant scales as M_erg β αΉ Γ (r_erg/c) = αΉ Γ 2GM/cΒ³. Therefore FERD = P_BZ/M_erg = Ξ΅ cΒ² / (2GM/cΒ³) = Ξ΅ cβ΅ / (2GM). The BZ efficiency Ξ΅ ranges from ~0.05 (low spin) to ~0.42 (maximal spin, Kerr limit).
The Chaisson FERD values for galaxies through computers are π¬ established physics β well-cited observational and engineering values. The IMBH ergosphere calculation uses the BZ formula, which is β theoretically well-grounded but approximate (it assumes the split-monopole field geometry). The interpretation of the ergosphere as a compute substrate is β¦ engineering fiction β speculative but grounded in the established physics of the BZ mechanism.
John Smart's Transcension Hypothesis proposes that advanced civilisations compress toward STEM-dense environments rather than expanding outward. The FERD ladder provides the quantitative motivation: the ergosphere of even a relatively modest IMBH processes energy at a rate per unit mass that exceeds current human technology by ~11β15 orders of magnitude. The Evo Devo Universe framework (Smart & Vidal 2009) interprets this as the next "rung" of cosmic developmental complexity after technological civilisation.
v1.0 β 2026-06-02 Β· Tool content may be revised as scientific knowledge evolves.