OCS / Tools / Accretion → Engineering-Ready Spin
The MTH engineering chain: given OC's IMBH current accretion state, how long until it reaches an engineering-viable spin? Then: what BZ power becomes available, and where would you park a computation substrate?
OC's IMBH is currently in a quiescent/sub-Eddington accretion state with no detected radio or X-ray counterpart. The Bondi–Hoyle rate from the ambient stellar winds and ISM in OC's core sets the mass inflow. Only a fraction F_Bondi actually reaches the horizon.
Prograde disc accretion spins up the IMBH toward the Thorne limit (a★ = 0.998). The spin-up mass fraction is ΔM/M = 1 − √(r_ISCO(a★)/6). At the current quiescent accretion rate, this takes an astronomically long time without engineering assistance.
At the target spin, the BZ mechanism extracts rotational energy electromagnetically. Power scales steeply: P_BZ ∝ B² M² a². The horizon magnetic field is constrained from below by the current accretion rate.
With engineering-viable spin achieved, a computation substrate orbiting the IMBH at the ISCO (or slightly outside) experiences gravitational time dilation — more subjective computation time per external year. The ISCO radius and time-dilation factor are fixed by the target spin.
The time dilation factor γ at r_ISCO means that for every year experienced locally by a near-ISCO substrate, γ years pass at infinity. This is the core MTH efficiency argument: the same computation resources deliver γ× more subjective experience per external year compared to a distant substrate.
At a★ = 0.998 (Thorne limit), r_ISCO ≈ 1.24 r_g and γ ≈ 4.5. At a★ = 0.9, r_ISCO ≈ 2.32 r_g and γ ≈ 1.8.
Computing…