OCS / Tools / OC Survivability Budget

1Orbital Clock → 2Mass Loss Rate → 3Feeding the Engine → 4Engineering Window → ✓Summary
Four-stage workflow · cluster orbit → tidal stripping → IMBH feeding → BZ engineering window

OC Survivability Budget

Four-stage cascade: cluster orbit → tidal stripping → IMBH feeding rate → BZ power budget over OC's remaining lifetime. How many billion years does the civilisation have?

🔬 Established dynamics (stages 1–3) ✦ MTH application (stage 4)
Refs: Baumgardt & Hilker 2018 · Vasiliev & Baumgardt 2021 · King 1962 · Thorne 1974 · No backend · State in URL hash · v1.0 · 2026-06-02
01
OC's Galactic Orbit
Orbital Clock
Set orbital period and pericentre distance to count future passages
▶

Omega Centauri orbits the Milky Way on a retrograde, mildly eccentric orbit with a period of ~300 Myr. Each pericentre passage strips mass from the cluster. Gaia DR3 proper motions (Vasiliev & Baumgardt 2021) constrain the current pericentre distance to ~1.2 kpc.

Inputs
300 Myr
1.2 kpc
Stage 1 outputs
Pericentre passages in 10 Gyr—
Future passages (over the next 12.1 Gyr, OC's current age used as a projection horizon, not a remaining lifetime)—
Current pericentre—kpc
Orbital period—Myr
→Passes to Stage 2: N_future = — pericentre passages · T_orb = — Myr
02
Tidal Stripping · King 1962
Mass Loss Rate
Set stripping fraction and cluster mass to compute dissolution time
▶

At each pericentre, the Milky Way's tidal field strips the outermost stars. The fractional mass loss scales with (r_peri/r_tidal)³ where r_tidal ~ 100 pc is OC's current tidal radius. Baumgardt & Hilker (2018) place the current cluster mass at ~3.5–4.5 × 10⁶ M☉.

Inputs (N_future from Stage 1)
N_future from Stage 1—
3.0 %
4.00 × 10⁶ M☉
Stage 2 outputs
Mass remaining after N_future passages—M☉
Fraction remaining—
Half-mass time T_{1/2}—Gyr
Dissolution time (10% threshold) T_diss—Gyr
Verdict—
→Passes to Stage 3: M_remaining = — M☉ · T_diss = — Gyr · f_strip = —%
03
Accretion from Stellar Population
Feeding the Engine
Set accretion rate and IMBH mass to project final spin-up mass
▶

As the cluster loses mass, the tidal capture rate (proportional to stellar density squared × cluster mass) decreases. The IMBH grows until the cluster runs out of stars. Total mass accreted by dissolution determines whether spin-up to a★ = 0.95 is achievable before the fuel runs out.

Inputs (M_remaining, T_diss, f_strip, T_orb from prior stages)
M_remaining / T_diss from Stage 2—
10⁻³ M☉/yr
8,200 M☉
Stage 3 outputs
Total mass accreted ΔM_accreted—M☉
Final IMBH mass M_f—M☉
Spin-up mass needed (to a★=0.95)—M☉
Spin-up verdict—
→Passes to Stage 4: M_f = — M☉ · ΔM = — M☉ · T_diss = — Gyr
04
MTH Timeline · Blandford-Znajek 1977
The Engineering Window
Set field and spin to compute BZ power budget over the cluster's remaining life
▶

How much BZ energy is available over the cluster's remaining engineerable lifetime? The power increases as spin-up proceeds, then decreases as the cluster loses fuel. This stage assumes spin-up is completed and computes an upper-bound on total extractable energy over T_diss years at the final spin. BZ power scales steeply: P ∝ B² M² a²(1+√(1−a²))².

Inputs (M_f, T_diss from prior stages)
M_f / T_diss from Stages 2–3—
10⁶ T
a★ = 0.950
Stage 4 outputs
BZ power at final spin P_BZ_final—W
Kardashev scale K—
vs. solar luminosity—
Total energy budget E_total (upper bound)—J
E_total vs. Sun × Gyr—
Horizon radius r₊—km
✓ OC Survivability Budget — Full Summary
T_orb
—
Myr
r_peri
—
kpc
T_diss
—
Gyr
M_f (IMBH)
—
M☉
P_BZ_final
—
watts
Kardashev K
—
scale
E_total
—
joules (upper bound)
Spin-up verdict
—
vs. dissolution

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