The Macro Transcension Hypothesis: Spinning Black Holes in Dense Stellar Clusters as Thermodynamic Attractors for Advanced Civilizations, with Omega Centauri as an Observational Test Bed

1. Introduction

The Fermi paradox, in its modern form (Hart 1975; Tipler 1980; Webb 2015; Ćirković 2018; Forgan 2019), rests on an expansionist premise: that at least some technological civilizations should grow outward across interstellar distances, and that such growth, sustained for even a small fraction of galactic history, would be conspicuous. The premise is quantitatively robust. Self-reproducing probe architectures permit galaxy-scale colonization in 10⁶–10⁸ years (Tipler 1980; Freitas & Gilbreath 1982), intergalactic expansion is energetically cheap for a mature civilization (Armstrong & Sandberg 2013), and surveys for the waste heat of large-scale energy harvesting have returned null results across ~10⁵ galaxies (Wright et al. 2014; Griffith et al. 2015). The observed silence therefore demands either that technological life is extremely rare, that it reliably destroys itself, or that the expansionist premise is wrong.

A minority tradition in the literature attacks the premise itself. Smart (2012) proposed the transcension hypothesis: that the developmental trajectory of intelligence points not outward but inward, toward ever denser, faster, and more efficient configurations of matter and energy ("STEM compression" of space, time, energy, and matter) terminating, in Smart's telling, at black-hole-scale densities and an effective exit from the observable universe. Sandberg, Armstrong & Ćirković (2016) proposed the aestivation hypothesis: that civilizations which value computation should defer it to the far future, when the cosmic microwave background (CMB) has cooled and each erased bit costs less free energy, and should therefore be dormant now. Both proposals share a key insight, that the thermodynamics of computation is the correct lens through which to predict the behaviour of mature intelligence, and both have been criticized on physical grounds. Smart's mechanism for leaving the universe is not specified in testable form, and the aestivation argument was shown by Bennett, Hanson & Riedel (2019) to rest on a thermodynamic error: free energy not harvested now is largely lost, not banked, so a computation-maximizing civilization should collect resources now even if it spends them later.

This paper develops a third member of that family, which we call the Macro Transcension Hypothesis (MTH). Its core claim is that the inward trajectory identified by Smart has a concrete, macroscopic, observationally accessible destination in ordinary astrophysics: rapidly spinning massive black holes embedded in dense, dynamically old stellar systems. No new physics, no exit from the universe, and no multi-gigayear dormancy are required. The advantages that drive the migration (accretion power at up to ~60 times the mass-energy efficiency of fusion, an event horizon serving as an entropy sink of unlimited capacity, information storage at the Bekenstein–Hawking density, and gravitational time dilation as a controllable computational resource) are all available in the present epoch, and all follow from textbook general relativity and black-hole thermodynamics (Misner, Thorne & Wheeler 1973; Bardeen, Press & Teukolsky 1972; Bekenstein 1973, 1974). The hypothesis predicts that the most advanced civilizations remain present but electromagnetically invisible, because maximum computational efficiency, viewed from outside, looks like silence.

The MTH would remain idle philosophy if it did not select targets. The selection criteria, a massive black hole of modest depth (intermediate, not supermassive), a dense retinue of low-mass stars as fuel, dynamical age sufficient for any migrating civilization to have arrived and matured, and a quiescent electromagnetic environment, converge on a short list of Galactic systems, at the top of which sits Omega Centauri (ω Cen, NGC 5139): the Milky Way's most massive globular cluster, widely interpreted as the stripped nucleus of an accreted dwarf galaxy (Hilker & Richtler 2000; Bekki & Tsujimoto 2019; Ibata et al. 2019), host to ~10⁷ stars of mean age 12.08 ± 0.01 Gyr (Clontz et al. 2024), and (since the detection of seven fast-moving stars within its central 3 arcsec) host to the strongest current candidate for an intermediate-mass black hole (IMBH) in the Galaxy (Häberle et al. 2024a). That candidate is simultaneously the subject of a sharp observational controversy: combined stellar-kinematic and millisecond-pulsar-timing analysis places a 3σ upper limit of ~6,000 M_☉ on any central point mass (Bañares-Hernández et al. 2025), formally inconsistent with the kinematic lower bound. And it is electromagnetically dark to remarkable depth: neither ~170 hours of ATCA radio integration (Mahida et al. 2026), nor JWST infrared photometry (Chen et al. 2025), nor a ~290 ks Chandra exposure (Haggard et al. 2013) detects any accretion signature. Every element of this situation (a contested central mass, perfect electromagnetic silence, an imminent decisive instrument in LISA) makes ω Cen a natural laboratory for testing inward-migration hypotheses, entirely independent of whether the MTH is true.

1.1 Claims and non-claims

Because the argument mixes established physics with speculative inference, we state the epistemic register of each claim explicitly. The paper makes three claims of different strength:

1. (Established physics plus a comparative synthesis.) Spinning black holes in dense old clusters are, by a wide quantitative margin, the most thermodynamically favourable environments in the present-day universe for long-term, large-scale computation. The ingredient results are established physics; the optimality claim is a synthesis over a stated comparison set (fusion, Dyson-type stellar harvesting, and cold-space computing), defended quantitatively in Section 4 using standard results, and is independent of any claim about extraterrestrial intelligence. The ranking of cluster IMBHs above supermassive holes rests partly on strategic rather than thermodynamic criteria (hazard exposure, contested resources), which we treat separately in Section 5.4.
2. (Speculative hypothesis.) If long-lived technological civilizations exist and even a subset optimizes for computational capacity, the environments of claim 1 act as attractors, and the resulting migration resolves the Fermi paradox without rare-Earth or doomsday assumptions. This is the MTH proper, stated formally in Section 3. We regard it as less parsimonious than the null hypothesis (technological life is rare or absent) and say so.
3. (Observational program.) Whether or not claim 2 is true, it generates instrument-matched, time-bounded, falsifiable predictions at ω Cen, several of which will be adjudicated by existing or funded instruments within ~15 years. This program is presented in Section 7.

We do not claim that ω Cen hosts a civilization; we do not claim the IMBH is confirmed (it is not); and we do not claim the observed electromagnetic silence is evidence for the MTH, since it is equally consistent with the simpler gas-starvation explanation that we adopt as the null hypothesis throughout.

2. Relation to prior work

2.1 The expansionist mainstream

The canonical statements of the Fermi paradox (Hart 1975; Tipler 1980) treat interstellar expansion as the default behaviour of technological life, an assumption sharpened by Armstrong & Sandberg (2013), who showed that a single mature civilization could seed every galaxy within several billion light-years using a fraction of one star's output. The "grabby aliens" model of Hanson et al. (2021) quantifies the selection effect: if loud (expanding) civilizations exist at any appreciable rate, they dominate the future light cone, and our own early arrival is informative about their density. Observational programs built on the expansionist premise, radio and optical SETI (Tarter 2001), waste-heat surveys (Dyson 1960; Wright et al. 2014; Griffith et al. 2015), and the broader technosignature framework (Wright et al. 2022; Socas-Navarro et al. 2021; Lingam & Loeb 2021), have produced consistent null results. Within the expansionist frame, these nulls force the unattractive trilemma of rarity, doom, or concealment.

2.2 The inward-migration family

The MTH belongs to a smaller family of proposals holding that mature intelligence migrates down thermodynamic gradients rather than out across space.

Transcension. Smart (2012) argued that the developmental history of complexity on Earth exhibits sustained compression in space, time, energy, and matter ("STEM compression"), and extrapolated to a future in which civilizations engineer environments of black-hole density and disappear from the observable universe. The MTH adopts the compression premise but rejects the terminal step: nothing in known physics permits or requires an exit from the universe, and a hypothesis terminating in unobservable territory cannot be tested. The MTH instead halts the inward trajectory at a macroscopic astrophysical object (an existing massive black hole) where every claimed advantage is calculable and several are observable. Hence macro transcension.

Aestivation. Sandberg, Armstrong & Ćirković (2016) proposed that civilizations defer computation until the CMB cools, gaining a factor of up to ~10³⁰ in computations per joule, and so should currently be dormant. Bennett, Hanson & Riedel (2019) showed the argument neglects the irreversible loss of free-energy resources not collected promptly: stars burn whether or not anyone harvests them, so maximizers should be active now. The MTH avoids this objection by construction: instead of waiting for a colder universe, it imports a colder-than-CMB entropy sink into the present: waste entropy crossing an event horizon increases horizon area in accordance with the generalized second law (Bekenstein 1974), at an effective marginal temperature far below the CMB's 2.7 K (Section 4.2). An MTH civilization harvests aggressively in the present epoch (consistent with the Bennett–Hanson–Riedel optimality argument) while enjoying much of the efficiency gain that motivated aestivation.

Black holes as civilization infrastructure. The conceit is older than SETI's engagement with it. Penrose (1969) introduced rotational-energy extraction with an advanced-civilization framing, and Misner, Thorne & Wheeler (1973, §33.7) formalized it as the garbage-dump thought experiment: a civilization lowers its waste to just outside the horizon, releases it, and recovers up to 29 per cent of the rest mass as work. Thorne (1994) staged the same power station for a popular audience, and Frolov & Novikov (1998, §12) give the textbook treatment of black holes as energy sources for civilizations. The present series is a completion of that thread. Within SETI proper, several authors have treated black holes as energy sources or computational substrates for advanced intelligence: Inoue & Yokoo (2011) proposed Dyson-type collectors around an accreting supermassive black hole; Hsiao et al. (2021) computed the detectability of a "Dyson sphere around a black hole" harvesting disk luminosity; Opatrný, Richterek & Bakala (2017) analysed the inverted configuration in which a black hole serves as the cold reservoir of a heat engine run against the warmer sky; Vidal (2011, 2014) argued that black-hole-coupled ("stellivore") systems are the natural attractor for cosmic intelligence; and Dvali & Osmanov (2023) analysed black holes as quantum information processors for extraterrestrial civilizations, predicting characteristic high-energy neutrino emission from artificial micro-black-hole computers. Lacki & DiKerby (2025) survey the corresponding high-energy SETI opportunity, and the Dyson Minds workshop (Curtis et al. 2026) has since brought this thread into mainstream observational planning, recommending anomaly-detection searches of archival WISE, JWST, and EHT data for black-hole-hosted intelligence, with a focus on supermassive hosts. The MTH synthesizes this thread and adds the two elements it has lacked: a selection theory specifying which black holes are preferred and why (intermediate-mass, high-spin, cluster-embedded; Section 3.1), and a named, ranked observational target with a costed test program.

Kardashev and his inversion. The Kardashev scale (Kardashev 1964) ranks civilizations by total energy throughput, implicitly rewarding outward expansion. Barrow (1998) proposed the complementary inward scale: mastery over ever-smaller scales of structure. The MTH is the astrophysical completion of Barrow's inversion — the observation that the universe already provides, free of charge, the densest stable structures that inward mastery could aim at, and that the rational endpoint of a Barrow-type trajectory is therefore relocation rather than fabrication. Bradbury (1999) reached a related conclusion from the engineering side: his Matrioshka-brain analysis shows stellar-powered computation is ultimately limited by radiator area and sink temperature, the constraints an event horizon eliminates.

2.3 What is new here

To our knowledge this paper is the first to (i) state the inward-migration resolution of the Fermi paradox as a falsifiable selection theory over real astrophysical objects; (ii) integrate the generalized second law, the Landauer bound, Kerr accretion efficiency, Blandford–Znajek extraction, and Bekenstein–Hawking storage into a single quantitative budget for a civilization-scale computer hosted by an existing black hole; and (iii) attach the resulting predictions to a specific system (ω Cen) with instrument-matched falsification thresholds and timelines. Each ingredient exists in the literature; the synthesis, the selection criteria, and the test program are new.

3. The hypothesis

We state the MTH as four postulates.

The hypothesis (MTH). If P1–P3 hold, then the oldest computation-maximizing civilizations in the Galaxy have already relocated to environments of the P2 class; their absence from planetary systems, the radio spectrum, and waste-heat surveys is a selection effect of the thermodynamic gradient; and the appropriate search strategy is targeted scrutiny of the small set of P2-optimal Galactic systems for the P4 residues.

Three corollaries sharpen the contrast with neighbouring hypotheses. First, against aestivation: the MTH predicts present activity in P2 environments, not dormancy, so it is not vulnerable to the Bennett–Hanson–Riedel objection. Second, against the dark-forest family of concealment hypotheses: silence here is a by-product of efficiency, not a strategic choice, so the MTH requires no game-theoretic coordination among civilizations. Third, against Smart's original transcension: every MTH process occurs in ordinary spacetime around an ordinary Kerr black hole, so the hypothesis remains permanently coupled to observation.

3.1 Selection criteria over host systems

P2 implies a ranking of real systems. The optimum is set by competing requirements:

1. Black-hole mass in the intermediate range (10³–10⁵ M_☉). Energy extraction scales with available fuel and with Eddington-limited throughput (∝ M), favouring larger M; but tidal disruption of solid infrastructure at the innermost stable circular orbit (ISCO) becomes less constraining at larger M, while two costs grow with M: the Bekenstein–Hawking storage already saturates any plausible need at 10⁴ M_☉, and supermassive holes sit in deep galactic-centre potentials crowded with disruptive astrophysics (Section 5.4). The intermediate range secures every advantage at minimal exposure.
2. High spin, or spin-up feasibility. The Blandford–Znajek channel and the deep-ISCO efficiencies require a_★ ≳ 0.9; a hole of modest spin can be spun up by prograde disk accretion at a calculable mass cost (Thorne 1974), provided fuel exists (criterion 3).
3. A dense, old, low-mass stellar reservoir. Sustained Eddington-limited feeding of a ~2×10⁴ M_☉ hole consumes of order one solar mass per two millennia (Section 4.1); at ω Cen's central density the inner parsec supplies ~3×10⁴ stars and the central ~10 pc of order 10⁶, at relative velocities of tens of km s⁻¹. The contested status of this fuel is era-relative: it is uncontested by fusion-era economics, but under star lifting the same M dwarfs are prize fuel (fully convective, hence hydrogen-complete, with ~10¹²-yr lifetimes; Scoggins & Kipping 2023), so among computation-maximizing lineages the reservoir is maximally contested, an early-arrival premium developed in the companion economics paper.
4. Dynamical age and quiescence. A system ≳10 Gyr old has been reachable by any Galactic civilization arising in the first stellar generations; a relaxed, gas-poor environment minimizes both natural accretion noise and hazards to infrastructure.

Milky Way globular clusters with massive-IMBH candidates satisfy all four criteria simultaneously; ω Cen satisfies them maximally (Section 5). The Galactic Centre fails criteria 1 and 4; isolated stellar-mass black holes fail criterion 3; young massive clusters fail criterion 4. Retention is not the bottleneck: survival analyses of IMBHs in dense clusters find that holes above ~10³ M_☉ are generally retained against dynamical ejection over a Hubble time (Martinez et al. 2026), so if formation occurs at all, the P2 class is populated today.

Because a selection theory that never exhibits its selection invites the charge of unfalsifiability by retreat, Table A scores the leading Galactic candidates against the four criteria. The ranking is coarse (the IMBH-evidence column in particular is contested for every entry), but it is the operational content of P2: the class-level kill statement of Section 8 quantifies over exactly these systems.

4. The thermodynamic and computational case

This section defends postulate P2 quantitatively. Throughout, M is the black-hole mass, a_★ ≡ Jc/GM² ∈ [0,1) the dimensionless spin, r_g ≡ GM/c² the gravitational radius, and we evaluate fiducial numbers at M = 2×10⁴ M_☉, the geometric midpoint of the contested ω Cen range (Section 5). All results in this section are standard physics; no claim about extraterrestrial intelligence is made until Section 6.

4.1 Energy: accretion and spin extraction versus fusion

Thin-disk efficiency. Matter spiralling through a geometrically thin, radiatively efficient disk is released at the ISCO binding energy. For a circular equatorial orbit around a Kerr hole, the specific energy at the ISCO gives a radiative efficiency (Bardeen, Press & Teukolsky 1972; Novikov & Thorne 1973)

which rises from η = 1 − √(8/9) ≈ 0.057 at a_★ = 0 (r_ISCO = 6 r_g) to 0.321 (pure geodesic value; the photon-capture-corrected equilibrium efficiency is ≈0.30) at the Thorne (1974) radiative spin-equilibrium limit a_★ = 0.998, and formally to 1 − 1/√3 ≈ 0.423 as a_★ → 1 (Fig. 1). Hydrogen fusion releases 0.71 per cent of the rest mass burned, but a real star offers only its hydrogen fraction X_H ≈ 0.7 to that channel, so complete fusion of a star yields ≈5×10⁻³ of stellar mass; an unassisted main-sequence star burns roughly a tenth of its mass over its lifetime, so a Dyson-type collector (Dyson 1960) captures a lifetime yield of order 7×10⁻⁴. Per unit of fuel mass under the civilization's control, disk accretion onto a high-spin hole thus outperforms complete fusion of the same mass by a factor of ~11 (Schwarzschild) to ~85 (extremal), and outperforms Dyson harvesting without star lifting by a factor of ~80–600. The comparison set matters, because star lifting changes it: a civilization that strips the envelope and feeds the core accesses close to the full hydrogen inventory (Criswell 1985; Matloff 2017; Scoggins & Kipping 2023), raising the yield toward the 5×10⁻³ ceiling and collapsing the Dyson disadvantage to the same ~11–85 as complete fusion. The entropy-sink and storage advantages (Sections 4.2–4.3) are independent of which factor applies.

Power throughput. The sustainable luminosity is bounded by the Eddington limit,

giving 1.0×10³⁵, 2.5×10³⁵, and 6.3×10³⁵ W at M = 8.2×10³, 2×10⁴, and 5×10⁴ M_☉ respectively (Frank, King & Raine 2002; Shapiro & Teukolsky 1983) — some 3×10⁸–2×10⁹ times the bolometric output of the Sun across that mass range (6.6×10⁸ at 2×10⁴ M_☉), and hence of any solar Dyson swarm (Fig. 2). The corresponding Eddington accretion rate, Ṁ_Edd = L_Edd/ηc², is remarkably modest: at η = 0.1 and M = 2×10⁴ M_☉, one solar mass sustains the limit for ~2,300 years. At ω Cen's adopted central density (~3×10³ M_☉ pc⁻³; Table 1) the central parsec holds ~1.3×10⁴ M_☉, roughly 3×10⁴ stars, or ~7×10⁷ yr of Eddington fuel on its own; the working reservoir is the central ~10 pc, whose ~10⁶ stars fuel Eddington-limited operation for 10^8–9 years using bodies (brown dwarfs, low-mass M dwarfs, white dwarfs) that no fusion-based economy values, at the delivery cost priced in Section 6.

Spin energy and the Blandford–Znajek channel. A Kerr hole stores extractable rotational energy

reaching 0.29 Mc² ≈ 1.0×10⁵¹ J for M = 2×10⁴ M_☉ as a_★ → 1: a reservoir equal to the entire lifetime fusion output of ~10⁷ Suns, storable indefinitely and tappable on demand. The bracketed quantity is the Christodoulou–Ruffini reducible energy, the difference between M and the irreducible mass M_irr (Christodoulou 1970; Christodoulou & Ruffini 1971); extraction is reversible only in the limit of vanishing horizon-area increase, and inefficient extraction raises M_irr permanently, destroying future capacity, a distinction that matters for the spin-fossil reasoning of Section 7. That this energy is extractable in principle was shown by the ergosphere mechanism of Penrose (1969) and Penrose & Floyd (1971); the astrophysically efficient extraction mechanism is electromagnetic: a horizon threaded by poloidal magnetic flux Φ supplied by an accretion disk acts as a unipolar inductor, driving Poynting-flux jets with power P_BZ ∝ Φ²Ω_H², where Ω_H is the horizon angular frequency (Blandford & Znajek 1977). In the membrane paradigm of Thorne, Price & Macdonald (1986) the horizon carries a surface resistivity of 377 Ω and the whole configuration reads as a battery with internal resistance, the engineering-facing form of the mechanism and the one relevant to Section 6's power-station framing. In the magnetically arrested disk (MAD) regime, general-relativistic magnetohydrodynamic simulations find jet efficiencies η_jet ≡ P_jet/Ṁc² ≈ 1.4 at a_★ ≈ 0.99 (Tchekhovskoy, Narayan & McKinney 2011; Tchekhovskoy 2015): the jet carries more energy than the accreted rest mass, the excess drawn from spin. The BZ scaling has recently been confirmed from first principles by ab-initio particle-in-cell simulations of Kerr magnetospheres (Meringolo, Camilloni & Rezzolla 2025), which additionally identify equatorial magnetic reconnection as a supplementary extraction channel (Comisso & Asenjo 2021; Camilloni & Rezzolla 2025); one 2026 preprint reports transient MAD states with jet power exceeding accretion power by over two orders of magnitude (Nathanail 2026, not yet peer-reviewed). For the MTH it suffices that η_jet ≳ 1 is robust across methods: an engineered MAD configuration around a spun-up IMBH is, per unit fuel, the most efficient large-scale power plant permitted by demonstrated physics.

Spin-up economics. A hole of low natal spin is itself improvable. Prograde thin-disk accretion drives a_★ → 0.998 after the hole grows by a factor ≈2.4 (Thorne 1974); for an initial 2×10⁴ M_☉ hole this costs ~3×10⁴ M_☉ of accreted matter (of order 10^4–5 cluster stars) and, at Eddington throughput, ~10⁸ years. The investment multiplies all subsequent per-unit-fuel returns by up to ~6 (Fig. 1) and unlocks the BZ reservoir. The corollary for observers: spin is a key parameter of the system's history (Section 7), since the MTH requires engineered systems to approach near-extremal spin; the converse inference is weaker, because some natural formation channels, in particular coherent disk growth in a gas-rich nucleus, also reach high spin (Reynolds 2021; Section 7).

4.2 Entropy disposal: the horizon as the ultimate cold reservoir

Landauer's principle sets the minimum thermodynamic cost of irreversible computation: erasing one bit dissipates at least k_BT ln 2 into a reservoir at temperature T (Landauer 1961; Bennett 1982; Parrondo, Horowitz & Sagawa 2015), a bound verified experimentally (Bérut et al. 2012). Reversible logic evades the bound for intermediate steps (Bennett 1973; Toffoli 1980; Fredkin & Toffoli 1982; Athas et al. 1994; Frank 2002), but error correction, measurement, and memory reuse impose a residual erasure budget on any real computer (Wolpert 2019). For a conventional deep-space computer the reservoir floor is the CMB at T_γ = 2.7 K, so the marginal cost is k_BT_γ ln 2 = 2.6×10⁻²³ J per bit. This is the floor that aestivation proposes to lower by waiting ~10¹² years (Sandberg et al. 2016).

An event horizon lowers it in the present epoch. By the generalized second law (GSL), the sum of black-hole entropy S_BH = k_Bc³A/4Għ and exterior entropy is non-decreasing, and entropy carried across the horizon is accounted by the area increase (Bekenstein 1973, 1974; Bousso 2002). A computation platform orbiting the hole may therefore dump its waste entropy into the horizon rather than radiating it to the sky. The marginal energy cost of horizon disposal is set by the horizon temperature

(Hawking 1974, 1975): T_H ≈ 3×10⁻¹² K at 2×10⁴ M_☉, twelve orders of magnitude below the CMB. A bit dumped at the horizon costs k_BT_H ln 2 ~ 3×10⁻³⁵ J against 2.6×10⁻²³ J for CMB radiation (Fig. 3). In practical terms the erasure cost ceases to be the binding constraint on computation; the budget shifts to transport of waste heat to the horizon (radiative or conductive tethering from the ISCO swarm inward), an engineering loss rather than a thermodynamic floor. The quantified gain from this substitution is the ~10¹² temperature ratio between the CMB and the horizon; the larger ~10³⁰ factor cited by Sandberg et al. (2016) assumes cooling to temperatures far below the horizon temperature used here and is not directly comparable. The substitution's decisive property is that it operates without waiting, and therefore without forfeiting the free energy that Bennett, Hanson & Riedel (2019) showed dormant civilizations irretrievably lose. The related configuration of Opatrný, Richterek & Bakala (2017), a shell absorbing CMB radiation as its hot reservoir and rejecting entropy to a central black hole, demonstrates the same thermodynamic asymmetry in a fully worked classical setting.

The claim should also be stated in its energy-conservation form, because that is where the mainstream objection lands. Curtis et al. (2026) state the standard position: Dyson-scale computation must reradiate nearly all of the energy it absorbs, so mid-infrared thermal emission is the robust technosignature of black-hole-hosted intelligence. For a horizon-sink architecture the premise fails, and it fails on energy grounds rather than entropy grounds: the waste carriers themselves cross the horizon, and their energy goes with the entropy. Writing f_sink for the fraction of waste energy delivered into the capture cone (a vocabulary adopted throughout this series), only the missed fraction (1 − f_sink) must be reradiated, at swarm temperature; the absorbed remainder raises M and thereby lowers T_H further, so the channel is weakly self-improving. The disagreement with Curtis et al. (2026) is thus quantitative and falsifiable: the predicted mid-infrared residue scales with (1 − f_sink) rather than with the full computational throughput.

The k_BT_H ln 2 figure is the marginal cost of disposal at the horizon; it is not the delivered cost from an orbiting platform, and the gap between the two can be estimated rather than merely flagged. Consider radiative delivery, the least demanding channel. Efficient absorption requires a carrier wavelength λ ≲ r_g, the geometric-optics condition for capture rather than diffraction around the hole (aiming is a separate and easier requirement, treated below). At M = 2×10⁴ M_☉, r_g ≈ 3×10⁷ m, so the vacuum-gravitational floor on the carrier energy is E_γ ≳ hc/r_g ≈ 7×10⁻³³ J, corresponding to a frequency of ~10 Hz. That floor is unreachable through plasma: propagation requires ν > ν_p = 8.98 kHz √(n_e/cm⁻³), and even the cluster's ambient n_e = 0.23 cm⁻³ gives ν_p ≈ 4.3 kHz, while any fed inner-flow environment (n_e ~ 10⁴–10⁸ cm⁻³ inside ~10² r_g) gives ν_p ≈ 1–90 MHz. The minimum propagating carrier energy is therefore set by the plasma cutoff, at ~10⁻²⁷–10⁻²⁶ J, three to six decades above hc/r_g. Two consequences follow. First, single-bit-per-photon delivery no longer suffices: at the plasma-cutoff carrier energy the advantage over the CMB would erode toward 10⁴–10⁷. What preserves the realized range is dense coding: a carrier may bear many bits, up to the Bekenstein channel capacity (Bekenstein 1981; Bousso 2002), and coding at a modest fraction of capacity restores the delivered cost per bit to a factor of 10⁶–10⁹ below the CMB figure of 2.6×10⁻²³ J. Second, matter carriers evade the cutoff entirely: cold mass dropped down the capture cone crosses the horizon with its entropy and energy aboard and no dispersion relation to satisfy, and serves as the fallback channel wherever the local plasma forbids cheap photons. Charging realistic engineering losses against these channels (pointing and capture inefficiency, error-correction overhead, the fraction of carriers scattered rather than absorbed) leaves a defensible realized gain of ~10⁶–10⁹ over the 2.7 K sky. Gravitational bookkeeping does not change this range: energy accounted at a platform of radius r ≳ 10² r_g is redshifted at infinity by the platform's lapse factor, a ≈1 per cent correction at these radii. The realized economy therefore sits well above the k_BT_H ln 2 floor and well below the CMB figure, and we quote 10⁶–10⁹ rather than the floor-to-floor ratio of ~10¹² wherever the realized gain is meant. An improvement of six orders of magnitude over the 2.7 K sky already dominates the aestivation trade.

Delivery geometry can be derived rather than assumed. The photon-capture cross-section of a Schwarzschild hole is σ = πb_crit² = 27πr_g², with critical impact parameter b_crit = 3√3 r_g; from a platform at r = 10² r_g the capture target subtends a solid-angle fraction Ω_c/4π = 6.75×10⁻⁴, so isotropic emission delivers less than a thousandth of its power to the horizon. Reaching f_sink → 1 therefore requires a beaming gain ≳1.5×10³, which is optically trivial: the capture cone has half-angle θ_c ≈ 0.052 rad, so diffraction demands only an aperture D ≳ 23λ, and the étendue (concentration) limit 1/sin²θ_c ≈ 3.7×10² puts the optic area at a few hundred times the radiator area. (The 27πr_g² figure is the Schwarzschild value; the near-extremal prograde equatorial cross-section is somewhat smaller and anisotropic, an O(1) correction.) The binding term in the delivery budget is re-interception within the swarm rather than aiming or aperture: beamed flux must traverse the swarm itself, and the intercepted fraction scales with the swarm covering fraction (Paper E).

4.3 Information storage: the Bekenstein–Hawking archive

The Bekenstein bound limits the information content of any bounded system (Bekenstein 1981; Casini 2008); black holes saturate it, with

i.e. ~6×10⁸⁵ bits at 2×10⁴ M_☉ (Bekenstein 1973; Hawking 1975; Lloyd 2000). That coefficient is the Schwarzschild value; since the architecture ends near-extremal, we quote one self-consistent pair: at a_★ = 0.998 the Kerr horizon area per unit M² is 0.53× Schwarzschild, so a 2×10⁴ M_☉ hole at that spin stores ≈3×10⁸⁵ bits, and the factor-2.4 mass growth of the spin-up path (Section 4.1) more than recovers the difference through the M² scaling. Information crossing the horizon is scrambled but, by unitarity, not destroyed; retrieval timescales via Hawking radiation are, however, of order the evaporation time, ~10⁶⁷(M/M_☉)³ yr (Page 1976) — the archive is functionally write-only. Black holes likewise saturate the Margolus–Levitin bound on processing rate, 2E/πħ operations per second (Margolus & Levitin 1998; Lloyd 2000). We treat these saturation properties not as a usable disk drive but as the formal statement that no material technology can out-store or out-compute the object the civilization is already orbiting.

4.4 Time dilation as an engineering parameter

A platform on a circular equatorial geodesic at radius r around a Kerr hole runs slow relative to infinity by

(Bardeen, Press & Teukolsky 1972): dτ/dt = √½ ≈ 0.707 at the Schwarzschild ISCO, falling to ≈0.093 (a factor ~11) at the prograde ISCO for a_★ = 0.998 (Fig. 4). Larger factors require powered non-geodesic hovering at diverging thrust cost and are not usable by stable platforms. The ~11:1 ceiling is set by the Thorne (1974) spin-equilibrium limit a_★ = 0.998 rather than by orbital stability: the ISCO proper-time ratio falls toward zero as a_★ → 1, and it is the accretion physics capping the spin that caps the dilation. A tiered swarm can therefore place archival and slow-integration processes deep (subjectively skipping across external time) and interactive processes high, with the choice of orbit acting as a clock-rate dial — a resource with no terrestrial analogue, though we note its strategic value (e.g. outwaiting external change) trades directly against responsiveness. The dial is two-way: viewed from outside, a deep tier both runs and receives 11× slower in external time, so deep placement taxes bandwidth to, and coherence with, the shallow tier; and uplink photons arrive blueshifted by the same factor, each depositing ~11× its emitted energy at the deep receiver.

4.5 Why inward beats outward for a computation-maximizer

The expansionist default implicitly maximizes resource acquisition; P1 civilizations maximize computation, and the two diverge. Expansion multiplies harvested mass at most polynomially in time (∝ t³ for spherical growth at fixed speed) while imposing light-lag decoherence on any shared computation: a civilization spread over 10³ light-years cannot function as one computer on subjective timescales shorter than millennia. Concentration, by contrast, multiplies the yield per unit mass by the factors of Section 4.1 (up to ~600 over Dyson harvesting without star lifting), lowers the realized erasure cost by 10⁶–10⁹ (Section 4.2), and keeps the entire system within light-seconds of itself. The undiscounted maximizer is a real exception: expansion's t³ mass growth eventually beats any fixed per-unit-mass advantage, so the inward gradient binds only under at least one of three auxiliary assumptions — temporal discounting, latency-bound unified computation, or bounded planning horizons — which we fold into P1 explicitly. Under any of them, the gradient points inward once beamed-sail transport makes a cluster-hosted IMBH reachable at negligible marginal cost (Lubin 2016; Armstrong & Sandberg 2013). We stress the modesty of the claim actually needed: P1 requires only that some civilizations follow this gradient. Expansionist and stay-at-home civilizations may coexist with migrators; the Fermi-relevant point is that the oldest and most capable optimizers, those whose absence the paradox finds most puzzling (Hanson et al. 2021), are the ones the gradient captures.

4.6 Why one hole rather than many

The comparison set for P2 must include a rival platform that the falsification program itself puts on the table: the dark remnant swarm of hypothesis H₁ (Section 7). Under H₁ the centre of ω Cen contains an extended 2–3×10⁵ M_☉ component of stellar-mass black holes (Bañares-Hernández et al. 2025), twelve times the mass of the fiducial 2×10⁴ M_☉ IMBH. Because L_Edd ∝ M, the swarm's aggregate Eddington power is ~3.2×10³⁶ W against the IMBH's 2.5×10³⁵ W: on raw power the "falsifying" configuration is the better platform by a factor of ~13, and a selection theory that ignored this would be assuming its conclusion. Table B prices the two configurations against the P2 axes.

The IMBH wins decisively on three of the four P2 axes and loses on the fourth. Storage scales as ΣM_i², so fragmenting the central mass into 2.5×10⁴ holes of 10 M_☉ costs a factor of 160 even against the twelvefold mass advantage. Sink depth scales as T_H ∝ M⁻¹, a 2000× edge for the IMBH, and the edge survives the delivery-level accounting of Section 4.2: the realized erasure economy tracks the delivered carrier cost rather than T_H directly, and the vacuum carrier floor hc/r_g is 1.3×10⁻²⁹ J for a 10 M_☉ hole against 6.7×10⁻³³ J for the IMBH, the same ~2×10³ ratio. The ISCO tidal field, ∝ M⁻² at fixed r/r_g, is 4×10⁶ times harsher at 10 M_☉, excluding all but dust-scale hardware from the deep orbits where the dilation and efficiency gains live. And a computation distributed over the swarm pays parsec-scale light lag between nodes, against milliseconds across a single working orbit, failing the latency-bound condition of Section 4.5 by construction. A computation-maximizer offered both configurations takes the single hole, and would pay a large premium to consolidate.

This derivation does real work in the falsification program. T3 (Table 3) treats a LISA-resolved remnant swarm as a decisive falsifier, and this subsection is why: the swarm loses on storage, sink depth, and tides by two to six orders of magnitude, so a maximizer with gigayears of run of the cluster would not have left the central mass in that configuration. T3 is thereby a derived kill switch rather than a stipulated one.

5. Omega Centauri as the optimal observational target

5.1 The cluster

ω Centauri is the most massive Galactic globular cluster (M_cl ≈ 4×10⁶ M_☉, ~10⁷ stars; Baumgardt & Hilker 2018), at a kinematic distance of 5.49 ± 0.06 kpc (Häberle et al. 2025), in ~2σ tension with the Gaia EDR3 parallax (5.24 ± 0.11 kpc; Soltis, Casertano & Riess 2021), whose error budget is dominated by the parallax zero-point systematics discussed by those authors, and consistent with the combined catalogue value (5.43 ± 0.05 kpc; Baumgardt & Vasiliev 2021); nothing in this paper depends on the difference. It is anomalous among globular clusters in nearly every respect that matters here: it hosts multiple stellar populations spanning a broad metallicity range (Johnson & Pilachowski 2010), a mean stellar age of 12.08 ± 0.01 Gyr with an intrinsic spread of 0.75 Gyr (Clontz et al. 2024), significant rotation, and an associated tidal stream (Ibata et al. 2019) — the consensus interpretation being that it is the surviving nucleus of a dwarf galaxy accreted and stripped by the Milky Way (Hilker & Richtler 2000; Bekki & Tsujimoto 2019). Table 1 summarizes the parameters used in this paper.

For the MTH selection criteria of Section 3.1, the stripped-nucleus origin matters twice over. First, nuclear star clusters are the environments most likely to form and retain IMBHs (Greene, Strader & Ho 2020). Second, the age structure implies that any technological lineage arising anywhere in the progenitor dwarf (or in the early Milky Way) has had ≳8 Gyr to locate, reach, and develop the system: at beamed-sail transit speeds of 0.1–0.2 c (Lubin 2016), crossing the Galaxy takes ≲10⁶ years, roughly eight thousand times shorter than the available window.

5.2 The IMBH candidate and the mass tension

Evidence for a central dark mass in ω Cen has accumulated for two decades, from integrated kinematics (Noyola, Gebhardt & Bergmann 2008) through proper-motion modelling that initially yielded only upper limits at the ~10⁴ M_☉ level (van der Marel & Anderson 2010), with stellar-mass black-hole subsystems long advanced as the alternative explanation (Zocchi, Gieles & Hénault-Brunet 2019; Breen & Heggie 2013) and a systematic N-body survey concluding that no Galactic globular cluster, ω Cen included, required an IMBH at all (Baumgardt et al. 2019). The situation changed qualitatively when Häberle et al. (2024a), using a proper-motion catalogue of 1.4 million stars built from over 500 HST epochs (Häberle et al. 2024b), identified seven stars within 3 arcsec of the cluster centre moving faster than the local escape velocity. Their velocities alone require a point mass ≥8,200 M_☉; including acceleration limits on the same stars raises the lower bound to 21,100 M_☉ at 99 per cent confidence (main text of Häberle et al. 2024a). Independent N-body modelling finds that an IMBH grown in situ to ~5×10⁴ M_☉ reproduces the present-day cluster structure and fast-star population (González Prieto, Rodriguez & Cabrera 2025).

Against this stands Bañares-Hernández et al. (2025): a joint analysis of stellar kinematics and timing accelerations of the cluster's millisecond pulsars that places a 3σ upper limit of ~6×10³ M_☉ on any central point mass, favouring instead an extended central dark component of ≈2–3×10⁵ M_☉, naturally interpreted as a centrally concentrated cluster of stellar remnants. The most recent joint MeerKAT–Parkes timing analysis, by contrast, finds its measurements insensitive to an IMBH in the 10³–10⁴ M_☉ range and places a 90 per cent upper limit of <10⁵ M_☉ on the central mass (Colomí i Bernadich et al. 2026), a bound compatible with both camps. The two leading results are formally inconsistent under each side's stated modelling assumptions, and the disagreement is unresolved at the time of writing (Table 2). We take no side; for this paper, the tension is what makes the system valuable as a target. The MTH requires a genuine IMBH (P2), so the Bañares-Hernández scenario, if confirmed, falsifies the ω Cen application outright, one of several clean kill switches catalogued in Section 7. LISA can settle the question definitively, contingent on a suitable source being in-band during the mission: a single IMBH undergoing a compact-object inspiral yields resolvable extreme- or intermediate-mass-ratio-inspiral (EMRI/IMRI) signals with percent-level mass and spin measurement, whereas a remnant swarm yields a qualitatively different gravitational-wave signature (Amaro-Seoane 2018; Babak et al. 2017; Colpi et al. 2024).

The contingency deserves emphasis, because the per-cluster IMRI rate for a ~10⁴ M_☉ hole is uncertain by orders of magnitude, and the plausible outcome of a 4–10 yr mission is that no inspiral is caught in-band, in which case the gravitational-wave branch of Section 7 returns "inconclusive" rather than a verdict (Fig. 6, silence branch). Two mitigations exist. The dense fast-star environment resolved by Häberle et al. (2024a) raises the prior on close compact companions relative to a field IMBH, though it does not remove the rate uncertainty. More important, an inspiral is not the only LISA channel: Strokov et al. (2022) show that a Galactic-cluster IMBH can reveal itself through Doppler modulation of the gravitational-wave signal of an orbiting stellar-mass binary, a continuous signature that requires no merger event during the mission. This channel constrains the mass, though not the spin, so the decisive T5 measurement remains inspiral-contingent.

One element of the predicted dark population has now been observed directly. Whitaker et al. (2026) report the astrometric detection of a 4.46^+1.22_−1.01 M_☉ black hole with reported orbital elements P = 94 yr, e = 0.72, a = 31 AU and a ~0.8 M_☉ main-sequence companion, from HST astrometry spanning 2002–2023 combined with JWST imaging: the first confirmed stellar-mass black hole in ω Cen, and the first astrometric detection of one in any globular cluster. (We note without resolution that the reported elements are in mild internal tension: Kepler's third law with a = 31 AU and M_tot ≈ 5.3 M_☉ gives P ≈ 75 yr, ~25 per cent below the reported period; reconciliation presumably lies within the quoted uncertainties on a and the masses.) The detection confirms that the cluster forms and retains stellar-mass black holes, the population of which both sides of the mass tension require (~10⁴ such remnants in the extended-component scenario; a formation reservoir in the IMBH-growth scenario), and it anchors the low-mass end of the central mass budget with an object whose parameters are measured rather than modelled.

5.3 Electromagnetic silence

Whatever occupies the centre of ω Cen, it is extraordinarily dark. The deepest radio observation of any globular cluster (~170 h with ATCA at 7.25 GHz, reaching an rms of 1.1 μJy beam⁻¹) detects nothing at any proposed cluster centre, bounding the accretion efficiency of a putative IMBH at ε ≲ 4×10⁻³ of the Bondi rate (3σ; model-dependent, with ≈1 dex of systematic from the fundamental-plane conversion) (Mahida et al. 2026), the deepest point yet in the radio-limit framework established for globular clusters by the MAVERIC survey (Tremou et al. 2018). JWST NIRCam and MIRI photometry of the central field likewise finds no source with the spectral energy distribution of an accreting IMBH, with limits most constraining at the low-mass end of the allowed range (Chen et al. 2025). The X-ray channel, the standard probe of quiescent accretion, agrees: a ~291 ks Chandra exposure detects no central point source, limiting the unabsorbed luminosity to L_X(0.5–7.0 keV) ≲ 1.6×10³⁰ erg s⁻¹, an Eddington ratio of ≲10⁻¹² for a 10⁴ M_☉ hole (Haggard et al. 2013). To our knowledge, no dedicated technosignature search of ω Cen has been conducted at any wavelength, although the commensal opportunity is unusually rich: ω Cen is a flagship MeerKAT pulsar-timing target, so every timing session is a potential commensal SETI epoch on the cluster for Breakthrough Listen's MeerKAT backend; the first dedicated globular-cluster SETI survey (five northern clusters with FAST; ω Cen is inaccessible from FAST's latitude — Huang et al. 2026) demonstrates both the feasibility and the current emptiness of this niche, and a Gaia-based phase-space anomaly metric over 79 Galactic globular clusters, in which NGC 5139 ranks among the dynamically most complex systems proposed for technosignature-oriented follow-up (Huang, Tao & Zhang 2026), provides independent validation for treating globular-cluster anomalies as search targets.

The logic matters here: the MTH predicts electromagnetic silence (P3–P4), but silence is equally consistent with, and more parsimoniously explained by, a quiescent, gas-starved compact object in a relaxed, gas-poor old cluster, which we adopt as the null hypothesis H₀ throughout. Silence cannot confirm the MTH; only the discriminating residues of P4 can separate the hypotheses (Section 7).

5.4 Why not Sagittarius A*?

A natural objection: if bigger is better, the Galactic Centre hosts a 4.3×10⁶ M_☉ hole (GRAVITY Collaboration 2022; Event Horizon Telescope Collaboration 2022) with abundant fuel. Three of the four selection criteria of Section 3.1 disfavour it; the first is thermodynamic, the second and third strategic (per the register of claim 1, Section 1.1). First, the storage and erasure advantages saturate at IMBH scale: nothing a maximizer needs scales usefully beyond ~10^4–5 M_☉, while hazards do. Second, the Galactic Centre is the most dynamically violent environment in the Galaxy (ongoing star formation, supernovae, magnetar flares, stochastic accretion flares, and a dense population of perturbers) the opposite of a stable substrate for Gyr-scale infrastructure; ω Cen's relaxed core offers the same physics in a far quieter dynamical environment. Third, the claim structure matters, in the era-relative form of criterion 3: the Galactic Centre's gas and stars are the future fuel of natural astrophysics and of any fusion-era competitor, whereas a globular cluster's low-mass reservoir is uncontested by fusion-era economics and contested only among computation-maximizing lineages, the population P1 already conditions on; the premium therefore goes to early arrival rather than to contest avoidance. The MTH thus predicts that the preferred class is IMBHs in dense old clusters rather than supermassive holes, a distinctive and testable preference, since it directs attention at objects mainstream SETI has never examined.

6. A staged exploitation architecture

We model the migration as five phases (Fig. 5), parameterized for a civilization departing a planetary system ~5 kpc from ω Cen.

Phase 1 — Scouts. Gram-scale beamed-sail probes at 0.1–0.2 c (Lubin 2016), with photon-braking and magnetic-sail deceleration into the cluster halo; transit ~10⁵ yr. Objectives: resolve the IMBH-versus-swarm question in situ, map the rocky-body inventory, and emplace a deceleration relay for following waves. External signature: none detectable at interstellar range.

Phase 2 — Self-replicating industry. Kilogram-scale seed factories bootstrap exponentially from asteroidal material, following the NASA self-replicating-systems concept (Freitas & Gilbreath 1982); decades to centuries to 10³⁺ factory units and a relay laser. Signature: waste heat of order early-industrial — far below detectability.

Phase 3 — Compute swarm. The main payload (substrate-independent minds, by this stage the default cargo; cf. Smart 2012) arrives and assembles a free-flying compute swarm. While the hole is being fed, the swarm's inner working boundary sits at ≳10² r_g (~3×10⁶ km at 2×10⁴ M_☉): the companion infrastructure analysis (Paper E) finds that accretion-flow erosion excludes hardware inside ~30 r_g of a fueled hole, and differential Lense–Thirring precession already excludes rigid formations at 10² r_g, so the swarm must be free-flying there in any case. Controlled star-lifting of brown dwarfs establishes a thin sub-Eddington disk; BZ extraction begins at low spin. Tiered orbits allocate clock rate (Section 4.4), though for an operating (fueled) system the stable dilation on offer at the 10² r_g working boundary is modest, dτ/dt ≈ 0.985; the deep-orbit clock rates of Fig. 4 become available only to dormant or archival elements around an unfueled hole. Signature: faint, soft accretion luminosity — the one phase in which the system would be conventionally observable; at ω Cen, current limits already exclude an active Phase 3 fed above ~4×10⁻³ of the Bondi rate (Mahida et al. 2026) or radiating above ~10⁻¹² of Eddington (Haggard et al. 2013; Chen et al. 2025).

Phase 4 — Spin-up. Sustained prograde feeding (~10^4–5 stars over ~10⁸ yr; Section 4.1) drives a_★ → 0.9–0.998; the ISCO migrates inward by a factor ~5 and jet efficiency crosses unity in MAD episodes; the fueled swarm holds its ~10² r_g working boundary throughout (Paper E). Signature: secular cluster-core depletion; episodic jet activity if imperfectly managed; high spin as a permanent record. We flag the strongest hidden premise of the whole architecture here: Phases 3–5 presuppose institutional or goal stability over 10⁸ yr, longer than mammalian evolutionary history, and stellar feeding requires active orbit-shaping of individual stars with non-trivial delta-v budgets. We know of no principled argument that either is achievable; the architecture is offered conditional on both.

The delta-v can at least be priced to order of magnitude. Delivering a star inward from a near-circular cluster orbit requires removing nearly all of its orbital angular momentum; the per-star impulse is of order the local orbital speed, tens of km s⁻¹ across the central 1–10 pc and growing with the radius of the ~10-pc reservoir that the fuel census of Section 3.1 requires. The energy is not the obstacle (binding energy is released on the way down); the angular momentum is. Two payment schemes exist: engineered orbit-shaping (gravitational-assist sequencing among cluster stars, or beamed-momentum tugs), or reliance on natural loss-cone refilling, which resonant relaxation drives near the influence radius (Rauch & Tremaine 1996). The natural channel supplies stars at zero actuation cost but on a schedule the civilization does not set; the engineered channel buys scheduling control at a budget of order 10² km s⁻¹ of imparted delta-v per solar mass delivered. A full account (which stars, in what order, at what actuator cost) has not been produced and remains the largest quantitative gap in this section.

Phase 5 — Endpoint. Near-extremal spin; waste entropy disposed across the horizon (Section 4.2); residual stellar population dispersed or consumed. During fueled operation the swarm computes at the ≳10² r_g working boundary (dτ/dt ≈ 0.985); if the system instead enters a dormant, unfueled archival mode, elements can descend to the near-ISCO orbits of Fig. 4 and bank the full ~11:1 stable dilation. The system is nearly, but not perfectly, thermodynamically silent: transport losses in delivering waste entropy to the horizon impose a waste-heat floor L_waste ≳ 10⁻⁴ P_comp (Paper E), so current JWST mid-infrared limits already bound the computational throughput of any operating Phase-5 system at ω Cen to P_comp ≲ 10^3–4 L_☉; there is no radio leakage, and the horizon temperature is in the picokelvin range (Eq. 4). The sole conjectured emission channel is burst-mode: if intractable computations are delegated to manufactured micro black holes per Dvali & Osmanov (2023), their evaporation yields high-energy neutrino and gamma-ray transients. We note for completeness that the formation of micro black holes from focused radiation may be blocked by Schwinger-limit pair production (Álvarez-Domínguez et al. 2024; Breit & Wheeler 1934; Schwinger 1951); this conclusion is contested (Loeb 2024), and the MTH does not depend on the channel — it affects only the strength of prediction T6 below.

7. Falsification framework and observational program

We define the competing hypotheses explicitly, then the tests.

H₀ and H₂ predict identical electromagnetic appearances today (by design, since P3–P4 entail silence) so electromagnetic non-detections cannot distinguish them. They diverge on dynamical and high-energy observables. Table 3 states six tests with thresholds, instruments, and timelines; Fig. 6 arranges the decisive subset as a decision tree.

Three features of this matrix deserve emphasis. First, it contains genuine kill switches: T3 falsifies the ω Cen application outright, and T5 falsifies the only exploitation model we have offered; T4 is a demotion rather than a kill, removing ω Cen from the top of the P2 selection ranking while leaving a still-substantial power budget in place. The MTH cannot survive a confirmed remnant swarm or a non-spinning IMBH, except as vacuous speculation about other systems. Second, the LISA spin measurement is among the most informative numbers obtainable this generation (if an in-band inspiral delivers it; Section 5.2), though both the natural-spin null and the expected yield must be stated carefully. Natural formation channels span the spin range (Reynolds 2021): runaway stellar collisions build IMBHs near 10⁴ M_☉ without requiring rapid rotation of the remnant (Fujii et al. 2024), and incoherent minor-merger growth random-walks the spin toward a broad distribution centred near a_★ ≈ 0.2–0.5 (Reynolds 2021), so the T5 trigger a_★ < 0.1 occupies a small tail of the natural prior and the most probable natural outcome lands in the uninformative middle branch of Fig. 6. A measured a_★ < 0.1 still fires T5 cleanly; the hedge concerns how likely nature is to deliver a verdict, not what the verdict would mean. The paper's own account of ω Cen's origin (Section 5) is, however, a gas-rich dwarf-galaxy nucleus, and an IMBH grown there by coherent disk accretion generically reaches high spin naturally; because Blandford–Znajek spindown at ambient fueling operates on ~4×10¹¹-yr timescales (Paper E), such natal spin survives to the present. A measured a_★ ≳ 0.9 is therefore supporting evidence rather than a diagnostic residue on its own: the discriminating observation is the conjunction of high spin, electromagnetic silence far below the ambient Bondi supply, and the regulation signature of T1 (P4a–b together). EMRI parameter estimation at LISA delivers spin to better than percent precision for favourable systems (Babak et al. 2017; Amaro-Seoane 2018). Third, the program is cheap: T1–T2 are archival or piggyback analyses; T6 requires only a pointed monitoring program on an instrument already built for the southern sky (Adrián-Martínez et al. 2016; KM3NeT Collaboration 2025), following the high-energy SETI logic of Lacki & DiKerby (2025) and the pipeline practices of standard point-source searches (IceCube Collaboration 2020); the partially built ARCA array has already demonstrated discovery-class capability with the ~220-PeV event KM3-230213A, the most energetic neutrino yet observed (KM3NeT Collaboration 2025); and T3–T5 are free by-products of LISA's planned EMRI science (Colpi et al. 2024).

The T6 burst criterion must clear the atmospheric-neutrino background, and an order-of-magnitude estimate shows it does under the stated cuts. Full-detector ARCA is expected to collect of order 10³ up-going atmospheric muon-neutrino events per year above 10 TeV over the full up-going sky (effective areas and atmospheric fluxes from the KM3NeT 2.0 letter of intent; Adrián-Martínez et al. 2016). A 1°-radius cone subtends ~10⁻³ sr, a fraction ~1.5×10⁻⁴ of the up-going hemisphere, giving a source-cone rate of ~0.15 events yr⁻¹, i.e. λ ~ 5×10⁻⁹ s⁻¹. The Poisson expectation in a 10³ s window is then μ ~ 5×10⁻⁶, so the probability of an accidental ≥3-fold multiplet per window is μ³/6 ~ 2×10⁻¹⁷; a decade of livetime contains ~3×10⁵ independent 10³ s windows, for an expected false multiplet count of ~10⁻¹¹ per decade. The 1° cone is itself deliberately conservative: ARCA's track angular resolution above 10 TeV is ~0.1–0.2°, so a resolution-matched cone carries a background lower by a further factor of 25–100. The criterion is background-free by many orders of magnitude even allowing generous uncertainties in the effective area and a trials factor for scanning window durations; the practical limit on T6 is exposure, not background. A dedicated ω Cen technosignature campaign would be the first of its kind for any globular cluster beyond the pilot survey of Huang et al. (2026), which could not observe ω Cen.

7.1 What would count as support

Symmetry requires stating the confirmation side. The MTH gains support only from conjunctions that H₀ finds awkward: (i) a LISA-confirmed IMBH with a_★ ≳ 0.9 in conjunction with Gyr-scale gas starvation and the regulation signature of T1, since high spin alone admits the natal-disk explanation above; (ii) repeated >5σ neutrino bursts from the core with hard spectra and no electromagnetic counterpart, matching the Dvali–Osmanov phenomenology; or (iii) a measured low-mass mass-function slope in the central 0.1 pc lying below the González Prieto et al. (2025) model envelope at >3σ (oMEGACat photometry reaches the relevant depth), the concrete form of the P4c depletion residue. No single line, including all three jointly, would constitute proof of technology; they would constitute an anomaly stack justifying escalated scrutiny. Conversely, we commit in advance: if LISA delivers T3, T4, or T5, the ω Cen application of the MTH should be retired without special pleading.

8. Discussion: objections and limits

Parsimony. The MTH posits extraterrestrial intelligence; H₀ posits nothing. By any reasonable prior the null is favoured, and we have structured every comparison accordingly. The defensible claim is that the MTH is cheap to test relative to its information value, not that it is probable: it concentrates the diffuse question "where is everybody?" onto a handful of named objects and a decade-scale instrument schedule, and its decisive observables (IMBH reality, mass, spin) are independently first-rank astrophysics that will be measured anyway.

The anthropic objection. If P1–P2 captured all civilizations, our own existence as a young, loud, planet-bound species is unremarkable; the MTH explains the silence of the old, not the existence of the young. It is therefore not undermined by our own counterexample, but neither can it explain why no expansionist civilizations are visible (cf. Hanson et al. 2021): if migration is optional, loud lineages should still exist somewhere. The defensible position is that the MTH thins the expected population of loud civilizations by removing its most capable members, sharpening rather than fully dissolving the paradox; full dissolution requires either high migration compliance or supplementary rarity from conventional Drake-equation factors.

Goal stability over 10⁸ years. Phase 4 presupposes coherent purpose across timescales that dwarf all institutional experience. We flagged this as the architecture's largest unargued premise (Section 6). One partial mitigation: the architecture's payoff structure is front-loaded (Phase 3 already yields a substrate orders of magnitude beyond planetary computing), so a lineage that fragments mid-program still leaves durable traces, but fewer than we once supposed. The companion analysis (Paper E) finds that an abandoned swarm is not preserved: collisional cascade grinds it to debris within 10²–10³ yr, and the debris drains into the hole. The durable residues of incoherence are the spin acquired before fragmentation and, if Phase 4 ran long enough, the core depletion it caused; the hardware itself leaves no fossil. The observational program is robust to civilizational incoherence only through those two channels, which is a further reason the dynamical tests (T3–T5) carry the weight.

Tidal and radiative survivability at the ISCO. At 2×10⁴ M_☉ the tidal field at the Schwarzschild ISCO is 2GM/r_ISCO³ ≈ 1 s⁻²: a 10-m node experiences a benign ~1 g differential, while kilometre-scale rigid structures would face ~10² g — one reason the architecture assumes a swarm of small free-flying nodes rather than a monolithic platform. Radiation from even a managed accretion disk is the harsher constraint, and motivates the tiered-orbit design and sub-Eddington feeding discipline assumed in Section 6. We have not engineered these systems in detail and do not pretend to; the claim defended is the thermodynamic gradient (P2), not any specific machine.

Why has nothing arrived here? A migration hypothesis must explain why migrators' probes are not conspicuous in every system, reviving Hart (1975) and Tipler (1980). The MTH answer is economic: for a computation-maximizer, planetary systems are at most transit infrastructure rather than destinations; the Galaxy's uncollected starlight (an integrated stellar luminosity of (1–2)×10³⁷ W) dwarfs any single system's output by ten orders of magnitude, and yet (Section 4.5) the marginal value of any outward claim is dominated by deepening the home gravity well. Quiet, minimal, purpose-built transit, rather than occupation, is the predicted footprint, consistent with the null results of artefact SETI to date (Wright et al. 2022). Ivliev (2026) presses the opposite conclusion: once autonomous machine industry matures, outward expansion becomes too cheap and too useful for any civilization to refuse, and the attractor is quiet distributed expansion rather than concentration. We accept the premise that expansion is cheap, and we concede that for an undiscounted maximizer of total integrated computation Ivliev's inference goes through, since controlled mass grows as t³. The disagreement localizes to the auxiliary assumptions of Section 4.5: under temporal discounting, latency-bound unified computation, or bounded planning horizons, expansion does not compete with concentration in yield per unit of controlled resource, and it is civilizations satisfying at least one of those conditions that the MTH captures. The two proposals are nonetheless observationally adjacent, since both predict a Galaxy free of conspicuous macro-engineering, and they diverge where the MTH is testable: Ivliev's filter predicts no privileged loci, while the MTH concentrates its residues on a short list of named systems.

The kugelblitz weak link. The only positive high-energy signature we predict (T6) inherits the controversy over micro-black-hole formation from radiation (Álvarez-Domínguez et al. 2024; Loeb 2024). We therefore weight T6 as the cheapest test, not the strongest: its null closes a speculative channel; its detection would be extraordinary but stands or falls with Dvali–Osmanov physics, not with the MTH core.

Scope of the ω Cen bet. The MTH is a selection theory over a class; ω Cen is its highest-ranked accessible member, not its definition. Falsification at ω Cen (T3, or the ranking demotion of T4) retires the flagship application and substantially weakens the hypothesis (the Galaxy's best candidate failing is evidence about the class) but formally the theory survives in 47 Tuc, M54, and extragalactic nuclear clusters. We accept the methodological hazard this creates (unfalsifiability by retreat) and therefore bind ourselves to the class-level prediction: if no Galactic globular-cluster IMBH with a_★ ≳ 0.9 exists, the MTH is wrong for the Milky Way, a statement LISA-era gravitational-wave astronomy can settle.

9. Conclusion

We have argued, first as a matter of established physics, that rapidly spinning massive black holes in dense old stellar clusters constitute the global optimum among present-day environments for long-term computation (by factors of ~10² in energy per unit fuel, ~10⁹ in continuous power, a realized 10⁶–10⁹ in entropy-disposal cost once delivery overheads are charged against the ~10¹² floor-to-floor ratio (Section 4.2), and unbounded factors in archival density) and second, as an explicitly speculative hypothesis, that this gradient acts on the oldest technological civilizations as an attractor whose operation would look, from outside, like the silence we observe. The Macro Transcension Hypothesis inherits the thermodynamic insight of transcension and aestivation while repairing their respective defects: it needs no exit from the universe and no dormancy, and it survives the Bennett–Hanson–Riedel free-energy objection by importing the cold reservoir into the present rather than waiting for one.

Its principal virtue is that it pays its way observationally. The hypothesis selects a named target (Omega Centauri, whose contested 8×10³–5×10⁴ M_☉ central object, perfect electromagnetic silence, and 12-Gyr head start make it scientifically urgent on entirely conventional grounds) and commits to kill criteria that existing and funded instruments will adjudicate: LISA's resolution of the IMBH-versus-swarm question and, above all, its spin measurement; deep accretion and waste-heat limits from JWST and southern radio arrays; and a first-of-its-kind neutrino monitoring campaign with KM3NeT. If the central object proves to be a remnant swarm, a light point mass, or a slowly spinning hole, the hypothesis fails at its flagship and we have said so in advance. If instead the 2030s deliver a massive, gas-starved, near-extremally spinning black hole in the quietest old cluster in the sky, the question this paper poses will have earned the right to be taken seriously.