Workflow · Peer-reviewed physics
Seven tools, one continuous thread: what is a black hole, how does one behave across ten decades of mass, and why does the 7,100 M☉ candidate at the centre of Omega Centauri sit at exactly the most interesting point in every one of these plots? No jargon prerequisites. Each stage links to an interactive calculator.
A black hole's size is set by the Schwarzschild radius: r_s = 2GM/c². For a 10 M☉ stellar-mass black hole, that's about 30 km — the size of a city. For a 10⁹ M☉ supermassive black hole, it's 3 billion km — twice the orbit of Pluto.
The counterintuitive property: mean density drops as mass increases. A stellar-mass black hole is denser than an atomic nucleus. The most massive known black holes are less dense than water. The ω Cen candidate at ~7,100 M☉ has a density between these extremes — roughly that of lead.
At the event horizon of a stellar-mass black hole, the tidal force across a human body exceeds 10¹⁰ g. Nothing survives. But for sufficiently massive black holes, the tidal force at the horizon is gentle enough to pass through — the "spaghettification" happens much later, near the singularity.
The critical mass for a 1.8m observer tolerating 10g: approximately 437 M☉. The ω Cen IMBH at any value in the 6,000–8,200 M☉ window exceeds this by an order of magnitude. You would survive the horizon crossing without noticing it.
Close to a black hole's event horizon, time runs more slowly relative to a distant observer. At exactly the horizon, coordinate time stops entirely — a falling observer appears frozen to an external viewer. This is gravitational time dilation, predicted by general relativity and confirmed in multiple settings.
For an observer hovering just above the horizon of the ω Cen IMBH, each second of proper time corresponds to many hours of external time. The time-dilation tool lets you explore this gradient as a function of distance from the horizon.
The Event Horizon Telescope imaged the shadows of M87* and Sgr A* — two of the largest black holes on the sky. The photon capture region casts an angular shadow of diameter θ ≈ 5.2 GM/(c²d). For M87* at 16.8 Mpc, that's ~42 microarcseconds, barely within EHT's reach.
For the ω Cen IMBH at 5.2 kpc, the mass is 6,000× smaller and the distance is 3,200× smaller — the shadow works out to only ~0.17 μas, about 150 times below EHT resolution. No existing or planned radio telescope can resolve this shadow.
Real black holes spin. The Kerr metric describes a spinning black hole characterised by mass M and spin parameter a (0 = Schwarzschild, 1 = maximally spinning). Spin creates an ergosphere — a region where spacetime itself is dragged around so fast that nothing can remain stationary.
The Kerr geometry tool lets you explore how the inner and outer horizon, ergosphere, and innermost stable circular orbit (ISCO) change with spin. For the ω Cen IMBH, the spin is unknown — but the ergosphere radius for maximum spin is about 14,000 km.
Hawking radiation is a quantum effect: black holes are not perfectly black but emit thermal radiation with temperature T_H ∝ 1/M. For stellar-mass black holes, this temperature is far below the cosmic microwave background (~2.7 K) and evaporation takes longer than the age of the Universe. For microscopic black holes, it is violent.
The ω Cen IMBH at 7,100 M☉ has a Hawking temperature of ~8 × 10⁻²³ K — completely unmeasurable — and an evaporation time of ~10⁷⁶ years. Hawking evaporation is cosmologically irrelevant for this object, but the tool makes the scaling vivid across the mass range.
Having toured the physics, return to the observational question: does the IMBH exist at all? You have now seen that a 7,100 M☉ black hole at 5.2 kpc would be survivable to cross, invisible to EHT, with imperceptible Hawking radiation — and yet its gravitational influence on surrounding stars is the strongest signal available.
The Constraint Stacker aggregates all published mass bounds and shows the kinematic–pulsar tension. The Settle the IMBH Question workflow then chains all the tools to build the full observational case. You are now ready for that workflow.
The intermediate mass range — 10² to 10⁵ M☉ — sits at a crossroads in every physical property. Density transitions from super-nuclear to sub-water. Survivability flips from instant death to a gentle crossing. Shadow size passes from near-resoluble to fundamentally inaccessible. Hawking temperature crosses below the CMB floor. None of these transitions happen at M87* or Cyg X-1 — they happen right in the ω Cen IMBH window.
This is why confirming or ruling out the ω Cen IMBH is not just a cluster-dynamics question. It is a test of black hole physics in the one mass range where every physical parameter changes fastest.
Workflow version 1.0 · 2026-06-10 · All tools: Code MIT · Prose CC BY 4.0 · The Omega Centauri Society