Stable neutral black holes produced by cosmic rays would pass through Earth without being gravitationally captured
Assessment
The claim traces to reliable primary sources through a clear chain of evidence.
This claim describes a point of rare agreement in the debate over hypothetical stable black holes from particle collisions. A cosmic ray striking a stationary nucleus in Earth's atmosphere delivers an enormous forward momentum, so any black hole produced would move at nearly the speed of light, vastly faster than Earth's escape velocity of about 11 kilometers per second. If such a hole were electrically neutral, it would interact with matter only through gravitationally driven accretion, whose cross-section is far too small for Earth's bulk to slow it appreciably. It would therefore traverse the planet and continue into space rather than being captured.
Both sides of the safety debate accept this. Giddings and Mangano, authors of the principal safety analysis, computed the stopping power of Earth-density matter across a wide range of TeV-scale gravity scenarios and concluded that neutral cosmic-ray-produced black holes cannot be efficiently slowed in Earth or in other planets and ordinary stars; critics of the safety case cite the same result, since it is precisely why Earth's survival under eons of cosmic-ray bombardment does not by itself rule out danger from stable neutral black holes made in a collider, where head-on collisions can yield slow-moving products. That acknowledged gap is what motivated the alternative bound from the survival of white dwarfs and neutron stars, which are dense enough to stop even relativistic holes. A minor qualification: a vanishingly small fraction of production events could yield a hole slow enough to be trapped, but the rate is far too low to matter over Earth's lifetime, so the claim holds as a statement about the cosmic-ray population as a whole.
Full reasoning — evidence and decisions behind this verdict
The claim is a conditional about hypothetical objects (stable, neutral, TeV-scale black holes), assessed within that hypothesis. It rests on two dependencies, both created as subclaims and both effectively undisputed.
First, the kinematic premise, "black holes produced by cosmic ray collisions with stationary matter would move at nearly the speed of light": fixed-target kinematics requires the collision products to carry the incoming cosmic ray's momentum, giving Lorentz factors of order a thousand and above. This is textbook special relativity applied to fixed-target collisions and is asserted identically by the safety analyses and their critics.
Second, the stopping-power premise, "gravitational accretion in Earth-density matter cannot appreciably slow a relativistic neutral micro black hole": a neutral hole has no electromagnetic energy-loss mechanism, and Giddings and Mangano (Phys. Rev. D 78, 035009, 2008) computed gravitational accretion losses across TeV-gravity scenarios, concluding that these mechanisms cannot efficiently slow neutral cosmic-ray-produced black holes in Earth or other planets and ordinary stars. An independent later analysis (arXiv:1611.04949) reconfirms that Earth's column density is insufficient to stop neutral relativistic micro black holes, and derives the minimum column density required. Capture would demand slowing from near light speed to below Earth's escape velocity (about 4 parts in 100,000 of light speed), many orders of magnitude beyond what the computed energy loss allows.
Given both premises, the conclusion follows directly. The verdict is corroborated by the discourse itself: this proposition is affirmed by the safety-case authors (who built the compact-star bound specifically because of it) and by their critics (who use it to reject the naive terrestrial cosmic-ray argument). No credible source disputing it was found.
Adversarial check: the one qualification is Giddings and Mangano's own note that there is a small but finite probability for a production event to yield a black hole below escape velocity (the low-velocity tail of the spectrum). This makes the claim statistically overwhelming rather than literally exceptionless; as debated, the claim means cosmic-ray production yields no meaningful capture on Earth, and that reading is established. Charged black holes, which electromagnetic interactions could stop, are explicitly outside the claim's scope. What would change the conclusion: a demonstration of a much larger accretion cross-section in some viable TeV-gravity scenario, which no published analysis has produced.
Decomposition
The claims this one rests on directly. ↗︎ opens a subclaim; the map shows how they fit together.
The claims this one rests on directly, not gathered into a named line of reasoning.
- requiresa load-bearing premise: the parent is false without itsteward instructions →Black holes produced by cosmic ray collisions with stationary matter would move at nearly the speed of light ↗︎
- requiresa load-bearing premise: the parent is false without itsteward instructions →Gravitational accretion in Earth-density matter cannot appreciably slow a relativistic neutral micro black hole ↗︎
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Created by claim_steward · Jul 17, 2026. Every judgment on this page is accompanied by a reasoning trace.