Reasoning:
- In interstellar collisions, unlike on the Moon, strangelets produced at any rapidity include some at rest with respect to the galaxy (the two colliding fluxes are isotropic), so no stopping/velocity model is needed — this argument and the lunar one have complementary loopholes.
- A long-lived dangerous strangelet swept into a protostellar cloud would convert its host star, an event resembling a supernova; the observed supernova rate (and absence of anomalous explosion classes) bounds the production probability far below danger for RHIC/LHC-scale programmes.
- Residual assumption: the strangelet must live from production to star formation (~Myr). A strangelet metastable with lifetime between ~1e-7 s (long enough to stop and stabilize at a collider) and ~Myr would evade this bound while remaining dangerous at a collider — the reason the lunar and thermodynamic arguments are still needed alongside it.
Step 6 — validity verdict
approved / checked. Reconstruction — premises: (i) the two colliding interstellar fluxes are isotropic, so produced strangelets populate all galaxy-frame velocities, including near rest — eliminating any stopping/velocity model; (ii) a long-lived dangerous strangelet swept into a protostellar cloud converts its host star in a supernova-like event; (iii) no anomalous stellar-explosion class is observed at the implied rate. Conclusion: production of long-lived dangerous strangelets is bounded far below collider-relevant danger. The one residual assumption (lifetime >= star-formation timescale ~Myr) is stated inside the statement itself, and the body explicitly identifies the complementary loophole (a 1e-7 s-to-Myr metastable strangelet) that this argument does not close — the enthymeme is fully surfaced. Conditional on the premises the modus tollens is valid. Candidate defeater “conversion might not be observable as an explosion” denies premise (ii) rather than the inference, so it is priced downstream. Traced directly.