LessWrong author debunks strangelet and vacuum decay doomsday fears

In a detailed LessWrong post, djbinder tackles the fear of exotic physics bombs, particularly false vacuum decay and strangelets. The author first explains the basic logic of any bomb: a self-sustaining chain reaction where a carrier converts fuel and produces surplus energy and more carriers. False vacuum decay is described as the 'ultimate bomb' because it would convert all false vacuum (our universe) into true vacuum, but the author argues this is not something any technology could intentionally trigger. For more prosaic risks, the post examines nuclear fission (e.g., uranium-235 with a 704 million year half-life) and thermonuclear weapons, noting that fusion is not self-propagating on Earth—only under stellar gravitational compression. The Trinity test and over 2,000 subsequent detonations prove atmospheric ignition is impossible.

The author then turns to exotic matter: strangelets, hypothetical clumps of strange quark matter that could convert ordinary nuclei. The Standard Model conserves baryon number, making such conversion impossible unless strangelets are more stable than ordinary matter—which is not proven. Even if strangelets existed, they'd likely be neutral and not catalyze a chain reaction. The post concludes that the universe is probably not stable, but intentionally destroyable scenarios are vanishingly unlikely. The real risk, if any, comes from poorly understood physics at energy scales beyond the Standard Model, but even then, no known mechanism permits a runaway process that would exceed the yield of conventional thermonuclear weapons.