2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/83937A proof is developed from first principles, independent of general relativity and of thermodynamics, that there exists a threshold acceleration above which radiation (real particle creation) from the vacuum must occur. The radiation is not expected to follow a Planckian distribution. PACS Codes: 03.65.Bz 04.70.-s 26.35.+cv. 1.5 adds minor clarification on nonthermal distributionGeneral Physicstext