Traces of a Serial Planetary Killer: Forensic Evidence of Repeated Cosmic Impacts as the Primary Driver of Earth's Major Extinction Events

This work presents a comprehensive forensic analysis of Earth's five major mass extinction events, proposing that cosmic impacts were the primary trigger for each catastrophe. Using a multi-proxy approach that integrates geochemical signatures, stratigraphic patterns, structural evidence, and temporal correlations, we reconstruct the "crime scenes" of planetary-scale catastrophes spanning 445 million years of Earth history. We introduce the methodology of Forensic Planetology, applying investigative principles to geological evidence to establish causal links between impacts and extinctions. For each of the "Big Five" extinctions (Ordovician-Silurian, Late Devonian, Permian-Triassic, Triassic-Jurassic, and Cretaceous-Paleogene), we present:(1) Direct evidence: iridium anomalies, shocked quartz, spherules, and crater structures(2) Circumstantial evidence: extinction selectivity patterns, carbon isotope excursions, and oceanic anoxia(3) Temporal correlations: precise radiometric dating linking impact events to extinction horizons(4) Mechanistic pathways: how impact-triggered environmental cascades drove biotic collapse The analysis reveals a consistent pattern: impacts exceeding critical thresholds (~10 km diameter) trigger multi-stage environmental catastrophes including immediate devastation, prolonged "impact winter," ocean acidification, and sustained volcanism (via the Antipodal Bullet mechanism). We identify specific "smoking guns" for each event and propose testable predictions for confirming impact origins where evidence remains incomplete. This work establishes a unified framework for understanding mass extinctions as impact-driven phenomena and provides critical insights for planetary defense strategies, demonstrating that Earth has been the repeated target of a "serial planetary killer" throughout geological time. As an independent researcher, I welcome collaboration with members of the scientific community who find value in this work.Researchers registered as arXiv endorsers in Geophysics (physics.geo-ph), Astrophysics (astro-ph.EP), or related fields who are willing to support submission of this paper to arXiv are invited to contactthe author at [email protected]. https://orcid.org/0009-0006-1089-9023