A small planetary body impact simulation shows what would happen if a moon-sized object struck Earth at cosmic velocity. On impact, kinetic energy converts instantly into heat and shockwaves. The crust at the collision point vaporises, ejecting material into space while seismic waves propagate through the mantle. A global firestorm follows as superheated debris re-enters the atmosphere. Oceans near the impact boil, tsunamis radiate across continents, and the atmosphere becomes choked with dust a