The Milky Way is home to millions of potentially habitable planets – and approximately four of them may harbour evil alien civilisations that would invade Earth if they could. A new paper, which has not yet been peer-reviewed, poses a peculiar question: what are the odds that humans could one day contact a hostile alien civilisation that’s capable of invading our planet? To answer this, lead scientist Alberto Caballero, a doctoral student in conflict resolution at the University
