Clathrates Nanotechnology Rogue Microbes Space War Stellar Explosion Unknown knowns Supervolcano Paranormal Cyber attack Solar flare Nuclear winter Bio weapons Supernova Known unknowns Electromagnetic pulse Extraterrestrial Climate change Ecosystem collapse Pandemics Antimicrobial resistance Asteroid Capitalism Geoengineering Super Tsunami Superintelligence Genetic modification Neobiota Ozone depletion Hypersonics Coronavirus Nationalism Totalitarianism Unknown unknowns