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