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 Pandemics Ecosystem collapse Asteroid Capitalism Super Tsunami Antimicrobial resistance Genetic modification Neobiota Ozone depletion Hypersonics Coronavirus Geoengineering Nationalism Superintelligence Totalitarianism Unknown unknowns