Underground city Political themes Adhocracy Anarcho-capitalism Capitalism Evil corporation Megacorporation Neo-feudalism Cognitive liberty Dystopias and utopias Environmental pollution Overpopulation Technological utopianism Totalitarianism Galactic empires Government by algorithm Legal personality Libertarianism Mass surveillance Mind reading and mind control National security state Post-scarcity economy Socialism Nanosocialism Technoethics Bioethics Technophobia Techno-progressivism Terrorism Bio-terrorism Eco-terrorism Totalitarianism vs. Libertarianism Technologies Artificial gravity Artificial intelligence Asteroid mining Astronomical engineering Brain–computer interface Cloaking device Emerging technologies Robots Self-replicating machines Simulated reality Star lifting and stellar engineering Stasis device Total conversion as energy source Mecha Megascale engineering and planetary engineering Megastructures Dyson sphere Molecular manufacturing and Nanotechnology Molecular assembler Alien technology Virtual reality, mixed reality, augmented reality Infosphere Metaverse Weapons in science fiction Travel Accidental travel Colonization of other planets, moons, asteroids, etc. Embryo space colonization Generation ship Interstellar ark Uploaded astronaut Terraforming Space exploration Interstellar travel/Starships Faster-than-light travel and communications Hyperspace Slipstream Warp drives Wormholes Ansibles Close to light speed Bussard ramjets Ursula K. Le Guin's NAFAL ships, and the Twin paradox Much slower than light Generation ship Sleeper ship Space stations Teleportation Teletransporter Time travel Alternate history: time travel can be used as a plot device to explore parallel universes. While alternate history has its own category (see above), it often occurs in time travel stories as well. Alternate future Time loop Travel to the Earth's center Hollow Earth See also Biology in fiction Fantasy tropes Outline of science fiction Protoscience References Science fiction themes