Related by context. Frequent words. (Click for all words.) 71 aliens 69 extraterrestrial 60 UFOs 60 alien 59 Martians 57 flying saucers 54 outer space 53 UFO 49 Martian 48 interplanetary 47 intergalactic 46 alien invasion 46 flying saucer 46 beings 46 spaceships 46 paranormal 45 asteroid 45 Mars 44 telepathy 44 supernatural 44 Carl Sagan 44 Cylons 44 UFO sightings 43 Red Planet 43 spaceship 42 cannibals 42 sentient 42 antimatter 42 science fiction 42 interstellar 42 creatures 42 Aliens 42 galactic 42 planets 41 psychic powers 41 sci fi 41 Stephen Hawking 41 celestial bodies 41 cosmos 40 humanoid 40 robots 40 supernatural powers 40 mutants 40 droids 40 humans 40 monsters 40 psychics 40 zombies 40 Autobots 39 ghosts 39 Alien 39 asteroids 39 alternate universe 39 Saturn moon 39 X Files 39 Na'vi 38 werewolves 38 planetary 38 superheroes 38 quantum physics 38 cavemen 38 spies 38 undead 38 cyborg 38 comet 37 psychic 37 astrophysicists 37 solar flares 37 vampires 37 cosmic 37 teleportation 37 Deep Impact 37 creature 37 orbiting 37 Skynet 37 hauntings 37 Mars rover 37 astrophysicist 37 critters 37 hobbits 37 telepathic 37 spy satellites 37 cosmology 36 chipmunks 36 planet 36 paranormal activity 36 Planetary 36 martian 36 demonic 36 comets 36 creationists 36 guardian angels 36 dinosaurs 36 Bigfoot 36 Mars Rover 36 cosmic rays 36 neutrinos 36 malevolent 36 spacecraft 36 Mossad agents 36 astronomers