<p>The stuff of fantasy and science fiction seem more and more like reality as science and technology continue to advance. Why not then look at imaginary worlds to get a glimpse at what tomorrow might be like? Here are 20 realms that have captured our imaginations before, rated by how plausible they might be, from possible to optimistic to hard to imagine to pure fantasy.</p><p> WARNING: Potential spoilers.</p>
<p>The "Star Trek" series is <a href="http://www.livescience.com/3555-reality-check-science-star-trek.html">packed with science and technology</a> that inspired generations of scientists and engineers -- faster-than-light travel, teleportation, beam weapons, universal translators, hologram-based virtual reality and mobile communicators, among others. A number of these have actually, in some form, become reality -- then again, physics apparently stands in the way of <a href="http://www.livescience.com/12328-star-trek-warp-drive.html">warp drives</a>, and despite a great deal of hand-waving, there seems to be little reason that so many aliens look, behave and can mate with humans other than budgetary limits and storytelling purposes.</p><p> Science Rating: Optimistic.</p>
<p>In "Jurassic Park," scientists have <a href="http://www.livescience.com/7810-extinct-animals-resurrected-frozen-samples.html">recreated dinosaurs and other extinct life</a> using cloning techniques and ancient DNA in fossils. When asked, scientists are often skeptical that DNA could survive over such long time periods, much less used to create viable organisms. Still, novelist Michael Crichton did try to make concessions by noting that broken patches of ancient DNA could be filled in with that from other, living animals. [<a href="http://www.livescience.com/3015-crichton-legacy-sci-fi-thrillers.html">Crichton: A Legacy of Sci-Fi Thrillers</a>]</p><p> Science Rating: Optimistic.</p>
<p>In "Star Wars," bionically enhanced characters battle with rayguns and communicate via holograms aboard spaceships over planet-killing weapons of mass destruction. The films <a href="http://www.space.com/8917-star-wars-changed-world.html">have influenced science and technology in real life</a> -- the space-based weapon platforms of the Strategic Defense Initiative debated in the 1980s were derisively called "Star Wars." Still, even more than faster-than-light travel, the biggest stumbling block toward accepting "Star Wars" as possible in reality -- despite a weak nod toward science with microscopic "midichlorians" in people's bodies -- is the notion of the Force as a physical force enabling telepathy, telekinesis and precognition.</p><p> Science Rating: Hard to Imagine.</p>
<p>The back of a closet in the English countryside leads to another world, Narnia, where time passes differently than on Earth and children ally with a talking lion and mythical creatures against a witch armed with magic candy who can turn opponents into stone. The element regarding a portal to another planet where time passes at a different rate does bring science fiction to mind, but to be fair the Narnia series was not meant to be grounded in science.</p><p> Science Rating: Pure Fantasy.</p>
<p>In the future depicted on the TV show "Firefly," humanity migrated from Earth and colonized a system by <a href="http://www.space.com/3993-scientist-calls-mars-terraforming-target-21st-century.html">terraforming</a> (making livable) its many planets and moons. Divides between rich and poor and a civil war lead many to live on inhospitable worlds, often relegated to possessing only comparatively primitive, Old West-level technology. The show told science fiction without robots, aliens and faster-than-light drives, with only a few rare fantastic elements, such as telepathy. The system also stretches the imagination somewhat with a system composed of five stars, dozens of planets and hundreds of moons, devised to enable stories spanning many worlds happen using only slower-than-light drives. [<a href="http://www.livescience.com/16214-implications-faster-light-neutrinos.html">Warped Physics: 10 Effects of Faster-Than-Light Discovery</a>]</p><p> Science Rating: Optimistic.</p>
<p>A whirlwind takes Dorothy to a land with talking scarecrows, lions and tin men, where she must travel down a yellow brick road to an emerald city and contend with witches. Interestingly, the process by which the Tin Woodman went from a biological to a mechanical existence is reminiscent of roboticist Hans Moravec's proposal to "upload" brains to computers, essentially by replacing one neuron at a time with microchips that can perform the same functions. Still, the <a href="http://www.livescience.com/6802-monkeys-bananas-flying-squirrels.html">flying monkeys</a> seem unlikely.</p><p> Science Rating: Pure Fantasy.</p>
<p>On Middle Earth, humans, elves, dwarves, hobbits and orcs engage in war -- and occasionally marry -- in a medieval-like world populated with giant wolves, eagles, spiders and more fantastical creatures. Scientists have uncovered tiny, big-footed distant relatives of ours that they have whimsically dubbed "<a href="URL">hobbits</a>," and modern humans did coincide and <a href="http://www.livescience.com/9910-humans-neanderthals-mated-making-part-caveman.html">apparently interbreed</a> with other humanoids such as Neanderthals. Researchers nowadays are even developing <a href="http://www.livescience.com/12907-invisibility-cloaks-corner-bts-110217.html">cloaks of invisibility</a> vaguely reminiscent of the power granted by the One Ring. Still, a giant flaming Balrog seems unlikely in real life.</p><p> Science Rating: Pure Fantasy.</p>
<p>In the future depicted in movie series "The Matrix Trilogy," the war between humans and robots has devastated the planet and left humanity enslaved, with our brains connected to a computer-generated imaginary world and our bodies serving merely as power generators. Scientists are slowly making advances in robotics and virtual reality, but appear to be far away from generating a human-level artificial intelligence. Besides, there are much better ways to generate electricity than farming humans. [<a href="http://www.livescience.com/3407-robot-madness-creating-true-artificial-intelligence.html">Robot Madness: Creating True Artificial Intelligence</a>]</p><p> Science Rating: Hard to Imagine.</p>
<p>A team of humans and aliens visit the mind-boggling <a href="http://www.space.com/sciencefiction/larryniven/larry_niven_000210.html">Ringworld</a>, a giant artifact consisting of a ring about 180 million miles wide, roughly as wide as Earth's orbit around our sun, which is spinning fast enough for anything standing on its surface to experience a pull nearly equal that of Earth's gravity. This leads to roughly Earth-like conditions on the entire inner surface of the ring, for a usable area roughly 3 million times the surface of the Earth. There are many fantastic sci-fi elements within, such as telepathy, disintegrators, teleportation, faster-than-light travel, stasis fields and genetic predilections for luck. But the story remains as vigorous with science as possible with the Ringworld and the aliens it depicts. [<a href="http://www.livescience.com/14012-6-weird-facts-gravity.html">6 Weird Facts About Gravity</a>]</p><p> Science Rating: Optimistic.</p>
<p>In Fantastica, known as Fantasia in the film, the young hero Atreyu must fight against a void of darkness known as the Nothing that is consuming the entire world. He is aided in his task by the luck dragon Falkor, and must contend with the wolf-like monster Gmork. Atreyu eventually finds his adventure intertwined with that of Bastian, a boy from our world, who is reading about Atreyu's exploits in the book dubbed "The Neverending Story." The story is pure fantasy, but there are scientists who conjecture that our universe is just a program running on an extraordinarily powerful computer in another universe — that we are, in a sense, virtual. [<a href="http://www.livescience.com/11328-rumor-reality-creatures-cryptozoology.html">Rumor or Reality: The Creatures of Cryptozoology</a>]</p><p> Science Rating: Pure Fantasy.</p>
<p>Pandora is the <a href="http://www.space.com/7709-moons-avatar-pandora.html">habitable and inhabited moon</a> of the fictional gas giant Polyphemus, set in <a href="http://www.space.com/7792-double-sunsets-common-twin-star-setups-mysterious.html">the real Alpha Centauri binary star system</a>. There, humans armed in robotic exoskeletons that seem an homage to those in Robert Heinlein's "Starship Troopers" fight with humanoid aliens over human <a href="http://www.space.com/7842-strip-mining-avatar-planet-paradise.html">strip-mining of a naturally occurring superconductive mineral</a>. In Pandora's <a href="http://www.space.com/8000-alien-plants-twist-world-avatar.html">lush jungles</a>, a remote-controlled puppet operated by a handicapped man, and which seems reminiscent of Robert Heinlein's "Waldo," is also used to deal with the natives. Director James Cameron, once the president of his high school science club, overall <a href="http://www.space.com/7698-real-science-avatar.html">tried hard to get the science right</a>, although he admittedly used a bit of poetic license -- it's hard to imagine an alien naturally evolving the physique of a supermodel.</p><p> Science Rating: Optimistic.</p>
<p>The future depicted in "I, Robot" is filled with androids and other robots that follow the famed <a href=" http://www.livescience.com/10478-asimov-law-japan-sets-rules-robots.html">Three Laws of Robotics</a> that science fiction legend Isaac Asimov devised, which are supposed to keep them from hurting others and themselves while serving humanity as best as they can. Scientists are, step by step, developing robots that can walk like humans, which in Japan are being designed to help its growing elderly population. However, robots that can reason largely like humans do have so far proven difficult to invent, much less ones that can <a href=" http://www.livescience.com/5729-robots-ethical-decisions.html">follow complex moral subroutines</a>. </p<p>Science Rating: Possible.</p>
<p>In the future depicted in the film, police rely on psychics who can see the future to stop crimes before they happen. Although precognition is fantasy as far as we know, director Steven Spielberg enlisted a cadre of futurists to develop a picture of where the future might head, including <a href="http://www.livescience.com/9384-wave-hand-draw-3d.html">gesture-based computer interfaces</a> and <a href="http://www.livescience.com/7180-minority-report-ads-future.html">ads that refer to people by their names</a>, which we see in relatively primitive form nowadays. Moreover, the investment arms of the CIA and Google are both backing a company that monitors the Web in real-time to try to predict the future. So maybe precognition isn't as implausible as it seems.</p><p> Science Rating: Optimistic.</p>
<p>Rings of extraterrestrial origin serve as gateways to adventure, by opening wormholes to distant worlds where the heroes confront aliens posing as Egyptian gods. Although scientists have conjectured that <a href="http://www.livescience.com/2306-teleportation-wormholes-science-jumper.html">wormholes could theoretically exist</a>, these would be spherical in shape like a black hole and would allow two-way travel, unlike the flat disks shown on "Stargate" that only allow one-way travel. The first show to spinoff the movie, "Stargate SG-1," did endeavor to explore some of the potential scientific consequences of the device, such as how a gate open near the edge of a black hole would experience time dilation, where time would essentially pass at a different rate than normal.</p><p> Science Rating: Hard to Imagine.</p>
<p>Aliens tinker with the evolution of the human species and leave behind artifacts that can hurl astronauts through space and transform gas giant planets into stars. Science-fiction legend Arthur C. Clarke was well-versed in science, being the physicist who first developed the notion of communications satellites, and while some elements of his stories might seem fantastic, he also coined the phrase, "Any sufficiently advanced technology is indistinguishable from magic." His <a href="http://www.space.com/7755-arthur-clarkes-2010-reality.html">science regarding many other aspects of the stories</a>, including artificial intelligence, nuclear physics, orbital mechanics, suspended animation, videophony, moon colonization and voice recognition, were plausibly depicted, if now optimistic given common assumptions at his time.</p><p> Science Rating: Optimistic.</p>
<p>In the grim and gritty future depicted by "Blade Runner," humanoid replicants must be hunted down and killed wherever they are found on Earth. These androids are bioengineered — although they are artificial life, if they are as human as they often disturbingly seem, their development may fall well within the realm of technical possibility when compared with attempts so far to create mechanical humanoids. Space travel is apparently commercially available, but seems a distant possibility, much like today. Even the movie's <a href="http://www.livescience.com/12667-flying-cars.html">flying cars</a> now seem possible, given recent advances.</p><p> Science Rating: Possible.</p>
<p>In 1988, a spaceship carrying a quarter-million slaves from the planet Tencton gets stranded in the Mojave Desert. These "Newcomers," who prefer to drink sour milk and eat meat raw, quickly join U.S. society. Although the humanoid aliens of the movie and show were mostly meant to explore questions regarding alienation and acceptance on many levels, their biology proved a major factor in storylines. Newcomers possess three sexes, with females needing to mate with two different kinds of males, a setup similar to that seen in a number of real species of harvester ants. Male Newcomers also incubated young, carrying them in pouches just as kangaroos do and giving birth to them like male seahorses in real life.</p><p> Science Rating: Optimistic.</p>
<p>Explored in greater depth in "Caprica," the spinoff show of the re-imagined "Battlestar Galactica," the Twelve Colonies of Kobol are apparently located on planets within a cluster of four stars, which are connected as a civilization by faster-than-light spaceships. Although a number of these colonies are located on planets, others are based on moons at a planet's <a href="http://www.space.com/6569-search-solar-system-lost-planet.html">Lagrange points</a> instead of more conventional orbits. The civilization is virtually <a href="http://www.livescience.com/3397-robot-madness-preventing-insurrection-machines.html">completely destroyed by the sentient machines</a> known as Cylons that humanity created as soldiers and workers.</p><p> Science Rating: Optimistic.</p>
<p>In the Terminator movies and series, machines and humans from the future constantly try to rewrite history, deploying soldiers backward in time to kill or protect vital historical figures. The villainous <a href="http://www.livescience.com/5424-terminator-creepy.html">Skynet</a>'s main tools in this war are Terminators, most famously consisting of robotic skeletons encased in flesh, although more advanced models are made of shapeshifting metal. The jury is still out as to whether <a href="http://www.livescience.com/1817-time-travel-machine-outlined.html">traveling backward in time</a> is possible, although <a href=" http://www.livescience.com/1339-travel-time-scientists.html">many are skeptical</a>. Still, not only are scientists working on humanoid robots, they are endeavoring to essentially <a href=" http://www.livescience.com/5872-mad-science-growing-meat-animals.html ">grow flesh in vats</a> as well, suggesting Schwarzenegger cyborgs might one day actually exist. Relatively primitive <a href=" http://www.livescience.com/6636-programmable-matter-lead-universal-toolbox.html ">shapeshifting machines</a> are being developed as well.</p><p> Science Rating: Optimistic.</p>
<p>In the original movie "Alien," a team of humans and an android uncover alien eggs, which hatch parasitic "facehuggers" that kill their hosts, spawning a dangerous predator with acid for blood and two sets of jaws. In these aspects, the creature is reminiscent of real animals seen on Earth — for instance, the eggs of <a href="http://www.livescience.com/1-image-day.html/siod_080918.html">parasitoid wasps</a> find their way into victims and go on to hatch and kill their hosts, and moray eels <a href="http://www.livescience.com/1834-eels-doom-prey-alien-jaws.html">actually possess two pairs of jaws</a> Later movies revealed this "xenomorph" had a hive structure with a single fertile queen protected by a caste of warriors, much like real ants and bees.</p><p> However, the movies also suggest the xenomorph could absorb its host's DNA and take on some of its physical attributes, which seems unlikely, as humans should have more in common with a stalk of wheat than an extraterrestrial. In addition, xenomorphs can somehow retain the memories of their hosts in their genetic material, allowing clones made from these molecules to remember the past lives of the hosts — something movie critic Roger Ebert likened to cookie dough remembering what a gingerbread man looked like. </p><p> Science Rating: Hard to Imagine.</p>
