Planets in science fiction
are fictional planets
that appear in various media, especially those of the science fiction
genre, as story-settings or depicted locations.
turned his telescope
to the heavens, the planets of the Solar System
were not recognized as potential locations or worlds. They were visible to observers merely as bright points of light, only distinguishable from stars by their motion.
In the system of Claudius Ptolemy (fl. c. 150), the Alexandrian astronomer whose works were the basis of all European astronomy throughout the Middle Ages and Renaissance, the planets were lights set into a series of transparent spheres turning around the Earth, which was the center of the one and only universe. Dante (1265-1321), in his Paradiso, describes the ascent of his narrator through the spheres of the Moon, the planets from Mercury to Saturn, and thence to the sphere of the fixed stars and the heavens of the angels. Dante implies that the light of the planets is a combination of light imparted by Divine will and the radiance of the blessed souls that inhabit the spheres. These planets are, however, entirely ethereal; they have light but no physical form and no geography.
Ludovico Ariosto, in his epic Orlando Furioso (1513), jestingly sent his hero to a Moon where everything lost on Earth eventually turns up; but it was not until Galileo discovered (1609-1610) that the Moon had surface features, and that the other planets could, at least, be resolved into disks, that the concept that the planets were real physical bodies came to be taken seriously. In 1543, Nicolaus Copernicus had already posited that the planets orbited the Sun as the Earth does; combined, these two concepts led to the thought that the planets might be "worlds" similar to the Earth. Public expression of such concepts could be dangerous, however; Giordano Bruno was martyred in 1600 for, among other things, imagining an infinite number of other worlds, and claiming that "Innumerable suns exist; innumerable Earths revolve about these suns ... Living beings inhabit these worlds" in De l'infinito universo e mondi ("Concerning the Infinite Universe and Worlds", 1584).
At the time, such speculation was of a rather rarefied sort, and was limited to astronomers like Christiaan Huygens who wrote a book, Cosmotheoros (1698) considering the possibility of life on other planets; or to philosophers like Campanella, who wrote in defense of Galileo. The concept of life on distant planets was not, however, much utilized in fiction. The most popular target of 17th century "science fiction" was the Moon ("visited" in fiction by Kepler, Godwin, Cyrano, and Defoe). Oddly, none of these fictions made use of the lunar maps contemporaneously created by Hevelius, Riccioli and others.
It was quite some time before such "extraordinary voyages" went beyond the lunar sphere. Eberhard Kindermann sent an airship to the planets in 1744 in Die Geschwinde Reise auf dem Lufft-schiff nach der obern Welt ("The Airship's Speedy Journey to the Upper World"); while a traveller from the star Sirius passes inward through the Solar System, stopping at various planets in Voltaire's Micromégas (1752); followed by another outward voyage in Marie-Anne de Roumier-Robert's Voyage de Milord Céton dans les Sept Planètes ("Lord Seton's Voyage Among the Seven Planets", 1765). These stories were generally unscientific and tended towards the satirical rather than the purely entertaining; their subject-matter was probably inspired by the popular writings of Fontenelle, notably his Entretiens sur la pluralité des mondes ("Conversations on the Multiplicity of Worlds", 1686).
With the rapid developments in the magnifying and resolving power of telescopes in the course of the 19th century, it finally became possible to distinguish surface features on other planets and even to draw maps of some of them, notably Mars. In 1877, Asaph Hall reported two moons of Mars and Giovanni Schiaparelli found the surface of Mars to be adorned with continents, seas, and canals, and a very suitable habitat for life. From the beginning of the 1880s, fictions – some more, some less scientific – involving travels to and from Mars began to be produced in great quantities, even though the observations of Percival Lowell required reassessment of Mars as a more marginal desert planet. Mars remained a favored destination for fictional travellers down to the early 1960s (see Mars in fiction). Since probes revealed the absence of any indications of intelligent life on Mars, the science fictional Mars has changed to a possible future home for the human race, e.g. through terraforming.
Venus was never quite so popular as Mars, probably because it obdurately refused to display any surface features (it is covered with sulfuric acid clouds only dimly translucent to visible light), making any statement about its nature disturbingly speculative. In 1918, chemist Svante Arrhenius, deciding that Venus' cloud cover was necessarily water, decreed in The Destinies of the Stars that "A very great part of the surface of Venus is no doubt covered with swamps" and compared Venus' humidity to the tropical rain forests of the Congo. Venus thus became, until the early 1960s, a place for science fiction writers to place all manner of unusual life forms, from quasi-dinosaurs to intelligent carnivorous plants, and where hostile interactions with Venusian natives were reminiscent of European colonial projects in Africa and Asia (see Venus in fiction). In fact Venus's surface is hot enough to melt lead, and it is extremely hostile to life.
Various other planets of the Solar System were used as settings for science fiction stories in the first half of the 20th century; but dissatisfaction with the limits imposed by science led many writers early on to forsake the Solar System for fictional planets around distant stars. As increasing knowledge of the Solar System made the prospects of life in the vicinity of Earth marginal at best, the extrasolar planet has become almost the only venue for contemporary science fiction.
In many works of science fiction, planets are only described casually, as points of origin and departure, or as interchangeable backdrops for space battles. This is particularly true of space opera. In other works, the planet takes center stage as the primary scene of events, and particular attention is paid to its environment and any culture that may exist on it. Adventure stories that stick to a single, well-described planet are sometimes called planetary romances; some of these planets are not very realistic and are effectively fantasy worlds.
Planets may be treated in different ways depending both on the interests of the author and the genre he or she is writing in. In some stories, a planet is mainly considered as an object in space: the interest of the fiction depends upon its astronomical characteristics, such as its mass, its geological composition, its atmosphere, how many moons it has and what size they are, how close it is to its sun (or suns) and how hot they are. Such considerations are found prominently though not exclusively in the hard science fiction genre.
In other stories, a planet is considered as a world or setting. Such a planet will be described from the point of view of a person dwelling on it, rather than from the point of view of an outside observer: the fiction may describe its geography, its history, and the social and cultural characteristics of its civilizations. Since authors usually adopt human protagonists, such planets are typically described as very hospitable to human life and, other than in geography, nearly indistinguishable from Earth; Brian Stableford calls such planets "Earth-Clones. Conversely some fictional worlds are never more than marginally habitable, which has a profound effect on societies that developed or moved there. Numerous examples of this are to be found in the Known Space stories of Larry Niven.
While some authors choose to treat a planet in depth, considering it to have a wide diversity of geography, climate, politics and culture, others prefer to characterize their planets by some single global characteristic. Many of these uniform settings have become stereotypes, used in a variety of science fictional works. Such stereotypes include: the planet covered by a single city; the planet whose surface is entirely desert; the planet covered by ocean, with no landmasses; the planet on which it is perpetually winter; the planet that is self-aware; and the planet which has been artificially constructed.
Other planets appear in humorous or comical settings, sometimes spoofing more conventional science fiction. Such planets are often described with no pretense to scientific accuracy; their strange characteristics are primarily intended to amuse.
For the Star Trek universe, a detailed Planetary classification has been devised; it is not actually used by scientists.
For planets from specific fictional milieux, use the following lists and categories, or use Wikipedia's search box on this page:
Film and television
- Andromeda – Andromeda (TV series) planets, List of Andromeda star systems
- Babylon 5 – Babylon 5 planets, Civilizations in Babylon 5
- Battlestar Galactica – Battlestar Galactica planets, List of Battlestar Galactica (re-imagining) locations, Twelve Colonies
- Blake's 7 – List of Blake's 7 planets
- Doctor Who – Doctor Who planets, List of Doctor Who planets
- Firefly – List of Firefly planets and moons
- Lexx – Lexx#The Light Universe and Dark Zone, Lexx planets
- Power Rangers – Power Rangers planets, List of Power Rangers planets
- Star Trek – Star Trek planets, List of Star Trek Planets
- Star Wars – Star Wars planets, List of Star Wars planets, List of Star Wars moons
- Stargate – List of Stargate planets
Contains planets not found in the preceding lists.
- Athena — A planet in Tom Godwin's Space Prison (aka The Survivors) and The Space Barbarians, claimed by the Gern Empire and colonized by Terran slave labor before being liberated by the Ragnarokans.
- Altair IV — From the movie Forbidden Planet, formerly inhabited by the mysteriously extinct race of Krell.
- Amazonia - A planet mentioned but not seen in Fireball XL5. In the episode Prisoner on the Lost Planet, Amazonia is mentioned as being a member of the United Planets Organisation alongside Earth, and had banished its mad queen to an unnamed planet alive with active volcanoes.
- Aurelia and Blue Moon — An attempt at theorising what a habitable planet orbiting a red dwarf star and a habitable gas giant moon could actually be like.
- Azeroth — The main setting of the Warcraft games.
- Bafegox — A planet described in many mayan texts. It is supposed to be the paradise.
- Ballybran — A planet in Anne McCaffrey's Crystal Singer series. Ballybran is a toxic world where the inhabitants must form a symbiotic relationship with a spore in order to survive.
- Belzagor — A planet colonized by Earth, whose natives are the elephant-like nildoror, in Downward to the Earth by Robert Silverberg.
- Big Planet — An enormous but not very dense planet, settled by Earth colonists and divided into a large number of colorful social groupings, in the novels Big Planet and Showboat World by Jack Vance.
- Botany — An Earth-like agricultual world to which prisoners and slaves are transported in the Catteni Series by Anne McCaffrey.
- Bronson Alpha and Bronson Beta — Planets that enter the solar system in Philip Gordon Wylie and Edwin Balmer's novel When Worlds Collide. Bronson Alpha collides with the Earth, destroying it. Bronson Beta is settled by survivors of the catastrophe in the sequel After Worlds Collide.
- Cevena - An ice-planet that is home to an unnamed brain-creature in Fireball XL5, where it hopes to use hypnotic satellites to take control of the universe.
- Chiron — A planet (usually called "Planet") orbiting the star Alpha Centauri in the computer game Sid Meier's Alpha Centauri.
- Chthon — The titular prison planet in Piers Anthony's novel Chthon.
- Conva - A planet that is featured regularly in Fireball XL5. It is introduced in the episode Space Pen as a planetwide prison for wanted criminals, and features prominently in the episode Convict in Space, in which one of the convicts escapes from Conva.
- Cyteen — A planet notable for its cloning research, from C. J. Cherryh's Alliance-Union universe novels.
- Gaia — The first planet of the star Betelgeuse, inhabited by the Syreen people in the Star Control computer game series.
- G889 — A planet 22 light-years from Earth in the television series Earth 2.
- Gor — An inhabited counter-Earth in John Norman's Gor series, marked by slavery and rigid gender roles.
- Gorta — A planet circling Proxima Centauri, home of the hostile alien Furons in the video game Destroy All Humans!.
- Granatoid - Home of the Granatoid robots who appear in The Granatoid Tanks, an episode of Fireball XL5. Granatoid is not seen, but is mentioned as being a completely technocratic society, led by a robot who is voiced by an uncreditted Gerry Anderson (who provided the voice of Robert the Robot on the same show).
- Granvenia - A planet mentioned but not seen in Fireball XL5. It is the destination of fuel tankers that are being diverted to the planet Cevena in the episode Hypnotic Sphere.
- Halvmörk — A twilight planet in Harry Harrison's novel Wheelworld.
- Hedera - A planet rich in plant-life that was visited in the Fireball XL5 episode Plant Man from Space. It is the home of a strain of Ivy called Hedera Helixa, which grows at an alarming rate, and is difficult to cut.
- Helliconia — A planet orbiting a binary star in the trilogy of the same name by Brian Aldiss. On Helliconia, with a 3000-year "Great Year", civilizations rise and fall with the change of seasons.
- Herbos - A jungle-planet seen and referenced briefly in the Fireball XL5 episode Last of the Zanadus
- Hydros — A water-covered planet, whose population lives only on artificial floating islands, in Robert Silverberg's novel The Face of the Waters.
- Hocotate — The home planet of Olimar, the main character in Pikmin and Pikmin 2.
- Ireta — A planet in Anne McCaffrey's Planet Pirates series, inhabited by both people and dinosaurs, and so also called Dinosaur Planet – the name of the novel in which it first appears.
- Ishtar — A planet in orbit around three suns, whose northern hemisphere undergoes catastrophic heating every thousand years as it draws near to one of them. From Poul Anderson's novel Fire Time.
- Iszm — A planet in Jack Vance's novel The Houses of Iszm, a world on which bioengineering of plants is the dominant technology form (as opposed to mechanical engineering on Earth). Houses on Iszm are trees with room-sized pods; all furnishings are integrated as part of the growth.
- Jean — A "colony planet" that is the setting for Mark Stanley's webcomic Freefall.
- Kharak — Homeworld (desert planet), destroyed by an enemy race after space travel is developed
- K-PAX — A utopian planet in the novel and film of the same name, which is quite possibly the delusional invention of a madman who claims to be from the planet.
- Krankor — The planet of the supervillain Phantom in the Japanese television series Planet Prince.
- Kregen — An earthlike planet orbiting Antares, in Kenneth Bulmer's Dray Prescot series.
- Krull — Sword and sorcery-themed world from the movie of the same name.
- Kulthea — Principal planet in the Shadow World role-playing game.
- La Maetelle — A dying planet whose orbit changes drastically once in a millennium; the home of Queen Promethium and her daughters in the manga and anime of Leiji Matsumoto.
- Lagash — A planet in the story Nightfall by Isaac Asimov, in a globular cluster, and in a system with six suns. The orbit of the planet is such that all sides of it are almost always illuminated by at least one sun; only once in every 2,049 years is Lagash oriented in such a way that one of the suns is eclipsed by a dark companion body. Only at such times are the stars visible from Lagash's surface. In the novel developed from the short story, the planet was called Kalgash.
- Lamarckia — A planet in Greg Bear's novel Legacy, whose continent-sized superorganisms mimic Lamarckian evolution.
- Land and Overland — Twin planets revolving about a common center of gravity, sharing a common atmosphere and connected by an hourglass-shaped atmospheric tunnel. The setting for Bob Shaw's The Ragged Astronauts, The Wooden Spaceships and The Fugitive Worlds. Travel between the two planets occurs by hot air balloon.
- Leera — Home of the amphibious Leerans in the Animorphs book series.
- Lithia — A planet peopled by an alien species with a well-developed natural ethics but no form of religion, in James Blish's novel A Case of Conscience.
- Lumen — the Planet of Light in the British puppet TV series Space Patrol.
- LV-426, or Acheron — The planet on which the derelict ship and its deadly cargo are found in the movies Alien and Aliens.
- LV-1201 — Planet in the Aliens versus Predator 2 video game.
- Magneton - A planet inhabited by the invisible Solars that was visited in the Fireball XL5 episode Space Magnet
- Majipoor — A large planet which is the setting for a science fantasy series by Robert Silverberg.
- Medea — Harlan Ellison's worldbuilding project
- Mejare and Tarak — Warring planets in the anime Vandread: Mejare is populated entirely by women, Tarak entirely by men.
- Membrono - A planet that was destroyed in the Supermarionation series Fireball XL5, in the episode The Doomed Planet.
- Merseia — Planet that becomes the center of an interstellar empire in Poul Anderson's Technic History.
- Metaluna — A war-torn planet visited in the '50s B-movie cult classic This Island Earth.
- Midkemia — Planet on which the events of the Riftwar books of Raymond E. Feist take place.
- Minerva — Earthlike planet occupying the orbit of Mars in the alternate universe of Harry Turtledove's A World of Difference.
- Mirana - A perpetually burning planet seen in one episode of Fireball XL5, entitled Hypnotic Sphere
- Miron - The homeworld of Bleep, Blink, and Twink in the British children's series Bleep and Booster
- Mondas - The home planet of the Cybermen from the BBC series Doctor Who.
- Mongo — The planetary setting for the Flash Gordon adventure comic.
- Monotane - A desert planet inhabited by a space monster in Space Monster, an episode of Fireball XL5
- Mor-Tax, Morthrai and Qar'To — Planets named in the television series War of the Worlds. Mor-Tax, a planet orbiting a dying star in the Pleiades, is a paradise planet, the homeworld of the aliens invading Earth. Morthrai, first mentioned in the second season, may be another name for Mor-Tax. Qar'To is another planet in the same system as Mor-Tax, inhabited by a different species.
- Nacre — A planet populated primarily by fungi, including an intelligent variety; from Piers Anthony's novels Omnivore, Orn and OX.
- Nemesis — A planet appearing in the anime Sailor Moon.
- New Earth (Planet Bob) - The Earth-like planet created in the Titan AE animated movie.
- New Earth - A planet with a thin atmosphere and little gravity that was to be colonised by the crew of the spaceship Mayflower-3 in the Fireball XL5 episode Space Immigrants. The spaceship Fireball XL7 was sent out in advance to prepare for the arrival of the Mayflower-3, only to be captured by megalomaniacal aliens.
- New Terra — In the computer game Outpost 2, New Terra is the world chosen by humanity as its last hope for survival, colonized by the last survivors of Earth in starship Conestoga.
- Nidor — A cloudy, oceanic planet in stories by Robert Silverberg and Randall Garrett.
- Nihil — An additional planet of Earth's solar system; due to a flaw in space, the planet is invisible except at close range, although it can see most of the other planets. The inhabitants attempt to conquer Earth during the 30th century. From the novel Beyond the Spectrum by Martin Thomas.
- Pandarve — A living, sentient planet, considered to be a goddess, in the Storm comic book.
- Perdide — A planet that serves for much of the setting of the 1982 French animated science fiction movie Les Maîtres du Temps (Time Masters), by Rene Laloux.
- Pern — A planet pelted by a deadly spore (called Thread), capable of eating anything but rock and metal, for periods of fifty years every two to four centuries in Anne McCaffrey's Dragonriders of Pern novels. The people of Pern live in caves and ride genetically-engineered flying reptiles ("dragons") capable of incinerating the spore in midair.
- Petaybee — A living planet, becoming sentient, in Anne McCaffrey and Elizabeth Ann Scarborough's Petaybee Series.
- Pharagos — A fantasy planet in the Dungeons & Dragons role-playing game.
- Placet — A planet that revolves in a figure-8 orbit around the twin suns Argyle I and Argyle II, and is subject to several different spatio-temporal anomalies in Fredric Brown's Placet is a Crazy Place.
- Planet 46 - The home of the Subterraneans in Fireball XL5. It is a barren planet with an oxygen atmosphere, introduced in the pilot episode Planet 46 and appeared in numerous other episodes.
- Planet 73 - A planet colonised by Earth that was attacked by the Granatoids in the Fireball XL5 episode The Granatoid Tanks
- Platonia - A planet featured in Fireball XL5. In the episode Planet of Platonia, it was revealed to be a world rich in Platinum, and inhabited by silver-skinned aliens who eat 23-course meals. A trade agreement with Earth had created a power-struggle on the planet, which the XL5 crew had been sent to calm.
- Prism — A planet in Alan Dean Foster's Humanx Commonwealth populated by crystal-based lifeforms.
- Prysmos — A planet orbiting three stars in the cartoon Visionaries: Knights of the Magical Light.
- Pyrrus — An inhabitable planet whose ecosystem, consisting of psychic plants and animals, seems to be unremittingly hostile to human life. From Harry Harrison's Deathworld trilogy.
- Ragnarok — A planet in Tom Godwin's Space Prison (aka The Survivors) and The Space Barbarians. Ragnarok's inhabitants suffered from high gravity, temperature extremes, Hell Fever, unfriendly wildlife such as prowlers and unicorns, and a dearth of natural resources.
- Regis III — A planet populated by evolving machines in Stanisław Lem's novel The Invincible.
- Reverie — A planet with extreme social division between the haves and have-nots, in Bruce Sterling's The Artificial Kid.
- Riverworld — The title planet of Philip José Farmer's Riverworld series, where all humans in history are reincarnated along a spiral river.
- Rocheworld — A pair of twin planets that almost touch in the book of that name by Robert Forward.
- Rubanis — A megalopolitan planet plagued by constant traffic congestion, appearing in several volumes of the French comic book series Valérian and Laureline, particularly in The Circles of Power.
- Takis — The home planet of Dr. Tachyon.
- Targ — The planet on which the computer game Mercenary and its sequels take place.
- Thalassa — A watery planet colonized by Earth, and revisited by a ship travelling to the planet Sagan 2 in Arthur C. Clarke's novel The Songs of Distant Earth.
- Thra — The world of The Dark Crystal.
- Thundera — Home planet of the ThunderCats.
- Tiamat — An oceanic planet whose sun orbits a black hole, socially divided into two moieties (Summer and Winter), ruled by a queen with abrupt changes in social conditions every 150 years. From Joan D. Vinge’s The Snow Queen.
- Tirol — The homeworld of the Robotech Masters in the anime Robotech.
- Titan — The setting of the Fighting Fantasy gamebooks; not to be confused with the Saturnian satellite Titan.
- Tormance — A planet orbiting Arcturus in David Lindsay's novel, A Voyage to Arcturus.
- Tralfamadore — A planet populated by the phlegmatic Tralfamadorians in the works of Kurt Vonnegut.
- Troas — An Earthlike planet featured in the stories "Sucker Bait" by Isaac Asimov and "Question and Answer" by Poul Anderson.
- Tschai — The sole planet of Carina 4269, 212 light-years from Earth, slightly larger than Terra and populated by three alien races, one sentient native species and various human races, as described in "Planet of Adventure" by Jack Vance.
- Twinsun — A planet lit by two fixed suns, both fixed relative to it, in the Little Big Adventure computer games. Twinsun has three climates: the poles are hot and desert, the equator is cold and Arctic, and between them lie temperate lands.
- Water-O — The water-covered planet from the cartoon series TigerSharks.
- Wormwood — In the role playing game Rifts, a chaotic planet in another plane. Wormwood is alive, and its inhabitants can draw on its life force.
- Zahir — A hollow planet appearing in the comic book series Valérian and Laureline.
- Zanadu - A planet that features a mysterious temple in the Fireball XL5 episode Last of the Zanadus
- Zavia - An ice-planet where the spaceship Fireball XL27 was attacked in the Fireball XL5 episode, The Day the Earth Froze
- Zeelich — A planet covered by a thick layer of gas clouds above a sea of lava in the computer game Little Big Adventure 2. Vegetation and civilisation occur only on mountains rising above the cloud layer.
- Zolpheid - A planet whose population - the Zolphites - was almost wiped out (only two males surviving) by a lone alien in Fireball XL5, in the episode XL5 to H20. The crew of XL5 rescued the two survivors, who were evacuated to Earth.
- Zyrgon — A planet ruled by the galactic "Law-Enforcers" in novels by Robin Klein, adapted as a television series.
These planets are not so much carefully constructed worlds as they are humorous backgrounds or gag references in various comedy shows and games:
- Arazon - A prison planet featured in the comic novel Bikini Planet by David S. Garnett. It is colliquially known as "Clink".
- Druidia — Home of the Druids, ruled by King Roland and Princess Vespa in the movie Spaceballs.
- Freleng — Zadavia's and Optimatus' homeworld in the animated series Loonatics Unleashed. The name is an homage to animator Friz Freleng.
- Gordon - A planet visited in the British Claymation series Rex the Runt. All the inhabitants of the planet are sapient plant-pots who are all called Gordon, with the exception of one named John. The planet is referenced frequently but is never actually seen.
- Hideaway - An "entertainment planet" appearing in the comic novel Bikini Planet by David S. Garnett, and briefly in the precursor novel Stargonauts.
- Htrae — A version of Earth in which everything is backwards, in the scifi television comedy Red Dwarf.
- Jupiter Two - A planet mentioned by name in Spaceballs. It is mentioned as being close to Druidia, but it is not actually shown on-screen.
- Koozebane — A mysterious planet full of weird aliens, encountered several times in the television puppet comedy The Muppet Show.
- Marklar — A planet that appeared in four episodes of the animated television series South Park, most prominently in Starvin' Marvin in Space, where all nouns are replaced by the word 'Marklar'.
- Melmac — The home planet of the alien Gordon Shumway in the television comedy ALF.
- Ork — The home planet of the humanoid alien Mork in the television situation comedy Mork & Mindy.
- Pop Star — A planet in the Kirby series of video games. It is star-shaped and has a sun and moon that revolves around it.
- Remulak — The home planet of the aliens in the comedy sketches (and movie) The Coneheads.
- Rigel 7 — The home planet of drooling aliens Kang and Kodos on the animated comedy The Simpsons.
- Rimmerworld — A planet populated by millions of clones of Arnold Rimmer who had spent six hundred years alone on this planet, creating clones of himself in a failed attempt to create a girlfriend. From Red Dwarf.
- Shroob planet — The (assumed) homeworld of the alien Shroobs in the video game Mario & Luigi: Partners in Time.
- Skyron — Planet in the Andromeda Galaxy, home of immense blancmanges, in a Monty Python's Flying Circus comedy sketch.
- Spaceball — Planet of the Spaceballs, ruled by President Skroob in the movie Spaceballs, where it has a heavily polluted atmosphere.
- Sushi - A metafictional planet mentioned in Ed, Edd n Eddy, mentioned as the setting for the (fictional) horror film I Was a Teenage Appetiser from Planet Sushi: The Second Coming.
- Thargoidia - The homeworld of the Thargoids in the Captain Kremmen series by Kenny Everett. The city of Gortadia is the planetary capital city.
- Thribb - A planet seen in an episode of Rex the Runt. The planet itself is merely an asteroid with a lecture hall at it's north pole, and the inhabitants all resemble the Easter Island Statues.
- Vega - In the film Spaceballs, the spaceship Eagle-5 crash-lands on the desert-moon of Vega after running out of fuel.
- X — Planet X was the source of Alludium Phosdex, the shaving cream atom, in the animated short comedy film Duck Dodgers in the 24 1/2th Century.
- Xenon — The home planet of Roger Wilco, janitor, in the humorous computer game series Space Quest.
- Yugopotamia — A comic "opposite" planet mentioned in the animated comedy The Fairly Oddparents.
These planets are identical or nearly identical to Earth physically, but have a history that differs to some degree from that of our Earth.
In addition, some writers, scientists and artists have speculated about artificial worlds or planet-equivalents; these planets include:
Some invented planets have physically impossible shapes, and may be regarded as fantasy worlds:
Several planets of the solar system have, at various times, been the basis for fictional worlds with characteristics more or less distinct from those of the actual planet, as presently understood; an early example is Edgar Rice Burroughs' Barsoom, a heroic fantasy version of Mars. For more examples, see the links to the various planets at Solar System in fiction.