Earth in science fiction

Earth is often depicted as a major power-broker in the community due to anthropocentrism. Perhaps the most notable example of this is Star Trek (where Earth is the capital of the United Federation of Planets). It can also be depicted as the head of an empire as in Poul Anderson's Dominic Flandry series where "The barbarians in the long ships waited at the edge of the Galaxy for the ancient Terran Empire to fall … The brilliant Starship Commander Flandry fought to save the empire even as he scorned it" (from the preface to The Rebel Worlds). Marion Zimmer Bradley's Darkover series, too, has a brooding Terran Empire maintaining a colonial enclave on the planet Darkover where the plot takes place, and on countless others. Haegemonia: Legions of Iron also features an empire controlled from Earth with other major planets, such as Eden IV. It is a common theme across British science fiction to have Earth near the core, or center of the fictional universe, common examples could be the works of Peter F. Hamilton where earth is the main terminus of the wormhole and the capital of the inner worlds (in later works he turns the idea that people seek an inner migration (as opposed to an external expansion) to frontier type worlds). In the BBC science fiction show Doctor Who, many episodes set in the future depict Earth as being the head of an empire that stretches across many galaxies. In the Warhammer 40,000 franchise, Earth is referred to as "Holy Terra" and is the capital of the Imperium of Man

While reasons vary, in most stories, it is because extraterrestrials are looking for a new world to colonize or otherwise dominate. The aliens are often used to portray nearly all-powerful beings, placing the strongest forces on Earth at the receiving end of attacks that they can barely understand. This theme is one of the earliest in science fiction, demonstrated by H. G. Wells in The War of the Worlds and Doctor Who, where the invasions in the 1960s, 70s and the 80s are small scale, and the invasions from the 1990s and later are more-large scale, in works such as Independence Day. In such scenarios, the author often uses deus ex machina to allow the invasion to be repulsed. In others, like Footfall and Worldwar, the author depicts aliens only slightly more advanced than the inhabitants of Earth, and are fought to a stand-still or defeated in battle. The opposite has also been depicted, with Earth becoming a refuge to aliens as seen in the Men in Black series of movies, and Alien Nation series.

The memory of Earth, and its location may be lost to the sands of time or shrouded in myth as mankind abandons the Earth. Isaac Asimov's Foundation and Empire series depict a common theme of a destroyed Earth. In other works, such as Battlestar Galactica, it is largely forgotten except by the religious. In the numerous books of the Dumarest saga by E.C. Tubb, the adventurer protagonist was born on a "galactic backwater" Earth and at a young age had stowed away on a rare spaceship touching down on the planet; having seen more than enough of the galaxy he wants to go back, but no one else had ever heard of the planet. The first Terran inhabitants of the Koprulu Sector are Earth-born criminals in sleeper ships in StarCraft. The expansion also mentions about Earth: upon hearing of the United Earth Directorate's forces' arrival, Zeratul remarks "Raynor [a Terran captain] spoke to me of the distant Terran homeworld of Earth." This implies that the Terrans still know about Earth but its location is lost (StarCraft manual mentions that the sleeper ships have become lost in hyperspace when an error erased the intended destination's coordinates, as well as those of Earth's, resulting in the ships going at full speed for several decades until the engines broke down). Also, the Terran Confederacy uses the same flag as the Confederacy in the American Civil War. Also, in the Zodiac series by Romina Russell, it states that "history tells us the original human colonizers came from a distant and long-gone planet called Earth, and they traveled through a portal in Helios to get here—but the portal is just another myth."[1]

Earth could have been completely destroyed or rendered uninhabitable, but its location (or at least its former location) is well known. This last scenario is also popular, and was featured in the movie Titan A.E., as well as in The Hitchhiker's Guide to the Galaxy. There is an example of a devastated uninhabitable Earth in Roger Zelazny's 1973 novel To Die in Italbar.

Some works, such as Star Wars series and many fantasy works, never mention the Earth at all (although a proposed novel, Robert J. Sawyer's Alien Exodus, would have linked Earth to the Star Wars universe).[2][3] This allows the author to operate in a realm unfamiliar and otherworldly to the reader or to explore contentious issues and historical themes in an otherwise entirely alien environment, giving the work a radically different perspective. In the Homeworld games for example, Earth's existence is unknown – and indeed entirely immaterial – as the games take place in a different galaxy altogether (specifically the Whirlpool Galaxy). However, judging by the appearance of members of the Kushan/Hiigaran people, most notably Karan S'jet, Hiigaran biology is at least outwardly similar, if not identical, to human biology.

The overarching plot in both the original and re-imagined Battlestar Galactica is the quest to find Earth, which is thought to be the location of the lost thirteenth colony of Kobol. Colonial history dictates that Kobol is the homeworld of all humanity, and that the Thirteen Tribes of Kobol fled that world thousands of years earlier, with twelve tribes founding the Twelve Colonies and the thirteenth heading to Earth. Both shows are similar in that the location of Earth is initially unknown, but clues to its location are gradually discovered by the refugee fleet from the Twelve Colonies. In both series, the exodus of the Thirteen Tribes took place so far in the past that most modern Colonials have come to assume that the stories of Earth are simply religious myths.

In the original series, several clues indicate that the existence of Earth is real. On the prison planet of Proteus, Starbuck encounters drawings of star systems on the wall of a cell once occupied by a mysterious prisoner. The star charts turn out to be that of the Solar System. Additionally, when the Galactica later reaches a planet called Terra, it is inhabited by humans who use Earth units of measurement (hours, minutes, etc.) rather than Colonial units of measurement, suggesting that it was settled by members of the lost Thirteenth Tribe thousands of years earlier on their way to Earth.

In Galactica 1980, a continuation of the original series, the fleet did eventually discover Earth as it was in 1980.

In the Season Three finale of the re-imagined series, Kara Thrace returns to Galactica after her apparent death, claiming to have been to Earth, and intending to lead the fleet there. The camera then pans out from the fleet to view the Milky Way galaxy, and then zooms back in to show Earth, confirming the existence of the planet. In the Season Four mid-season finale episode "Revelations," the fleet finally reaches Earth, only to discover that it is a lifeless, radioactive wasteland.

In "Sometimes a Great Notion", it is revealed that the Thirteenth Tribe consisted of humanoid and mechanical Cylons of a type previously unknown. It is also revealed that the final five Cylons had previously lived on Earth 2,000 years in the past, when a nuclear war devastated the planet.

In the final episode, a twist ending shows Galactica reaching our Earth, 150,000 years ago. The Colonials and the Cylons they've made peace with decide to call their new world "Earth" due to the hope associated with the name of the now devastated planet the Thirteenth Tribe once inhabited. They then abandon their technology, and live amongst the new Earth's native Hominini. 150,000 years later, in the present day, the remains of Mitochondrial Eve – a Colonial human/Cylon hybrid (named Hera Agathon), whose birth and destiny had been a major plot element of the series – are discovered.

In most variations on the Buck Rogers mythos (comic strip, TV series, feature film), Earth of the 25th century (where the action takes place) is recovering from various atomic wars, usually variations on World War III. In the original comic, Mongols have taken over the Earth; in the TV series, the Draconian Empire fills this role (although the Draconians are obviously based on Mongols). Most of Earth's cities lie in ruins, although rebuilding is in progress (Earth's capital is New Chicago; other cities include New Paris, New London etc.). The second season of the TV series revealed that much of Earth's population fled the planet in the wake of the atomic war and founded colonies in deep space; the Earth ship Searcher is dispatched to investigate.

In Joss Whedon's Buffyverse, established by Buffy the Vampire Slayer and Angel, Earth is one of several dimensions; the term "Earth" is used both to refer to the specific planet and to the dimension the planet exists in as a whole. Born from the Seed of Wonder, the source of all magic, Earth originated as a world of Demons, and was ruled over by the Old Ones during a time known as the Primordium Age. Eventually, however, the human race rose up and fought back against the Old Ones, banishing them to other dimensions.

In Jerry Pournelle's CoDominium series (now largely alternate history) the Earth comes under the control of the CoDominium, an alliance between the United States and Soviet Union, in the year 1990. The CoDominium imposes its control over all other nations of the Earth, halting scientific development and warfare. The CoDominium is ruled by a Grand Senate located on the Moon, and eventually constructs interstellar colonies for the joint goal of economic gain and a means of exiling troublesome elements of society. Eventually in 2103, the CoDominium dissolves, with the US and USSR engaging in the nuclear "Great Patriotic Wars" which destroy almost all of Earth (it is mentioned that Jamaica and the Tyrolean Alps are untouched).

The CD Space Navy escapes to the planet Sparta, which eventually becomes the nucleus of the "Empire of Man". During the Empire's Formation Wars the Earth is once more hit hard, but is eventually incorporated into the Imperium as the "honorary capital." When the Empire dissolves in the Secession Wars in the 27th century, Earth is once more subjected to nuclear attacks, but by the early 31st century has been reclaimed by the Second Empire. By that time, the Earth city of "New Annapolis" is a training center for the Imperial Space Navy. To inhabitants of planets newly contacted, such as Prince Samual's World in "King David's Spaceship", the condition of the still largely desolate Earth is presented as an object lesson for the prohibitive price of war and a justification for Empire's claim to universal rule.

In Akira Toriyama's Dragon Ball series, Earth is the primary setting and one of many planets in the North Galaxy. The planet is inhabited by humans, anthropomorphic animals, and demons, among others. Dragon Ball's Earth features heavy science fiction themes, such as humanoid robots and flying cars, as well as heavy magical influence.

In Frank Herbert's Dune series of novels, Earth is referred to as Old Earth / Old Terra by the time of the original novel Dune (at least 21,500 years in the future). The Sun is called Al-Lat, and humanity had populated many planets (among them Caladan, Giedi Prime and Salusa Secundus). In the time of Paul Atreides, the Earth is an uninhabited and largely forgotten land, shrouded in legend. In Dune Messiah, Paul refers to Hitler and Genghis Khan, in comparing the destructiveness of his Jihad to their wars. It is a wilderness and recovering an ecosystem of its own as humans have abandoned it. The artifacts of Homo sapiens have for the most part crumbled back into the planet, though a more than casual observer can find many traces of the old civilizations.

Paul's son, the God Emperor Leto II, refers to the Earth many times in his journals. The God Emperor seemed particularly fond of the ancestors he had from the Western sections of Eurasia. He makes references to Israel, Urartu, (also called Armenia), Edom, Damascus, Media, Babylon, Arpad, Umlias, the plains of Central Asia, and the Greeks; the family name refers to their descent from Atreus. He seems to have had ancestors among the Turks or the Mongols as he says that one of his memories involves a horse plain with felt yurts. Leto also has the memories of a famous politician from the United States whose name was Jacob Broom. In the book Children of Dune, Leto II mentions an ancestor named Agamemnon, and makes reference to Geoffrey Chaucer and the Canterbury Tales.

In Heretics of Dune, it is noted that the Bene Gesserit Mother Superior Taraza has the preserved Vincent van Gogh painting Cottages at Cordeville hanging in her room.

In the Legends of Dune series by Brian Herbert and Kevin J. Anderson, set in the Dune universe, it is revealed that at the beginning of mankind's war with the Machines, called the Butlerian Jihad, Earth had been devastated by humans themselves using atomics in an attack on the Machines. In the Prelude to Dune prequel series, also by Herbert and Anderson, it is mentioned that certain Monet and Gauguin paintings are owned by House Vernius, and hang in the Grand Palais at Ix.

In the Joss Whedon series Firefly, Earth is long since abandoned. It is referred to with awe as "Earth-that-Was", having been abandoned centuries ago due to overpopulation and depletion of the planet's natural resources. After fleeing the planet, the remnants of humanity traveled in generation ships for decades (many humans lived their entire lives within a spaceship's walls) until finding a new star system. Collection of Earth-that-Was artifacts is a hobby for the rich, and ancient Earth artifacts are known to be very valuable.

It is unknown whether Earth has actually been destroyed, or if the planet still physically exists; in the feature film Serenity, ancient starships are shown leaving a sickly brown Earth with gray oceans, but the fate of the planet is never fully revealed. A puppet show in the episode "Heart of Gold" implies that Earth has in fact been obliterated, but this was never actually confirmed on screen.

In much of Isaac Asimov's fiction, the future Earth is an underprivileged planet — impoverished, overcrowded and disease-ridden — which is regarded with disdain by the arrogant Spacers of the "Outer Planets" (at this stage, there are about fifty of them).

In the Robot series, the inhabitants of these planets are still aware that their ancestors came from Earth, but this does not make them fond of the place. Rather, they develop a racist theory by which "the best strains" had left Earth to colonize the other planets and left "the inferior strains" behind. However, they have no choice but to ask the help of the protagonist, a detective from the despised Earth, to solve murder mysteries which baffle their own police. Afterwards, Earth embarks on a major new campaign of space colonization, with the hope that the new colonists will prove more faithful to the Mother Planet than the earlier ones. However, in the end of the series, the Earth is doomed to a slow radioactive process that will leave the planet uninhabitable, causing a more rapid expansion of colonization from Earth.

In the Galactic Empire series, taking place thousands of years later (originally conceived as completely separate but made by Asimov in his later career into the direct sequel of the Robot Period), Earth and settlements from it are still clearly remembered in The Stars, Like Dust. By the time of The Currents of Space, Earth is ruled by Trantor, not yet a Galactic Empire. Its status as the original homeworld of humanity is now disputed.

In Pebble in the Sky, we see Earth in the early days of the Empire of Trantor. Earth has a largely radioactive crust with only patches of habitable land in between, and its people have to undergo compulsory euthanasia at the age of 60. It is a backwater province, and among inhabitants of other planets there is a prevalent prejudice known as "Anti-Terrestrialism", (obviously modeled on antisemitism), with the main negative stereotype having to do with the radiation-induced diseases prevalent on Earth.

By this time, Earth people still believe themselves to be the original home of Humanity, but hardly anyone else shares this belief. Fanatical priests, based in a mysterious Temple erected on the ruins of Washington, D.C., cultivate the mystique of Earth's ancient glories and conceive a plot to spread a Terrestrial disease throughout the Galaxy and in this way take over the Empire (and incidentally, act out the stereotype). The plot is foiled by a middle-aged tailor from the Twentieth Century, who possess powerful psychic abilities as a result of experiments performed upon him when he arrived in the future. Schwartz, the tailor, is often described as being Jewish, though this is never stated within the novel.

By the time of the Galactic Empire's decline, Earth is vaguely remembered as 'Sol' in Foundation, and only one candidate for being the Original World. In Foundation and Earth, records of Earth are missing, so two citizens of the mature Foundation go looking for it, and eventually find that it is desolated by nuclear radiation. The only sentient being remaining in the Solar system is robot Daneel Olivaw, who resides in a small station on the moon, overseeing the progress of a humanity now spread throughout the galaxy.

In Ursula K. Le Guin's Hainish Cycle our Earth is referred to as Terra. Like all human worlds of the Hainish Cycle, Terra was populated by the humans of Hain in Earth's prehistory, but forgot our common ancestry after millennia of no contact from extraterrestrial humans after the collapse of the first Hainish interplanetary civilization.

The second period of contact with the interstellar Hainish community, now organized as "The League Of All Worlds" is described in The Word for World Is Forest, The Dispossessed, and Rocannon's World. In The Dispossessed, Terra's population is said to have fallen from 9 billion to only half a billion people due to a collapse of the Terran ecology, and that life has only survived there because of strict rationing of resources and help from the Hainish. In The Word for World Is Forest, the people from Terra appear as reckless exploiters of other planets. Some time later, City of Illusions provides a detailed description of Terra in the depths of a second era of isolation, called "The Age Of The Enemy".

The post-apocalyptic Earth seen in City of Illusions shows signs of an advanced, abandoned civilization under a rewilded landscape. A small number of humans live in tiny, isolated settlements where they retain some technologies from the past but are completely cut off from any communication with neighboring regions or with other worlds. There is only one city with high technology and energy-intensive construction, and it is controlled by the alien conquerors of the League. The events of City of Illusions lead to the third period of Terran contact with other worlds, this time as the Ekumen, during which The Left Hand of Darkness takes place.

In the short story "Dancing To Ganam," which takes place in the far future of the Hainish universe, it is said that an extreme religious movement called the Unists developed on Terra and engaged in mass slaughter of non-believers and then of rival Unists sects. It is described as "the worst resurgence of theocratic violence since the Time of Pollution". It unclear if this time of pollution refers to the ecological collapse described in The Dispossessed, the collapse seen in City Of Illusions, or is another unexplored dark period on Terra. In any case, the inclusion of this story is meant to show that even after so many millennia in the League and the Ekumen, Terra is still in many ways culturally primitive and prone to violent self-destruction.

Various individuals from Terra play a part in other stories. In The Telling, Terra's incorporation into the Ekumen is briefly explained. Also, the main character in The Left Hand of Darkness is from Terra.

In The Hitchhiker's Guide to the Galaxy series by Douglas Adams, the Earth is destroyed by a Vogon Constructor Fleet to make room for a hyperspace bypass. One of two surviving Earthmen, Arthur Dent, is affronted and dismayed to find that his planet's entry in the Guide consists of one word: "Harmless". Ford Prefect, a researcher for the Guide attempts (and fails) to placate him by informing him that he has written a more extensive article for the next edition, although the result of merciless editing of his original draft has reduced his version considerably, now reading "Mostly harmless". Dent also learns that the Earth was originally constructed by the inhabitants of the planet Magrathea, as a giant supercomputer built to find the Question to the Ultimate Answer of Life, The Universe and Everything. The computer was so large that it was often mistaken for a planet, and that it was destroyed five minutes before the program was due to complete (after ten million years of running). It also mentions that humans are descended from the passengers of an ark full of unwanted middlemen (hairdressers, telephone sanitizers, advertising executives and the like), tricked into leaving their own planet behind by spurious tales of impending destruction invented by the rest of the planet's civilization (it is mentioned that the population was then wiped out by a disease contracted from a dirty telephone). The Earth was located in Galactic sector ZZ9 Plural Z Alpha. An alternate version of Earth is the planet NowWhat, which occupies the same space as Earth, but not the same probability. In the 2005 film adaptation, a new Earth replaces the old one, and everything is restored to the moments leading up to its destruction, except for one thing: Arthur Dent is not part of the planet anymore, at his own request.

In the series Red Dwarf, Earth is seen mainly as the goal of the crew's trip; Dave Lister is personally obsessed with revisiting it as his home world, especially since he is the only character to be from there as Arnold Rimmer was born on Io. The novel Infinity Welcomes Careful Drivers mentions the Earth, despite Lister's regard for it, as suffering from massive littering and environmental damage; with a giant toupee being installed to in order to cover up ozone depletion. The novel Better Than Life, however, mentions Earth being voted out of inhabitability to be the solar system's chosen planet of refuse known as Garbage World. A methane build up "farts" the planet out of the system and sends it out into deep space where it becomes an ice planet; later moved and thawed by the actions of the crew of Red Dwarf. The Earth is inhabited by giant cockroaches and the descendants of GELFs sent there as punishment for their rebellion and bred into the polymorph. Lister spends half a lifetime trapped there attempting to correct his species past actions before Red Dwarf can rescue him due to black hole time dilation. In Last Human a parallel Earth is doomed by the initiatives of Earth President John Milhous Nixon and humanity breeds GELFs and simulants to terraform a new home across the multi-dimensional omni-zone.

In the Stargate television series, Earth (designation: P2X-3YZ) is described as one of countless inhabited worlds, and is revealed to be the original home world of humans all over the galaxy. In ancient history many groups of humans were kidnapped and enslaved by powerful alien races, primarily the Goa'uld. Others remained to form present day Earth societies, which interact covertly with other extraterrestrial races and civilizations, many of them human. Earth first became important in the scene after the Alterans occupied it as their new capital (its name was Terra at that point). When they were forced to relocate to Lantea in the Pegasus galaxy (several million years ago), they "seeded" the planet with a less advanced form of themselves. Eventually, the Goa'uld found the planet and determined that the human body is the ultimate host body for their parasitic race. Many humans were kidnapped through the Stargate the Supreme System Lord Ra brought to Earth (Earth already had its own Stargate in Antarctica but it was inoperable) but the leftover population wasn't touched; they eventually rebelled and drove the Goa'uld off the planet in 3000 BC. About 8000 BC, the Lantean remnants returned to the planet but the primitive civilization extinguished their last hope of rebuilding their once great civilization due to the presence of the Goa'uld; as such, the Ancients slowly died out or Ascended since their numbers were too small to survive, even by crossbreeding with regular humans.

With Earth largely left alone for millennia, its human population continued to advance until the rediscovery of the Stargate in 1928 and its subsequent reactivation in 1994 (since its DHD activation device was missing, they had been unable to determine its purpose until they were able to create a computer interface). Unlike an enormous majority of planets, the Stargate on Earth was kept secret from the general populace to prevent widespread panic because "we are not alone".

Humans who are from Earth are referred to as the Tau'ri by most other life forms in the galaxy, including the Goa'uld. Earth is a relatively important player on account of the radical change it unwittingly brought about when troops under the command of Colonel Jack O'Neill killed Goa'uld Supreme System Lord Ra and started a guerrilla war against the Goa'uld. However, its importance pales in comparison to the power of the System Lords or the Free Jaffa Nation, even though after the extinction of the Asgard and the defeat of the Ori, the Tau'ri became the dominant race of known space — although they were initially at a huge technological disadvantage, they later managed to reverse-engineer Goa'uld technology to the point where they started building their own ships, though much of it was rendered obsolete when the Asgard granted a significant amount of non-weapon technology. The Tau'ri also created remarkable technological feats, such as fighters equipped with hyperdrives powered by an unstable isotope. Their power increased further when they discovered that, due to crossbreeding with Ancients before their extinction, some Earth-born humans actually possessed a unique gene required to operate some of the more advanced Ancient technology. The peak of their power occurred when the Asgard donated their entire technological knowledge to Earth prior to their extinction. With this and some Ancient technology, the Tau'ri actually surpassed their precursors and defeated the Ori.

The main interaction between Earth and the rest of the universe is via three organizations:

• The International Oversight Advisory (IOA) coordinates funds and control between the nations of the Earth Stargate; the Atlantis Expedition was sent to the Pegasus Galaxy under its authority. The key players are the Big Five permanent members of the United Nations Security Council: the United Kingdom, the United States, France, the People's Republic of China, and the Russian Federation; also important are Canada, on account of its special relationship with the United States and the services of Dr. Rodney McKay, and other nations, such as Japan, Australia, and Germany, which have also been involved; Germany in particular has sent security personnel to Atlantis.
• Stargate Command, under the control of the IOA and operated by the United States Air Force, conducts off-world missions of diplomacy, tactical strikes, research and exploration. Control of the Stargate is a constant bone of contention with the Chinese, who take every opportunity to express their displeasure at the situation at IOA meetings where the future of Stargate Command is an issue (even though their off-world allies are satisfied with the current situation). Nevertheless, the SGC remains the primary interface between the humans of Earth and the outside world, including the galactic human diaspora.
• The Atlantis Expedition is based in the still sea- and space-worthy city-ship of the Ancients in the Pegasus Galaxy. An international team, with personnel from at least 23 countries, interacts with the other humans of the Pegasus Galaxy (seeded by the Ancients, not taken by the Goa'uld) and the dangerous Wraith. They rely on a mixture of Ancient and Earth technology and were originally based on Lantea until they were forced to relocate to M35-117. The expedition is currently suspended as Atlantis remains on Earth until repairs are completed after its most recent clash with the Wraith.

In the Star Trek universe, the unified human state based on Earth, was one of the founding members of the United Federation of Planets. Several major federal organizations are headquartered on Earth, such as the Federation Council which meets in Paris. The Federation President also keeps offices in Paris, and Starfleet Headquarters is located in San Francisco. Major events on Earth included first contact with the Vulcans (Star Trek: First Contact), barely averted attacks by the Borg (in "The Best of Both Worlds" and Star Trek: First Contact), Founder infiltration ("Homefront"), A successful attack by the Breen during the Dominion War, and numerous attempted coups. Like most other major Federation worlds, Earth is a near-utopia where poverty and war have been eradicated and environmental damage has been reversed. Earth was also the planet of origin for at least one other sentient species, the Voth, according to the Star Trek: Voyager episode "Distant Origin". Descendants of the hadrosauridæ, they are theorized to have fled Earth for the Delta Quadrant after an extinction event.

In the Star Trek: Enterprise episode "The Forge", we learn that the name of the planet's actual government is named United Earth. Much of its early history is unknown, although recent Trek novels have revealed that Earth's governments founded United Earth by signing the historic Traite d'Unification in 2123. The episodes "Demons" and "Terra Prime" imply that United Earth is a parliamentary system of government: we meet various government officials who are referred to as Ministers (such as Minister Nathan Samuels, played by Harry Groener). United Earth's leader is most likely a Prime Minister – possibly, but not necessarily, Samuels himself. In the novels, Earth's governmental structure is further developed. Earth is a parliamentary republic, with a separate head of state (the President) and head of government (the Prime Minister).

In the Mirror Universe, Earth is the capital of the despotic Terran Empire which rules over large portions of the Alpha and Beta Quadrants and is generally seen as the most powerful interstellar empire. Star Trek: Deep Space Nine revealed that the Empire had collapsed and fallen to a Klingon–Cardassian Alliance. Star Trek novels reveal that Earth was later liberated thanks to the efforts of anti-Alliance rebels and Memory Omega.

Earth is the "lost" homeland of the terrans of the Koprulu Sector, often referred to as "Old Earth". Earth history is well known to us until the 21st century. However, by the time the 23rd century was reached, genetic engineering and cybernetics were in common use, and Earth's population had reached 23 billion. Consequently, a resource and overpopulation crisis was developing.

Earth's corporate factions who supported the capitalization of genetic engineering and cybernetics were opposed by those who saw this as a degeneration of the human race. These groups included humanist factions as well as religious conservatives who resorted to terrorism in these turbulent times. The conflict was resolved by the creation of the United Powers League, which generally supported the humanist philosophy and controlled all nations except for a few volatile Latin American states. The UPL banned many religions and made English the worldwide language.

The UPL proceeded to arrest and kill many people who opposed its "divinity of mankind" philosophy (which included "purity" from cybernetics, mutations, and so forth). It was during this time that Doran Routhe set up the colonization of the Koprulu Sector. Contact between the colonists and Earth was seemingly lost, and the Koprulu Sector terrans could not have found their way back to Earth.

With the discovery of the protoss and zerg, the United Powers League reformed to become the United Earth Directorate and launched an invasion of the Koprulu Sector, ostensibly in an effort to protect itself from the distant aliens. The invasion was repelled by a tenuous alliance of the Sector's powers.

In the universe of the Babylon 5 television series, Earth was located in a relatively uncontested and non-valuable portion of the Galaxy. As a result, the people of Earth were allowed to develop with relatively little outside interference or threat of invasion from alien races. Unified under the worldwide government of the Earth Alliance, first contact with the Centauri was made in the mid-22nd century, which led to trade with a number of different species.

Earth remained a relatively minor power until the 2230s, when it intervened on behalf of a number of other races (which later became the League of Non-Aligned Worlds) during the Dilgar invasion. Following the Dilgar War, Earth began to expand its influence and was seen as a rising power in the galaxy. A disastrous first contact with the Minbari in the 2240s precipitated the Earth–Minbari War, in which Earth was nearly conquered: the military (EarthForce) was devastated and the planet's population was nearly annihilated. However, the Minbari mysteriously surrendered just prior to the final invasion of Earth.

Following the war, Earth's major contribution on the galactic stage was the creation of the Babylon Stations, that are neutral trading posts and diplomatic havens. Earth turned inward and suffered from xenophobic tendencies in the late 2250s, early 2260s under the despotic regime of President Morgan Clark, until a military and civilian civil war, started by General William Hague and later concluded by Captain John Sheridan, overthrew the Clark regime and helped establish Earth as one of the major players in the Interstellar Alliance.

In the Robotech canon, based on Macross, Earth is the homeworld of humanity and notable as one of the few places that "The flower of life" (the source of the powerful energy source Protoculture) can grow. In 1999 during a global war the (future) SDF-1 an alien warship crashed to Earth on Macross island. Discovering they were not alone in the universe (and in secret the fact that the SDF-1 was a warship for a giant sized alien race) the human race united and rebuilt the ship as well as using the technology to advance their own and to create a small defence fleet for earth.

Ten years later the ship was ready but as preparation for launch on a mission of exploration continued Zentradi warships arrived in orbit to search for the ship. Though humanity tried peaceful contact a booby trap in the SDF-1 fired the huge main gun at the Zentradi committing Earth to a devastating interstellar war. To lure the Zentradi away from Earth the SDF-1 attempted a space fold FTL jump. This went wrong transporting not only the SDF-1 but part of Macross Island, 70,000 civilians and two navy warships to an area near Pluto. Pressure held in sub-surface shelters long enough to evacuate the civilians while the ships were grafted on to the SDF-1 as flight decks. However the jump also caused the FTL drive to vanish (for unknown reasons) as such the SDF-1 had to return home under normal thrust fighting Zentradi all the way and unable to talk to earth due to jamming.

During the conflict many Zentradi became fascinated by Earth culture and over a million ships eventually defected. The ship finally returned to Earth but was driven back into space to draw off the Zentradi again. However the Zentradi bought over four million ships to Earth and bombarded the planet. The SDF-1 took out most ships with an overload of its shield system but in the process the ship was left incapable of flight and most of the Earth's population was killed. Over the next two years the survivors tried to rebuild and at last the Earth began to green again.

Twenty years later the Earth had recovered during the war with the Robotech masters, but even after Earth's victory the planet was then attacked and occupied by another set of aliens The Invid in 2031. The Invid collected what they could of the Protoculture on Earth but seem to have left the population (now millions once more) largely alone.

In 2042 the Robotech Mars expedition returned from deep space but was wiped out by the Invid during the battle to liberate the planet. The survivors were forced down to Earth where they hooked up with the local resistance groups.

Two years later a massive fleet arrived with more advanced technology given to them by the alien Hydenites. The Invid quickly left Earth rather than risk Earth's destruction by deadly weapons the Neutron_S missiles which were far more dangerous than man believed. As Humanity celebrated however the Hydenites were revealed as the Children of Shadow who had destroyed the Invid homeworld eons before. They launched a sneak attack on the human space station liberty. Another war then began.

In the various continuities of the Sonic the Hedgehog franchise, Earth is mentioned in one way or another:

• The video game series has Sonic living on Earth, specifically a United States-like fictional country known as the United Federation. It is stated in Sonic Unleashed that the planet has been in an endless cycle of destruction and resurrection since time immemorial: a monster known as Dark Gaia hibernates within the Earth's core, absorbing power from the negative energies and emotions of humanity, and destroys the planet when it emerges, and its counterpart, Light Gaia (a.k.a. "Chip"), defeats it and restores the Earth. In the game's plot, Doctor Eggman, hoping to use Dark Gaia's power to build his empire, breaks the planet open himself and awakens both Light and Dark Gaia ahead of schedule; as a result, Dark Gaia's body splits apart, and Light Gaia develops severe amnesia.
• The comic book by Archie Comics reveals that the planet of Mobius is actually the Earth of a distant future; an alien race known as the Xorda launched several bombs meant to exterminate humanity, but instead ended up mutating the various wildlife, giving them humanoid forms, human cognition, and (in many cases) superhuman abilities.
• Fleetway's Sonic the Comic shows Earth existing as a separate planet from Mobius; the two planets are effectively "twins", both having near-identical ecosystems.
• In the Sonic the Hedgehog OVA, the planet Freedom (specifically the Land of Darkness) is heavily implied to be a post-apocalyptic Earth. Early on in the film, Sonic and Tails are seen traveling through what appears to be the ruins of New York City.
• In the anime series Sonic X, Sonic, his friends, and Eggman hail from an alternate version of Earth; Mobius and Earth were once one planet, but a cataclysmic event split the planet into two and sent what would become Mobius into another dimension. The flow of time is different on both planets; one month in Mobuis equals an entire year on Earth.

• According to various sources, including The Adventures of Super Mario Bros. 3, the Mushroom Kingdom and its surrounding areas and locations are part of the "Mushroom World," a parallel version of the Earth, or "Real World." One can travel back and forth between the two dimensions through warp pipes. This is no longer brought up since Yoshi's Island, where the Mario Bros. are now said to have been born and have always lived in the Mushroom Kingdom, hence making the former version of Earth the actual (albeit fictional) Earth in this franchise.
• In the 1993 live-action film, it is stated that the Cretaceous–Paleogene extinction event actually split Earth into two and sent them into different dimensions. The surviving dinosaurs were sent to the alternate dimension, and that world's version of the human race eventually evolved from those dinosaurs rather than mammals. Aside from Dinohattan, a run-down parallel version of New York City, the entirety of the alternate Earth is a desert wasteland.

At least a billion years ago in the Uplift Universe by David Brin, there was a semi-mythical species known as the Progenitors that started the Uplift cycle—adopting a pre-sentient race and over a period of a hundred thousand years of selective breeding and genetic engineering, raising them to full sentience. As a result, most sentient species in the universe are members of various clans and factions, often quite powerful, with varying beliefs.

Earth was overlooked and humans evolved, evidently without a patron race. However, by the time of first contact with galactic civilization, humans had themselves raised chimpanzees and dolphins to sentience, giving the human race a claim to patron status. This claim is provisionally accepted by the major institutions of galactic civilization even as it is hotly contested by a number of senior patron races.

Galactic civilization holds humanity's claim of having evolved to sentience independently to be highly controversial at best, and an offensive heresy at worst. Some clans holding the latter view have actively conspired to have humanity's patron status officially vacated and to adopt the "wolfling" race themselves, thus gaining three sentient races and control of "fallow" genetic material: Earth's wealth of species with uplift potential. Only the conservative and ponderous nature of galactic institutions and the rivalry of other clans reluctant to see the Earth's races claimed by another have prevented this.

In the Worldwar novels by Harry Turtledove, Earth is the human homeworld and is attacked by the aliens known as The Race in 1942. All sides in the Second World War are forced to unify to fight this threat, and despite superior technology the Lizards (a human racial epithet for the aliens) are fought to a draw by 1944.

In 1962 another Race fleet arrives carrying a civilian colony force of nearly 100 million, in 1965 the Race and the German Reich fight a major war which Germany loses.

In 1994 humanity has caught up to the Race enough to send a slower-than-light starship to the Race's home world, where it arrives in 2031. Soon after another ship arrives, an FTL-capable ship, indicating that humanity has now surpassed the Race in technology.

• In the MOTHER / EarthBound video game series, Earth has different continent names and different cities but is still the same. Between 2000 and 2010, an alien known as Giygas took over the planet and destroyed most of the population. But, with the warning from a small alien from the future, a young hero named Ness saved the world from Giygas before he could attack.
• Many thousands of years later, all the population of Earth was killed – presumably because the planet was flooded – but some people went on the Nowhere Island before everything was destroyed. The island was protected because it contained a great power that was sealed long ago. The survivors hid their memories in an egg and created new ones, better ones so that they could have a normal life without remembering the world of before. Later in the game, Earth was again destroyed but then recreated as it was before. It is unknown if it means before the planet was flooded or before the game's tragic events.

In the Shannara series of books by Terry Brooks, the setting is a post-apocalyptic earth that was destroyed after a nuclear holocaust wiped out most of humanity and mutated the survivors into Men, Gnomes, Dwarves, and Trolls. Elves are also there, but according to Allanon's recounting of history, the Elves always existed in our current world. Before the Great Wars, as the nuclear holocaust is referred to, humans had advanced to a utopian society.

In the Death gate cycle series of books by Margaret Weis and Tracy Hickman, a nuclear holocaust led to the creation of a two mutant strains of humans who developed fantastic magical powers. Other races, such as Dwarves and Elves were also present, even in pre-holocaust Earth, but were hidden from humanity. In this universe, the Earth was destroyed by the Sartan, one of the magical races that evolved from humans.

An incomplete list of what Earth natives have been referred to in various Sci-Fi worlds: