Alternate history is a genre of speculative fiction of stories in which one or more historical events occur and are resolved differently than in real life. As conjecture based upon historical fact, alternative history stories propose What if? scenarios about crucial events in human history, and present outcomes very different from the historical record. Alternate history also is a subgenre of literary fiction, science fiction, and historical fiction; as literature, alternate history uses the tropes of the genre to answer the What if? speculations of the story.
The multiverse is a hypothetical group of multiple universes. Together, these universes comprise everything that exists: the entirety of space, time, matter, energy, information, and the physical laws and constants that describe them. The different universes within the multiverse are called "parallel universes", "other universes", "alternate universes", or "many worlds".
A fictional universe, or fictional world, is a self-consistent setting with events, and often other elements, that differ from the real world. It may also be called an imagined, constructed, or fictional realm. Fictional universes may appear in novels, comics, films, television shows, video games, and other creative works.
Galactic empires are a common trope used in science fantasy and science fiction, particularly in works known as 'space operas'. Many authors have either used a galaxy-spanning empire as background or written about the growth and/or decline of such an empire. The capital of a galactic empire is frequently a core world, such as a planet relatively close to a galaxy's supermassive black hole, which has advanced considerably in science and technology compared to current human civilization. Characterizations can vary wildly from malevolent forces attacking sympathetic victims to apathetic bureaucracies to more reasonable entities focused on social progress and anywhere in between.
A parallel universe, also known as a parallel dimension, alternate universe, or alternate reality, is a hypothetical self-contained plane of existence, co-existing with one's own. The sum of all potential parallel universes that constitute reality is often called a "multiverse".
The Freedom Fighters is a superhero team appearing in American comic books published by DC Comics. The original six characters were the Black Condor, Doll Man, the Human Bomb, the Ray, the Phantom Lady, and Uncle Sam. Although the characters were created by Quality Comics, they never were gathered in a group before being acquired by DC. The team first appeared in a Justice League of America/Justice Society of America team-up, which ran in Justice League of America #107–108, written by Len Wein and drawn by Dick Dillin. Their own ongoing series premiered with Freedom Fighters #1, written by Gerry Conway and Martin Pasko, and drawn by Ric Estrada.
The Virgin New Adventures are a series of novels from Virgin Publishing based on the British science-fiction television series Doctor Who. They continued the story of the Doctor from the point at which the television programme went into hiatus from television in 1989.
The Anti-Monitor is a supervillain appearing in American comic books published by DC Comics. He served as the main antagonist of the 1985 DC Comics miniseries Crisis on Infinite Earths and later appears as an enemy to the Green Lantern Corps and the Justice League.
GURPS Infinite Worlds is a supplement for the Fourth Edition of the GURPS role-playing game, published by Steve Jackson Games in 2005 and written by Kenneth Hite, Steve Jackson, and John M. Ford. It expands upon the campaign setting of conflict between the Infinity Patrol, which is the dimension-jumping agency on "our" Earth, referred to as Homeline, and Centrum across a multiplicity of alternate history Earths. This was presented in the Fourth Edition GURPS Basic Set.
Cosmic pluralism, the plurality of worlds, or simply pluralism, describes the belief in numerous "worlds" in addition to Earth, which may harbour extraterrestrial life.
"Random Quest" is a science fiction short story, which is also a love story, by British writer John Wyndham. It was included in his 1961 collection Consider Her Ways and Others. It has been dramatised three times, twice under its original name and once as Quest for Love.
Timewyrm: Exodus is an original Doctor Who novel, published by Virgin Publishing in their New Adventures range of Doctor Who novels. It is a sequel to author Terrance Dicks' 1969 Second Doctor story The War Games as well as the second part of the ongoing four novel Timewyrm narrative.
The Multiverse, within DC Comics publications, is a "cosmic construct" collecting many of the fictional universes in which the published stories take place. The worlds in this multiverse share a space and fate in common, and its structure has changed several times in the history of DC Comics. The Multiverse was originally created by Perpetua, who is the mother of the Monitor, Anti-Monitor and World Forger.
In speculative literature, the Hypothetical Axis victory in World War II is a common subject in works of alternative history (fiction) and of counterfactual history (non-fiction) which examine public and private life in the lands conquered by the Axis powers — Nazi Germany, Imperial Japan, and Fascist Italy — in the Second World War (1937–1945).
"End of an Era" is an American comic book story arc that was published by DC Comics, and presented in Legion of Super-Heroes vol. 4, #60-61, Legionnaires #17-18, and Valor #22-23. It was written by Mark Waid, Tom McCraw and Kurt Busiek, with pencils by Stuart Immonen, Ron Boyd, Chris Gardner and Colleen Doran. A tie-in to the Zero Hour: Crisis in Time miniseries, it is the final story arc in the Legion of Super-Heroes' original timeline, and marks the end of 36 years of unbroken Legion continuity.
The Multiversity is a two-issue limited series combined with seven interrelated one-shots set in the DC Multiverse in The New 52, a collection of universes seen in publications by DC Comics. The one-shots in the series were written by Grant Morrison, each with a different artist. The Multiversity began in August 2014 and ran until April 2015.
Rumfuddle is a science fiction story by Jack Vance published in ‘’Three Trips in Time and Space’’, a 1973 anthology of original science fiction novellas edited by Robert Silverberg. In Rumfuddle, a genius scientist named Alan Robertson has discovered that there are an infinite number of parallel universes. He creates a machine that can inexpensively access portals between universes that are similar to our own, which he calls “cognates”. At first, this technological leap leads to positive effects, such as infinite access to natural resources from other parallel worlds. As time goes on, though, people realize that this new power may have negative consequences.