Så kallade ”rogue planets”, ensamma planeter som far omkring i rymden utan att cirkla runt en stjärna är något som är rätt vanligt i science-fiction. I verkligheten är det ovanligare, men det finns en känd, PSO J318.5-22 och flera möjliga eller troliga:
“Planets found by direct imaging are incredibly hard to study, since they are right next to their much brighter host stars. PSO J318.5-22 is not orbiting a star so it will be much easier for us to study. It is going to provide a wonderful view into the inner workings of gas-giant planets like Jupiter shortly after their birth,” said Dr Niall Deacon of the Max Planck Institute for Astronomy in Germany, co-author of the paper accepted for publication in the Astrophysical Journal Letters (arXiv.org).
I science fiction finns det i motsats till verkligheten en mängd exempel på fria ensamma planeter:
In the novel When Worlds Collide (serialised 1932) by Edwin Balmer and Phillip Wylie, Earth is first devastated, and then destroyed, by ”Bronson Alpha”, a gas-giant-sized rogue planet, orbited by ”Bronson Beta”, an Earth-sized satellite. In the film version (1951) of the novel, Bronson Alpha was reimagined as a dwarf star and renamed ”Bellus”, while Bronson Beta was designated ”Zyra.”
Fritz Lieber’s short story, A Pail of Air tells of Earth after it has been torn away from the Sun by a passing ”dark star”.
In the novel Wolfbane by Frederik Pohl and C. M. Kornbluth (originally serialised in Galaxy in 1957), a rogue planet, populated by strange machines known as Pyramids, steals the Earth from the Solar System, taking it off into interstellar space.
In Fritz Leiber’s novel The Wanderer, Earth encounters two ambulatory rogue planets. In the novel The Witches of Karres (1966) by James H. Schmitz, expanded from a 1949 novelette, the rogue planet Karres can be moved through space by means of psychic powers.
In the British science-fiction television series Space: 1999, the pilot episode (1975) has a rogue planet, Meta, coming near Earth. The series itself centers on the Moon being ejected from Earth orbit as well as from the Solar System, thereby becoming a rogue planet.
In the 1980 animated series Thundarr the Barbarian a ”runaway planet” passes between the Earth and Moon in the year 1994. The Moon is cracked in half and Earth’s civilization is destroyed. The series takes place two thousand years later, when the post-apocalyptic Earth is inhabited by mutants and wizards.
In the first series of Transformers comics published by Marvel Comics, the planet of Cybertron is a rogue planet that was dislodged from its original orbit in the Alpha Centauri system by weapons of mass destruction. In the Red Dwarf books, the Earth becomes a rogue planet when it is torn from its orbit by exploding sewage.
The homeworld of the Founders in Star Trek: Deep Space Nine is a rogue planet in a nebula; it has climatic conditions capable of supporting humanoid life. In theEnterprise episode ”Rogue Planet”, Enterprise happens upon a rogue planet with an Earth-like atmosphere.
From the 2nd season of Mainframe Entertainment’s War Planets cartoon onward, the titular planets were forced to become rogue planets in order to escape being consumed by the Beast Planet, which they achieved with colossal ”World Engine” propulsion systems created by a lost civilization.
In the online game Cartoon Network Universe: FusionFall, Earth is under attack by Fuse, the ruler of a possibly Saturn-sized rogue planet named Planet Fusion.
The video game Metroid Prime 2: Echoes (2004) takes place on a rogue planet named Aether.
In the Dalek Chronicles, comic strip stories featuring the Daleks, cyborg aliens from the long-running British science-fiction series Doctor Who, a rogue planet comes close to destroying the Dalek planet Skaro. However the Dalek Emperor is able to redirect the planet toward Mechanus, planet of the robotic Mechanoids, enemies of the Daleks. The planet is finally destroyed by Dalek weapons due to a robot sent to prevent a war between the Daleks and Mechanoids.