Asteroids have appeared in fiction since at least the late 1800s, the first one—Ceres—having been discovered in 1801. They were initially only used infrequently as writers preferred the planets as settings. The once-popular Phaëton hypothesis, which states that the asteroid belt consists of the remnants of the former fifth planet that existed in an orbit between Mars and Jupiter before somehow being destroyed, has been a recurring theme with various explanations for the planet's destruction proposed. This hypothetical former planet is in science fiction often called "Bodia" in reference to Johann Elert Bode, for whom the since-discredited Titius–Bode law that predicts the planet's existence is named.
By the early 1900s, the asteroids started making more regular appearances. The asteroid field has often been depicted as having asteroids so close together as to impede travel, though this became less common later in the century as writers started portraying a more realistic density. Because the asteroids are so small, they are usually not depicted as inhabited—though in some works they are nevertheless habitable. In other works they are made so by human activity, be it terraforming or hollowing out to create habitats on the inside. The latter concept has also been used for turning asteroids into spacecraft. Human activity in the asteroid belt has featured frequently since the pulp era of science fiction, particularly in the form of asteroid mining. Space piracy also debuted as a theme around the same time. In works where the asteroid belt is settled by humans, it is often conceptually similar to the Wild West.
The threat of impact events by asteroids has been a recurring theme. It received successive boosts in popularity following the 1980 publication of the Alvarez hypothesis about the extinction of the dinosaurs and the 1994 impact of Comet Shoemaker–Levy 9 on Jupiter. Many stories involve attempts to alter asteroid trajectories to avert such collisions, while in some stories they are instead caused intentionally.
Remnants of a planet
The first asteroid—Ceres—was discovered by Giuseppe Piazzi in 1801. For the rest of that century, however, asteroids rarely appeared in fiction—writers preferring the planets as settings. When German astronomer Heinrich Olbers discovered a second asteroid—Pallas—in the same orbit in 1802, he theorized that these objects were remnants of a planet predicted by the Titius–Bode law to exist between Mars and Jupiter that had somehow been destroyed. This became a popular explanation for the existence of the asteroid belt, though it has since been superseded by the notion that the material never coalesced into a planet in the first place. In astronomy, this hypothetical former fifth planet is known as Phaëton; in science fiction, it is often called "Bodia" after Johann Elert Bode. An early science fiction work that mentions this explanation for the origin of the asteroids is Robert Cromie's 1895 novel The Crack of Doom, which describes the release of energy stored in atomic nuclei a few thousand years ago as the culprit.
By the pulp era of science fiction, Bodia was a recurring theme. In these stories it is typically similar to Earth and inhabited by humans, often advanced humans and occasionally the ancestors of humans on Earth. Interplanetary warfare with Mars causes the destruction of Bodia—and indirectly, the end of civilization on Mars—in Harl Vincent's 1930 short story "Before the Asteroids". An internal disaster resulting in the explosion of the planetary core is responsible in John Francis Kalland's 1932 short story "The Sages of Eros". In Leslie F. Stone's 1934 short story "The Rape of the Solar System", war with Mars over the colonization of then-uninhabited Earth results both in the partial destruction of Bodia, thus creating the asteroids, and the displacement of the largest fragment to a much wider orbit to create Pluto, while the settlers on Earth eventually become humanity.
Following the invention of the atomic bomb in 1945, stories of this planetary destruction became increasingly common, encouraged by the advent of a plausible-seeming means of disintegration. Robert A. Heinlein's 1948 novel Space Cadet thus states that the fifth planet was destroyed as a result of nuclear war, and in Ray Bradbury's 1948 short story "Asleep in Armageddon" ( "Perchance to Dream"), the ghosts of the former warring factions infect the mind of an astronaut stranded on an asteroid. Several works of the 1950s reused the idea to warn of the dangers of nuclear weapons, including Lord Dunsany's 1954 Joseph Jorkens short story "The Gods of Clay" and James Blish's 1957 novel The Frozen Year ( Fallen Star). In Jack Williamson's 1942–1951 Seetee series an antimatter explosion is to blame, and in Theodore Cogswell's 1955 short story "Test Area", the destruction results from a nuclear test conducted by the inhabitants of Mars, while in Heinlein's 1951 novel Between Planets the technology that caused the destruction has been lost to time. The planet's destruction by Martians is also mentioned in Heinlein's 1961 novel Stranger in a Strange Land, and implied to have been caused using supernatural powers. The 1977 novel Inherit the Stars, the first in James P. Hogan's Giants series, revisits the theme of the fifth planet—here called "Minerva"—being destroyed by nuclear war.
In Raymond Z. Gallun's 1950 short story "A Step Farther Out", valuables from the destroyed civilization are recovered, and in Harry Harrison's 1969 novel Plague Ship, an ancient virus is found in the asteroid remnants. Paul Preuss's 1985 short story "Small Bodies", where fossils are found on an asteroid, is a late example of the destroyed planet theme; it has otherwise largely been relegated to deliberately retro works such as the 1989 tabletop role-playing game Space: 1889. A variation on the theme appears in Clifford D. Simak's 1973 short story "Construction Shack", where the asteroids are leftover material originally intended for the construction of a fifth planet.
Navigational hazard Asteroids started making more frequent appearances in fiction in the early 1900s, and these works tended to depict the asteroid belt as a region that must be navigated carefully lest one's spaceship should collide with one of the asteroids. The space opera subgenre in particular often features this motif. In Isaac Asimov's 1939 short story "Marooned off Vesta", a group of astronauts run into this danger, and in Williamson's 1949 novel Seetee Shock, a region of space is virtually impassable for this reason. The problem is circumvented in Mark Clifton's 1960 novel Eight Keys to Eden by exploiting the third dimension of space, since the asteroids are mostly located in the plane of the ecliptic.
Later works mostly recognize that the individual asteroids are very far apart: the average distance between them is comparable to the Earth–Moon distance. Accordingly, they pose little danger to spacecraft, though this need not necessarily be the case in asteroid fields outside of our Solar System. Nevertheless, the idea of a thick asteroid field that poses constant danger to any spaceship within it recurs in the 1979 video game Asteroids, and close-quarter dogfights between spacecraft among asteroids appear in the 1980 Star Wars film The Empire Strikes Back and the 1995–1996 television series Space: Above and Beyond. A densely packed extrasolar asteroid field in the Alpha Centauri system also appears in the 1981 episode "The Golden Man" of the television series Buck Rogers in the 25th Century. Piers Anthony's 1984 novel Mercenary goes so far in its adaptation of the 1241 Mongol invasion of Hungary to the asteroid belt that it treats space as two-dimensional and constrains movement accordingly.
Native life
Alien life on asteroids appears only rarely in fiction, owing to their small size. An early example is found in Konstantin Tsiolkovsky's 1896 short work "On Vesta", where the lifeforms are intelligent and technologically advanced. Humans stranded on an asteroid encounter hostile aliens in Clark Ashton Smith's 1932 short story "Master of the Asteroid" and Edmond Hamilton's 1933 short story "The Horror on the Asteroid". The titular reptilian of Eden Phillpotts's 1938 novel Saurus comes to Earth from an asteroid as an egg before hatching, and an asteroid is likewise the homeworld of the title character in Antoine de Saint-Exupéry's 1943 novel The Little Prince. Alien plant life on an asteroid turns it not only habitable but paradisiacal in Poul Anderson's 1952 short story "Garden in the Void", and the inhabitants of an asteroid in Philip K. Dick's 1953 satire "Piper in the Woods" persuade human visitors that being a plant is preferable to being human, while a silicon-based lifeform from an asteroid appears in Asimov's 1955 short story "The Talking Stone". In Fredric Brown's 1957 fix-up novel Rogue in Space, an asteroid is itself alive. The notion that asteroids might harbour microbial life, possibly even deadly pathogens that could be transferred to Earth either directly by impacting the planet or indirectly via astronauts visiting the asteroid, also surfaces occasionally.
Human presence A new concept was introduced in the pulp era of science fiction: asteroid mining. This quickly became the most popular fiction use for the asteroids, and the asteroid belt was often portrayed as the setting of a space version of the Klondike or California gold rush in works like Simak's 1932 short story "The Asteroid of Gold", Stanton A. Coblentz's 1935 short story "The Golden Planetoid", and Malcolm Jameson's 1940 short story "Prospectors of Space". Along with this outer-space analogy of the Western genre came the introduction of space piracy to the asteroids in works like Moore Raymond's 1934 short story "Scouts of Space" and Royal W. Heckman's 1938 short story "Asteroid Pirates", as well as stories of stranded astronauts as in John Wyndham's 1933 short story "Exiles on Asperus" and the above-mentioned "Master of the Asteroid" and "Marooned off Vesta". These themes continued to appear in the decades that followed: Heinlein's 1952 novel The Rolling Stones portrays a community of asteroid miners, Asimov's 1953 novel Lucky Starr and the Pirates of the Asteroids features space pirates, and Arthur C. Clarke's 1960 short story "Summertime on Icarus" depicts an astronaut stranded on the asteroid Icarus as it makes a close approach to the Sun.
The prospect of colonizing the asteroids was limited by their small size, though this did not stop some works such as the 1959–1964 science fiction anthology series The Twilight Zone from portraying asteroids with breathable atmospheres and Earth-level gravity. Somewhat more realistic portrayals of human-habitable asteroids involve terraforming, as in Paul Ernst's 1931 short story "The Planetoid of Peril" and Jack Vance's 1947 short story "I'll Build Your Dream Castle", or hollowing them out to create space stations or habitats, as in Heinlein's 1939 short story "Misfit". In "I'll Build Your Dream Castle", the terraformed asteroids are sold as luxury real estate, while in Charles Platt's 1967 novel Garbage World, a terraforming effort gone wrong results in an asteroid being used as a dumping place for the Solar System's garbage.