The asteroids (or minor planets) mostly lie between the orbits of Mars and Jupiter. The first to be discovered was Ceres, identified by Giuseppe Piazzi (1746-1826) in 1801; three more, including Vesta and Pallas, were discovered in the same decade, and hundreds of thousands have now been catalogued. Only a few are over 150 km (100 miles) in diameter, the largest – Ceres, classified since 2006 as a dwarf planet rather than an asteroid – being some 700 km (435 miles) across. A once popular but now unfashionable theory originated by Heinrich Olbers (1755-1840) holds that the asteroids may be the debris of a planet torn asunder in some long-ago cosmic disaster. Gerald Heard's Reply Paid (1942) as by H F Heard speculates that the inhabitants unwisely "monkeyed with matter's make-up"; Robert A Heinlein's Space Cadet (1948) and a few moral tales of the 1950s – not to mention works of Pseudoscience to this day – state or suggest that nuclear Holocaust (after the expected fashion of World War Three) was responsible. The latter theory features prominently in James Blish's thriller The Frozen Year (1957; vt Fallen Star 1957), while the hypothetical war transcends time to continue in the mind of a human astronaut in "Asleep in Armageddon" (Winter 1948 Planet Stories) by Ray Bradbury, and long-ago nuclear testing by the people of Mars is blamed in Theodore R Cogswell's "Test Area" (February 1955 Fantastic Universe).
Some asteroids have extremely eccentric orbits which take them inside – in some cases well inside – the orbit of Mars or even that of the Earth. One such is featured in Arthur C Clarke's "Summertime on Icarus" (June 1960 Vogue), and the climax of James Blish's and Norman L Knight's A Torrent of Faces (1967) involves a collision between Earth and asteroid Flavia. Several thousand "near-Earth" asteroids have been catalogued. Cruithne, discovered in 1986, has an unusual orbit bringing it "close" to Earth (some 30 times the distance of the Moon) roughly annually: an expedition to this asteroid features in Stephen Baxter's Time: Manifold 1 (1999; vt Manifold: Time 1999).
In primitive Space Operas the asteroid belt tended to figure as a hazard for all ships venturing beyond Mars. Near misses and actual collisions were common; Isaac Asimov's "Marooned off Vesta" (March 1939 Amazing) begins with one such. Modern writers, however, generally realize both that the matter in the asteroid belt is very thinly distributed and that, as the asteroids all lie roughly in the plane of the ecliptic, it is easy to fly "over" or "under" them en route to Jupiter and the Outer Planets. This did not deter Piers Anthony, in Mercenary (1984), from quirkily modelling an asteroid-belt battle on the thirteenth-century Mongol invasion of Hungary (> History in SF) so closely as to neglect the fact that space has three dimensions and to treat "rivers" of dust and debris as impassable obstacles.
The asteroids figure most frequently in sf in connection with mining. In early pulp sf they became an analogue of the Klondike, where men were men and mules were second-hand Spaceships. Notable examples of this species of sub-Western space opera include Clifford D Simak's "The Asteroid of Gold" (November 1932 Wonder Stories), Stanton A Coblentz's "The Golden Planetoid" (August 1935 Amazing), Malcolm Jameson's "Prospectors of Space" (September 1940 Thrilling Wonder) and Jack Williamson's Seetee Ship (July and November 1942, January-February 1943 Astounding; fixup 1951; magazine stories and early editions as by Will Stewart). The analogy between the asteroid belt and the Wild West was soon extended, so that the lawless asteroids became the perfect place for interplanetary skulduggery, and they featured frequently in space-piracy stories of the kind popularized by Planet Stories; examples are "Asteroid Pirates" (August 1938 Astounding) by Royal W Heckman and "The Prison of the Stars" (November 1953 Planet Stories) by Stanley Mullen. The mythology was transplanted intact to the asteroids of other solar systems by E E Smith in Gray Lensman (October 1939-January 1940 Astounding; 1951) and co-opted into juvenile sf by Isaac Asimov in Lucky Starr and the Pirates of the Asteroids (1953 as by Paul French; vt Pirates of the Asteroids 1973). A gentler, more civilized asteroid mining community features in Robert A Heinlein's juvenile The Rolling Stones (1952; vt Space Family Stone 1969).
The use of the asteroids as alien worlds in their own right or as places fit for Colonization has been understandably limited: they are too small to offer much scope. Clark Ashton Smith's "Master of the Asteroid" (October 1932 Wonder Stories) and Edmond Hamilton's "The Horror on the Asteroid" (September 1933 Weird Tales) feature humans being marooned as a result of unfortunate collisions and meeting unpleasantly strange fates. The creature in Eden Phillpotts's Saurus (1938) was dispatched to Earth from the asteroid Hermes but, as he was still an egg at the time, he was unable later to give much of an account of life there. Asteroidal Shangri-Las are featured in Fox B Holden's "The Death Star" (April 1951 Super Science Stories) and Poul Anderson's "Garden in the Void" (May 1952 Galaxy), but in general the most interesting sf asteroids are those which turn out to be Spaceships in disguise, like the one in Murray Leinster's The Wailing Asteroid (1961). The asteroid/spaceship in Greg Bear's Eon (1985) turns out to be pregnant with all manner of astonishing possibilities including an internal Macrostructure of infinite extent. Jack Vance's "I'll Build Your Dream Castle" (September 1947 Astounding) depicts a series of asteroidal real-estate deals, but the feats of Terraforming involved stretch the reader's credulity. Charles Platt's Garbage World (1967) features an asteroid which serves as the dumping-ground for interplanetary pleasure resorts, but this is not to be taken too seriously. A scattered, tough-minded asteroid-belt society, the Belters, plays an important role in Larry Niven's Tales of Known Space series. Niven, in traditional fashion, sees the Belters as miners similar in spirit to the colonists of the Old West. One major work on this theme is Poul Anderson's Tales of the Flying Mountains (April 1963-September 1965 Analog as by Winston P Sanders; fixup 1970), an episodic novel tracing the development of the asteroid culture from its inception to its declaration of independence and beyond. (An earlier Sanders story set in the asteroid belt was "Barnacle Bull" [September 1960 Astounding/Analog].) A more up-to-date image of life on the belt frontier is offered in "Mother in the Sky with Diamonds" (March 1971 Galaxy) by James Tiptree Jr, and a notable modern Hard-SF story partly set on an unusual asteroid is Starfire (1988) by Paul Preuss. Stories in which asteroids are removed from their natural orbits include Bob Shaw's melodramatic The Ceres Solution (1981), in which Ceres is used to destroy the Moon, and Farside Cannon (1988) by Roger MacBride Allen, in which a similar but less desirable collision is averted.
The asteroids have become less significant as action-adventure sf has moved out into the greater galactic wilderness, but the idea that colonization of the solar system might involve the construction of purpose-built Space Habitats rather than descents into hostile gravity-wells has suggested to some writers that hollowed-out asteroids might have their uses; the most extravagant extrapolation of this notion can be found in George Zebrowski's Macrolife (1979), where asteroid habitats become a fleet of World Ships. Meanwhile the ancient pulp Clichés of asteroid-mining, claim-jumping and rebellious mining colonies are revived at some length in the Asteroid Wars subseries of Ben Bova's Tales of the Grand Tour sequence, beginning with The Precipice (2001). [BS/DRL]
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