Overview
When the theme of interplanetary colonization first entered science fiction, the Asteroid Belt was quite low on the list of desirable real estate, far behind such planets as Mars and Venus (often conceived as a kind of paradise planet, until probes in the 1960s revealed the appalling temperatures and conditions under its clouds). Thus, in many stories and books the Asteroid Belt, if not a positive hazard, is still a rarely visited backwater in a colonized Solar System.
The prospects of colonizing the Solar System planets dimmed as they became known to be not very hospitable to life. However, the asteroids came to be imagined as a vast accumulation of mineral wealth, accessible in conditions of minimal gravity, and supplementing Earth's presumably dwindling resources—though the value of such minerals would have to be very high indeed to make such enterprises economically viable. Stories of asteroid mining multiplied after the late 1940s, accompanied by descriptions of a society living in caves or domes on asteroids, or (unscientifically) providing the asteroid with an atmosphere held in place by an "artificial gravity".
The idea of such isolated settlements, coupled with existing stereotypes of American mineral prospectors in the 19th century "Wild West", gave rise to the stock character of a "Belter" or "Rock Rat" – a rugged and independent-minded individual, resentful of state or corporate authority. Among such works is Ben Bova's Asteroid Wars series.
Another way in which asteroids could be considered a source of danger is by depicting them as a hazard to navigation, especially threatening to ships traveling from Earth to the outer parts of the Solar System and thus needing to pass the Asteroid Belt (or make a time- and fuel-consuming detour around it). In this context, asteroids serve the same role in space travel stories as reefs and underwater rocks in the older genre of seafaring adventure stories. And like such hazards, asteroids could also be used by bold outlaws to avoid pursuit. Representations of the Asteroid Belt in film tend to make it unrealistically cluttered with dangerous rocks, so dense that adventurous measures must be taken to avoid an impact, giving dramatic visual images which the true nearly empty space would not provide. One of the best-known examples of this is the Hoth system in Star Wars Episode V: The Empire Strikes Back.
In reality asteroids, even in the main belt, are spaced extremely far apart. Proto-planets in the process of formation and planetary rings may look like that, but the Sun's asteroid belt does not. (The asteroid belt in the HD 69830 system may, however.) The asteroids are spread over such a high volume that it would be highly improbable even to pass close to a random asteroid. For example, the numerous space probes sent to the outer solar system, just across the main asteroid belt, have never had any problems, and asteroid rendezvous missions have elaborate targeting procedures. The movie 2001: A Space Odyssey is unusual in that it does portray realistically the ship's "encounter" with a lone asteroid pair.
A common depiction of asteroids and comets in fiction is as a threat, whose impact on Earth could result with incalculable damage and loss of life. This has a basis in scientific hypotheses regarding such impacts in the distant past as responsible for the extinction of the dinosaurs and other past catastrophes —though, as they seem to occur within tens of millions of years of each other, there is no special reason (other than creating a dramatic story line) to expect a new such impact at any close millennium.
In earlier works, asteroids provided grist for theories as to their origin – specifically, the theory that the asteroids are remnants of an exploded planet. This naturally leads to SF plot-lines dealing with the possibility that the planet had been inhabited, and if so – that the inhabitants caused its destruction themselves, by war or gross environmental mismanagement. A further extension is from the past of the existing asteroids to the possible future destruction of Earth or other planets and their rendering into new asteroids.
Read more about this topic: Asteroids In Fiction