Those obsessed with disasters can’t seem to get away from doomsday thoughts about asteroids. They fear them as irresponsible objects that can strike Earth any day and vaporize our civilization in one spell-binding inferno. (And they can’t be blamed, really. Every year, NASA detects about 1,500 near-Earth objects. Some graze us by.)
The private sector folks, at the other end, regard them as rich mines in the sky and would like to drill into them for their platinum and gold and molybdenum.
Asteroids are knobbly, irregular bodies, most of which bounce around in an enormous ring between the orbits of Mars and Jupiter. Pieces of planetary flotsam, essentially, they, like everything else in the solar system, go around the Sun, tumbling madly as they go along. The biggest of this family to date—Ceres—is about 600 miles across. The smallest can fit in a shoebox.
Kim Stanley Robinson has a creative vision for them in his science-fiction novel, “2312.” Some 150 years later, during the period called “Accelerando” (2160 to 2220)—a future Renaissance, of sorts, in which humankind had migrated out into the solar system—there came about a move to convert these cosmic refugees into terraria. (A terrarium is a glass enclosure for keeping either animals or plants.)
Robinson suggests hollowing out a russet potato-shaped asteroid, about 20 miles long (which is about six miles longer than Manhattan) and three miles wide, into an empty cylinder that has a wall about a mile thick. Any kind will do: those made of solid rock, metals, ice, or a combination of all three.
Because asteroids are pint-size worlds, they have no gravity. No atmosphere either. To bestow a centripetal force on them, set them spinning about their long axis, the rate of rotation, determined by the level of gravity desired on the inner surface of the tube. A series of powerful light bulbs—if one can call them that—moving at a set speed along the axis, will create a linear Sun. Day will break at the stern; end in the bow.
These structures remind us of Arthur C. Clarke’s “Rendezvous with Rama” (1973). The interior architecture of Rama, a space ark, is very like that of Robinson’s “asteroid terraria.” But it was the American aerospace engineer Dandridge Cole, who in 1963, thought of scooping out an ellipsoidal asteroid and converting its inner shell into a pastoral setting for a permanent, off-Earth colony.
Robinson transforms these cavernous, concave, inside-out worlds into ecological islands by recreating inside them either a Terran eco-region—woodlands, grasslands, deserts, chaparral, tundra—or creating something entirely new by combing two or three different biomes.
Any landscape is achievable. The Aymara is an “amazonia,” overgrown with cloud forest. The Copenhagen Interpretation is a “canal town with a gift economy.” Aspen is a “skiing paradise.” The Alfred Wegener is a mix of savannah and pampas: “Grass prairie and patches of forest arched like a giant Sistine Chapel overhead, a Sistine on which Michelangelo had painted a version of Eden.”
“Farmworlds” are devoted to producing a very large portion of the food feeding Earth’s population. The Moldova is a wheat bowl. These chambers can also be filled with an ocean, with or without archipelagoes. South Pacific 101 is such an “aquaria.” It has water sloshing against a huge chunk of ice that had been melted and refrozen to look like a giant hail from space.
Some also serve as spaceliners, ferrying passengers from one quadrant of the solar system to the other. The “blackliner” is a vessel, whose inside is as “black as could be.” Passengers flying in the “sexliner” could engage in any manner of sexual conduct as they pleased.
In the 24th century, there are 19,340 terraria pinballing around the solar system. Three-fourths of these operate as zoo worlds, dedicated to the conservation of breeds either radically endangered on Earth or have gone extinct in the wild.
The year 2312 marks the dawn of a new era. That’s when the animals return home, after having been absent from Earth for 200 odd years. When they come down, they come down together, all at once, in waves, in aerogel balloons: “Descending out of the western sky, dropping from low cumulus clouds, were caribou and elk and grizzly bear, all big brown dots with splayed legs.”