Sculpture may be broadly defined as the art of representing observed or imagined objects in three physical dimensions. Sculpture may take the form of a biological organism, a statue, or a frozen light sculpture involving laser bursts preserved in a cube of photosensitive gel.3058 Sculpturing may be computerized in the creation: An artist designs a composition, say, in wax, and a machine-driven laser scalpel carves perfect copies in gold or stone, on radium or plutonium ingots, in miniature (as on a precious gem such as ruby or diamond), or in some architectural medium bigger than life.3059 Larry Niven’s "kdatlyno touch sculpture" could be constructed from a vibrating metal surface with variable textural and vibrational modes, but it would have to be extremely wear-resistant to survive fondling by millions of spectators’ hands. Similar in concept are the "tactoids" imagined by Arthur C. Clarke, an egg-shaped time-varying polytexturic handheld sculptural form that "does to the sense of touch what a kaleidoscope does to vision."1947
Sculptures need not necessarily involve the solid phase. Ivan Sanderson has described a unique form of dynamic water-sculpture that echolocating pelagic ETs might perfect:
Certain substances glow in total darkness owing to the release of photons caused by the breakdown of materials that have become "charged" through the absorption of sunlight. What we see in the sea is called luminescence and is produced chemically by living things, most notably by a tiny single-celled animal known as Noctiluca miliaris. These creatures light up when stimulated in various ways -- as mechanically by a ship’s bow waves and wake.... Ultrasonic vibrations of the required intensity could be generated by a large marine animal; indeed, dolphins and whales generate just such sounds. A beautifully coruscating whorl of light could be engendered by two porpoises, "singing" in close harmony.632
Sentient dolphins, in other words, could create optical interference patterns by echolocating in pairs near the same frequency, creating a dynamic light and-sound sculpture against a three-dimensional "screen" of luminescent microscopic lifeforms suspended in the ocean.*
Rainbows are a form of natural sculpture, and sentient creatures may be able to generate similar effects artificially. Radio vision aliens might construct a giant diffraction grating in the form of metal picket fences or using closely spaced electrically-conductive natural plant growth. Spaced 1-100 centimeters apart, such patterns would yield three or four orders of rainbow-like spectra as an observer moved from the front around to the side.
Sonic rainbows are also possible. One way to do it is to send white noise through a field of very large bubbles of air about 1 meter in diameter. Just as light slows in water droplets to form a natural optical rainbow in the sky, sound travels slower in the rising air pockets and is refracted to create what porpoises might call an "airbow." A more elegant technique involves the use of very small air bubbles. As R. McNeill Alexander has pointed out, when bubbles are blown in water a musical note can be heard because in the act of formation the bubble surfaces are set in vibration.230 The properties of pulsating bubbles are such that a bubble of 1 centimeter radius will emit sonic radiation at about 330 Hz; a bubble 0.1 centimeter in radius radiates at 3300 Hz; and so forth. Perhaps as part of an elaborate dance orchestration, sentient dolphins could generate distinctive three-dimensional patterns of glowing water-space ("glowing" in the sonic spectrum) by blowing exactly the right kinds of bubbles at the proper locations with accurate timing. Such a sonic airbow could take on any shape or color desired by the artist.
What about alien architecture? Sociobiologists are aware of many instances of homebuilding among nonhuman animals on Earth.3057,438 Octopuses live in "houses" which they either occupy fortuitously or build from scratch using rocks, pebbles, rusted cans, bottles, or anything else they can find on the sea floor.1000 The honeycomb hives of bees are perhaps the best known instance of animal architecture, and Karl von Frisch has demonstrated that the hexagonal shape of the honeycomb is mathematically optimal in that it encloses the most volume using the least materials.438 And until the coming of mankind the monolithic cities of the termites represented the greatest modification of the natural landscape wrought by animal life. Built of porous clay and oriented exactly along an east-west axis to minimize the heating effects of direct sunlight, termite mounds often reach heights of more than 5 meters and occasionally have diameters as wide as 30 meters across.1000
So we see that both solitary and gregarious creatures on this planet make use of architectural structures. Virtually all human societies utilize some form of shelter, even in the Pacific islands where the climate is so benign that no elaborate housing is really needed. These facts argue strongly for the ubiquity of architecture among extraterrestrial societies.3060
What are the gross physical limits to such construction on any world? Gravity is the first problem.20 According to the Square-Cube Law, the mass of a building which must be supported by its foundation increases as the cube of the linear dimension, whereas the supportive area of the foundation increases only as the square. The compressive strengths of natural and artificial building materials are well known,924,1852 so it is a simple matter to calculate the maximum permissible sizes of structures on other worlds. Maximum height of a given design will vary inversely with gravity. In other words, the highest building on a 2-gee planet can only be about half as high as a similar structure with similar materials constructed here on Earth.
Another major environmental factor is geological activity.61 As we discovered in an earlier chapter, massive planets have more internal energy available to drive thermal convection currents in the mantle. This means more earthquakes. Xenologists therefore expect to find sqatter, more sturdy and temblor-proof buildings on heavy worlds than on light ones, since quakes topple buildings more easily the higher their centers of gravity are from the ground.926,925 This conclusion is reinforced by the observation that high gravity and tectonic activity appear to be highly correlated.
Still another important consideration is wind velocity. Planetologists recognize that planetary rotation is related to wind speed -- generally the faster the rotation, the faster the winds. Also, an empirical relation derived from data from the bodies in our solar system indicates that planetary mass and rotation are also correlated (for reasons unknown) -- the more massive the planet, the shorter its day. Putting these two results together, xenologists expect that massive high-gravity worlds should have faster winds than less massive, low-gravity worlds.
Tall, wispy architectures are less likely on planets with ferocious winds.925 Nevertheless, as Donald Stern once pointed out to the author, architectural forms on high-wind-velocity planets can still have as much variation and height as on Earth:
Wind factor can be compensated for. Under high wind conditions it is not necessary to weight a structure down to make it immovable. A good terran example of this is the Mongolian yurt, a dome-shaped structure of wood latticework covered with hides and a felt-like material ½ cm thick. This structure weighs only a few hundred pounds and is designed to be fairly portable. Yet it can withstand wind velocities up to 140 kph on the open steppes. Even tall structures should be possible under such conditions. (See "Wicker Wonderland" in Keith Laumer’s Galactic Diplomat.) Spire-like city structures could be constructed to serve as a graduated series of windbreaks. They could conceivably be semiflexible, but might prove more livable if they could be rigidly fixed in a giant latticework or grillwork system that would still be capable of breaking up the force of the wind. ("Galloping Gertie," the Tacoma Narrows bridge, collapsed because solid panels were used in the cable suspension; it was later rebuilt using a latticework system.) If spread across the face of a high-wind planet, such structures could serve to lower the wind factor by several orders of magnitude.2976
Another possibility for windy worlds is to construct buildings in the shape of vertical airfoils, streamlined, gimballed and pointing into the wind for maximum stability.**
Rather than using static construction materials, it has been suggested that ETs may wish to employ what is called "biotecture" or biological architecture. One biostructure grown by architect Rudolf Doernach near Stuttgart, Germany consists of living hazel trees bent into an arched framework over which dense foliage plants have been grown to form protective walls. Frank Lloyd Wright once designed a mile-high skyscraper with a foundation patterned after the taproot systems by which many plant species anchor themselves to the ground. Biotects dream of using genetically altered plants to grow predesigned habitable shapes, and crystalline minerals chemically treated to grow into specific forms. Marine animals such as shellfish and coral could be genetically doctored and used in biotecture. As one science fiction writer describes it:
A genetic manipulation of ordinary sea coral, it was the cheapest building material known. The only real cost was in the plastic balloon that guided the growth of the coral and enclosed the coral’s special airborne food. The remnants of the shaping balloon gave all architectural coral buildings their telltale bulge. The exposed walls can be polished to a shining pink sheen, Even after sunset the house glowed softly.231
Inside living houses we might find living furniture! A genetically altered canine, bred for patience and furriness, could serve as a self-moving chair (the "chairdog"); another variety could be used as a bed with a comfy conformable surface (the "bedog");2615 a modified Galapagos tortoise species could serve as living tables and desks (the "tableturtle"); and so forth.
A wide variety of unusual architectural forms have been proposed by many writers, including the cryotectural Ice City,3065 Ferrocement (Ant Farm) Structures,3062 Aerotecture,3062 Cybertecture,3062 Self-Building Symbiotic Structures,3065 the Sensitive House,3064 the Crystal Caves,3064 Archigram and Modular Habitats,3062 Chemitecture and Laser Architecture,3065,3063 Urban Microclimates,3062 Edible Houses,3064 Terratecture and Geotecture,3061 Green house Cities,3062 Kinetic Architecture,3063 the Biopolis,3067 Ecopolis,3062 and the Biomorphic Biosphere Megastructure.3066 Extraterrestrial architects and biotects may exploit these and countless other remarkable design approaches in the construction of buildings and habitats on other worlds.
* The gaseous phase is also a possibility -- "weather sculpture" has been suggested by at least one science fiction writer.3077
** Environmental and sensorial factors may also be significant. Olfactory beings may design "smell vents" into their buildings rather than windows and skylights.1000 The equivalent for tactile ETs would be vibration transducers mounted into walls. And radio-visioned aliens inhabiting starless planets should have a most unique variety of interior lighting. Since radio illumination percolates up from the ground, and deeper means hotter and thus brighter, ETs might drill vertical shafts to bring forth "radio light." Houses might be built around these radio wells.