Wolk

A wolk (pronounced /woʊk/ or /woʊlk/) is a large landmass completely surrounded by gas or by nothingness, and with more or less uniform gravitational force on its surface—or possibly with gravity acting in opposite directions on opposite sides. Essentially, a wolk is to a shee as a continent is to an island. Like an earthbound continent, a wolk may house a diverse variety of complex ecosystems, and be the site of multiple nations—though it may also be a barren and uninhabited wasteland.

There are many variants of the word "wolk" that are also in fairly frequent use, and in fact in certain areas may be preferred over the usual form. These include "volk", "wolken", "volken", "wolkin", "welken", and "welkin". (The fact that this last form is identical with an archaic or poetic word meaning "sky" is not coincidental; the words come ultimately from the same Old English root.) Nevertheless, overall "wolk" is the form most favored by geographers.

As is the case with a shee, there are a few additional criteria that a body must meet before it is considered a wolk. Generally, a wolk must be relatively near other similar masses of comparable or greater size. A body surrounded by gas or void without any other bodies nearby that aren't several orders of magnitude smaller is not considered a wolk, but a world in and of itself. The worlddisks of Charos, for example, are certainly large landmasses completely surrounded by gas (the dreammist that pervades the plane) and therefore would otherwise meet the qualifications of a wolk, but are not conventionally referred to as such. Furthermore, it is generally assumed that a wolk must have gravity acting in a uniform direction on its surface—or, at the very least, in two opposite directions on a flat wolk's two sides. If the gravity simply points radially toward the body's center, it is not considered a wolk. Thus, for example, the Earth's moon is not considered a wolk; it may be surrounded by vacuum and near a much larger body, but it is ruled out by the gravitational criterion (though its distance from the Earth is great enough that perhaps not all geographers would consider it a wolk anyway). A landmass almost surrounded by gas or void, but with some narrow connections to a greater body that clearly are not enough to support the landmass's weight, is sometimes called a "semiwolk".

There is no firm cutoff for the minimum area a shee has to have before it is considered a wolk. A very rough rule of thumb is that a mass with an area larger than five million square kilometers is more likely to be considered a wolk, and one with an area smaller than this a mere shee, but there are certainly many exceptions. More practically, the dividing line generally depends on the distribution of areas among gas-(or void-)surrounded landmasses in a particular world; if there's a pronounced gap in the distribution anywhere in the range of several million square kilometers or so, then the landmasses above the gap, and only those, will usually be considered wolks. In some rare cases, a particularly large landmass may be considered to comprise two or more wolks, though there's no systematic basis for this.

Origins

Wolks may be of natural or artificial origin. Natural wolks, of course, require either magic, or some suitable physical laws that would keep the wolk suspended apart from its neighboring bodies. Nonmagical wolks are possible in Ses, due to the way that weight and gravity work there, but not in Xi. (While it's conceivable for a large body to be suspended above a larger body in Xi through magnetism, it's hard to propose any method by which such an arrangement could naturally occur.) Magical wolks may arise through various forms of spontaneous enchantment.

Artificial wolks may be created for many reasons. Gods may create such wolks to populate with mortals to worship them, or mortals may create them as new homes or as places of exile. Powerful empires and mages may conceivably create them just as a show of their abilities. Of course, given the sheer size of a wolk, it takes a civilization with considerable power to construct such a thing, and artificial wolks are unlikely to be found on otherwise relatively undeveloped worlds—unless they are a relic of a past civilization that has since fallen, or were introduced by foreign visitors.

The creation of an artificial wolk generally occurs in one of three ways. For one, the substance to form the wolk may be lifted up from the land below. This, of course, leaves a barren scar where the land came from, though one that in time is likely to fill in, and over a long enough period may become indistinguishable from its surroundings. Wolks formed in this way will, of course, have a similar makeup and ecosystem to the areas their land was taken from, at least at first; if the wolk is around for long enough, its inhabitants may come to diverge considerably from their origins. Second, the substance to form the wolk may be transported there from elsewhere, perhaps from some other world or plane, probably by translocation. Creating a wolk in this way, however, risks introducing to the world invasive species that may prove problematic. Third, the wolk may be assembled out of collected materials, though because of a wolk's sheer size this is less feasible than it is for a smaller shee.

There are other ways wolks may be constructed. Living wolks may be grown and nurtured; wolks can be magically created wholesale ex nihilo. Still, on most worlds these methods are relatively rare.

Motion

Wolks may or may not be in motion relative to adjacent landmasses. Many wolks hang in a constant position over a landscape below, forming an unmoving landmark. Others move, with varying speeds, in circles or other patterns, their coming and going regular and predictable. Still others meander randomly, staying perhaps within a confined area but their peregrinations within that area impossible to anticipate.

Whether or not a wolk moves is usually determined by its creation. Most natural wolks are stationary, though, again, it may depend on the laws of physics where the wolks are. Artificial wolks may be made to move so that their inhabitants can see or interact with different lands below, or simply so that they don't cast one area in perpetual shadow. It may happen, though, that a wolk initially stationary somehow comes "unmoored" and starts to wander, either because of an enchantment placed on it or perhaps because of some unexpected ambient magical effect. Conversely, it's also impossible that the course of a moving wolk could be changed, or the wolk stopped entirely.

Below the wolk

More so than the relatively small shees, wolks can have a profound effect on the lands below them, especially stationary wolks. Most obviously, if (as is usually the case) the world is lit from above, a wolk may keep the area beneath it in perpetual shadow, preventing plant growth and leading to a zone of deathlike darkness and gloom. If this is the case, some nearby individuals may have an interest in moving or destroying the wolk just to open up more habitable land. Such a situation is not inevitable, however; some wolks emit, transmit, or bend light to ensure that it does reach the areas below them, and of course in some cases the areas below a wolk may be inhabited by scotophilic organisms that don't need light anyway.

Unlike a stationary wolk, a moving wolk of course would not leave the area under it perpetually shadowed. However, if the wolk is moving slowly enough, it may still overshadow areas long enough to endanger plant life there and be otherwise problematic. In fact, in some ways slow-moving wolks may turn out to be more dangerous than stationary wolks, since they can put larger areas in peril—particularly if their movement is erratic enough to make it unforeseeable exactly when they might appear.

Depending on what exactly the wolk holds, the shadow it casts may not be the only significant effect it has on its environs. Objects falling from the wolk may impact the land below, and magical emanations might affect it in other ways.

Makeup

Most wolks are made of similar material as the world below. Depending on how the wolk was created, however, this need not necessarily be the case. Wolks vary in composition much less than smaller shees, probably mainly because of the greater material needed; exotic materials may be much more easily acquired in the relatively small amounts required for a shee than in the continent-sized sheets for a wolk. Nevertheless, while most wolks are composed primarily of simple earth and stone, exceptions do occur, and some wolks do exist made of very unusual materials.

Though it's not impossible, in principle, for a wolk to be of any shape, including spherical or irregular, in practice the great majority of wolks are flat (at least on the top side), with gravity acting perpendicular to their surface. Most wolks have a single gravitational direction (and are said to be monogravitational), but there are bigravitational wolks that have two sides with opposite gravitational directions, typically one the same as the gravity on a nearby landmass and one, on the bottom of the wolk, in the opposite direction, so that it's possible for objects to rest and organisms to live on either side of the wolk.

Some wolks also have extensive interior hollows, with perhaps more total area in multiple layers of tunnels than on the wolk's exterior surface. These interior cavities may also bear life and useful resources. Typically gravity in the interior of the wolk is the same as on the top, though in some bigravitational wolks part of the interior has gravity matching each side of the wolk. A few exceptional wolks have no gravity in their interiors.

Given that some of the substance and contents of the wolk inevitably falls or is worn off, most wolks have some mechanism for replenishing their mass, although some do simply gradually erode away. Some wolks are replenished by simple magical generation of more substance, or translocation from elsewhere; others gain mass that falls from other wolks higher up. Many wolks are replenished by living beings that for some reason as part of their life cycle bring mass to the wolk from the surrounding world.

Life

Wolks are often inhabited, though often bearing very different ecosystems than the worlds below. Very often the life on a wolk is transplanted from the nearby world by ellogous beings that travel there, either intentionally or as stowaways on their vessels. And, of course, the creators of an artificial wolk may seed it with life at the time of its creation.

It is not necessarily the case, however, that life comes to a wolk by ellogous hands. A wolk may be first settled by life forms with the power of flight, or that are light enough (at least in their embryonic form) to be carried by the wind. Given sufficient time, such life can evolve and diversify into forms that bear little resemblance to their forebears and obscure their origins. On a wolk amply provided with water and appropriate chemicals, it's even possible that life may arise independently of that on the rest of the world. A few worlds have even been discovered where life actually first originated on a wolk before spreading to the world below.