Spacemist

Filling dreamspace between the worlddisks of the plane of Charés is the spacemist (often referred to in the plural as "spacemists", and sometimes called "dreammist"), an insubstantial transparent colored vapor that extends indefinitely in all directions. The color of the spacemist varies in different locations, and may take on different patterns and movements. In some areas of dreamspace, there are well-defined blocks of constant color; in others the space is filled with chaotic, writhing swirls and interplays of everchanging hues. Most areas of dreamspace lie somewhere in between, as colors gradually blend into each other and slowly shift over time. Naturally, the more constant the colors of the spacemists, the easier they make navigation through those areas.

The spacemist is somewhat thicker than air, which tends to slightly slow movement within it. Though it varies somewhat, on average the spacemist's viscosity is about five times that of air at normal atmospheric pressure. Despite its thickness, spacemist is easily breathable. It has a slight flavor to it, which varies by the color; some bright red mist, for example, has been compared to nutmeg (though the resemblance is rather distant), some blue to some sort of cheese, and a certain shade of green is said to taste vaguely like brown sugar.

The color of the spacemist seems to have no other discernable effect; all colors of mist are equally transparent and immaterial, and although various suggestions have been bruited about different long-term effects of exposure to different colors of mist, or effects that they may have on magic cast within, none of these ideas is known to have been conclusively proven.

One popular (and plausible) hypothesis about the reasons for the different colors is that, whether or not it affects the casting of magic within, the color of the spacemist is affected by nearby magical energies. On Rachoy, magic comes from dreams, so the ambient magic will be greatest where there are the greatest numbers of dreamers--which is to say, on the worlddisks. In the presence of such strong and everpresent magical energy, the theory goes, the mists thin out and lose their color--becoming air. However, the effects of the energy go beyond that, and the color of the mist beyond the interface between the air and the spacemist (the so-called dreamsea) is also largely determined in some way by something about the nature of the nearest worlddisk, or other source of significant ambient magical radiation--though other, more distant, worlds may also play a part.

In principle, this hypothesis may be testable. If in some way a world was found that was undergoing a drastic and sudden change in its population makeup, and the colors of the nearby dreammists were measured before and after, any change could be observed and correlated with what was going on in the world. In practice, while not impossible, such an experiment would be very difficult to carry out. Certainly some worlds do undergo such drastic changes, but seeking out such a world would not be easy, and for the experiment to yield any reliable results multiple such worlds should be found and observed. Furthermore, there's nothing to say that the effect on the spacemist would necessarily be instantaneous, so long-term observations might be necessary to see any results. Add in the difficulty of factoring in the effects of neighboring worlds, and it's easy to see why this hypothesis remains unverified.