Editing Skein of Worlds:The Material Plane (section)

== The Spheres ==
There are three different types of spheres: the elemental spheres or planets, the positive energy spheres or suns and the negative energy spheres or black holes.

=== The Elemental Spheres ===
The elemental spheres, or planets, (usually) exist as a balance of the four elements. Each planet has an overall balance, but few planets are uniform. Different areas of a planet can have slightly different balances of the elements. This can be more obvious in some places than others. One of the clearest examples is a hot, dry desert where there is too much fire and not enough water. In places of especially high concentrations of one element vortices into the Elemental Tempest can form. A planet that is heavily unbalanced towards one element might gain a minor elemental trait. Rarely a planet may be lacking all four elements. Such a place would be a lifeless ball of cold, grey dust with a thin, unbreathable atmosphere.

==== Earth ====
Earth provides the solid ground. It is the most stable element, and rarely fluctuates much. Areas with too little earth are dusty or flowing. Quick sand or tar pits would be a localized example of this. Areas with too much earth would be very rocky and mountainous. Earth vortices tend to form in deep caves.

==== Air ====
Air provides, well... air. Air fluctuates a good deal as the winds come and go. Areas with too little air tend to make breathing difficult. This might manifest in any number of ways, from a simple lack of air, to stagnant air, to a lot of dust or water vapor suspended in what air there is. Areas with too much air tend to be very windy. Air vortices tend to form in large, high clouds.

Air exists even underground and underwater. Areas underwater with too little air can't support sea life very well. Areas underwater with too much air tend to manifest as underwater fountains of bubbles and the like.

==== Water ====
Water provides the oceans, lakes, rain and all other forms of moisture. Water doesn't fluctuate very rapidly, but its changes are sometimes pronounced, bringing dry days and rain, or drought and floods. Areas with too little water are simply dry. Areas with too much water tend to have a lot of lakes and heavy rains. Even areas underwater can lack water, even if that's hard to put into words. Such areas would be similar to areas that lack air aboveground, but are overall pretty rare. Water vortices tend to form in the deep ocean rifts.

==== Fire ====
Fire provides warmth. Areas with too little are cold, and areas with too much are hot, but fire is the most unstable element. It can fluctuate wildly even within a single day. Fire vortices mainly form in volcanoes.

=== The Positive Energy Spheres ===
The positive energy spheres, or suns, are the source of most light on the material plane. They're about the same size as a planet, but don't have much in the way of a surface or native life. Suns are mainly giant vortices into the positive energy plane.

If a planet was close enough to a sun, it might gain the minor positive-dominant trait. The sun would be very large in the sky, and even at night it wouldn't be as dark as in other places. Such a place wouldn't necessarily be any hotter though. Worlds with the positive-dominant trait would be hard places for normal civilizations to flourish since the forces of nature would be so much stronger.

=== The Negative Energy Spheres ===
The negative energy spheres, or black holes, are very similar to suns. They're about the same size, and don't have much of a surface or native life. The biggest difference is that a black hole is a vortex to the negative energy plane. Since it neither emits nor reflects light, it's very difficult to see, unless it's close enough to block the light from something else, such as a number of stars or a sun or planet.

A planet too close to a black hole would be a very dark place. Even during the day, it wouldn't be as bright, and at night the black hole could be seen as a great black disk in the sky. Any native life on such a planet would tend to grow and reproduce fairly slowly.

=== Planetary Systems ===
As previously mentioned, spheres tend to clump together into small systems. There's almost always at least one of each type of sphere in a system, and usually several more. (Planets tend to be about 3 times as numerous as either suns or black holes.)

Suns are easily visible from anywhere within a system, and even from other systems (as stars). Planets are usually visible from within the same system, although the further planets may require a telescope to see as more than a bright star. Black holes are rarely visible unless they eclipse something else.

''Note: I have no idea how spheres move within systems. Simply rotating in place isn't enough, but they have no particular reason to orbit each other in any simple way.''