The Astral Sea

The Astral Sea, also known as the Astral Plane or the Outer Plane, is a dimensional plane within the local Planar System, which acts as a sort of causeway between many of the various planes. Along with the Ethereal Plane, it is one of two planes from which other dimensions can be easily accessed by means of mundane travel. As such, it is hotly contested territory, and throughout the millennia, dozens of individuals have tried to control movement to and from the Astral Sea.   To most visitors, the Astral Sea is shaped like an enormous, infinitely long hollow tube, with inhabitants traveling along the interior surface. Thus, the other side of the "world" is always visible directly overhead, an experience which most natives of the Material Plane find extremely disorienting. Ambient light fills the entire space, with no apparent source, which means that objects in the Astral Sea cast no shadows. The surface of the Astral Sea is covered in a thin layer of lavender-colored water that ranges from about 10-20 ft. deep; hence the name. Beneath the water is an impenetrable, unbreakable white substance known as "firmament" or "astral foundation." The atmosphere is breathable and the water drinkable to anyone who comes across it, regardless of their biological needs.   All of the other dimensions in the planar system "float" on the surface of the sea or in the air above. This includes very small dimensions, such as pocket planes and the lesser dimensions, as well as the larger planes. The planes may appear to be any number of different shapes and sizes, such as large spheres, floating islands, and even as ships or sailing vessels. When entering a plane from the Astral Sea, it is possible to appear at any location within that plane.   One of the most interesting and unique properties of the Astral Sea is that it is a dimension outside of time. Creatures do not age while within the Astral Sea (although they do require food and rest) and it is theoretically possible to navigate to any point in time in a particular plane. The infinitely long expanse of the tube holds an infinite number of instances of every given plane, from every possible point of time conceivable. Generally speaking, however, planes which are physically close to each other on the Astral Sea are also close to each other in time.   Many groups of people have attempted to use this timeless property to their advantage, but none are more famous or successful than the Gith. The Gith "live" almost exclusively within the Astral Sea on large sailing vessels, with which they navigate between the planes, either trading with, or most often pillaging, the inhabitants of those planes. Due to the nature of the Astral Sea, there are often hundreds of thousands of instances of a single Gith in the sea at any point in time -- and in fact, many Gith ships are entirely crewed by the same individual at many different points along their own timeline. The Gith use their psychic abilities with other instances of themselves to alleviate any confusion that might be caused by experiencing the same event more than once.