Astral Plane

The Astral plane (sometimes Astral Plane) was one of the planes of existence in various models of cosmology. "It is the space between everything. It is the road that goes everywhere. It is where you are when you aren't anywhere else."

- Manual of the Planes

Astral Plane in the Great Wheel Model
In 1st and 2nd edition D&D, as explained by the Great Wheel cosmology model, the Astral plane connected the Prime Material Planes to the first layers of the Outer planes. The Astral could be reached from almost any point in a Prime Material plane or first layer of any Outer plane by spell, psionic ability, or device. It was described as a barren place of other-dimensional nothingness extending in all directions. What little solid substance that floated in the bright, gray void was typically chunks of matter broken off from their original plane. The Astral had no gravity but objects did retain their mass so you could throw small items or push off from large objects to move in the weightless environment. Time in the Astral flowed at the same rate on a Prime Material plane but the effects of time were slowed almost to a stop&mdash;a thousand years in the Astral plane felt like only a day to the traveler.

Entering the Astral plane could be accomplished in one of two ways: projecting your astral form into the plane, or by physically entering the plane. Astral projection was the safest way to travel but still involved risk because you left your physical body behind on your plane of origin. Your astral body would be accompanied by the astral forms of any items and clothing that were magical or radiated a magic aura. While projecting, your astral self was connected to your physical body by a silver cord that stretched out behind you for about ten feet (three meters) and then became invisible and intangible. Very few things could sever this silver cord: a powerful psychic wind, a githyanki silver sword, or the will of gods. The physical body left behind appeared alive but did not require food, water, or air and did not age. It could be moved and was vulnerable to damage and death. If your body was slain, you died some minutes later. If your astral self was slain, you returned to your physical body in a coma. Physically entering the Astral plane required a spell such as plane shift and brought the traveler wholly into the Astral with no silver cord to anchor her to her plane of origin.

Upon entering the Astral plane you saw a silvery color pool nearby&mdash;a portal to the Prime Material plane you came from. Astral projecting travelers saw their silver cord leading back to this pool. Color pools appeared as two-dimensional circles about 10-60 feet (3 to 18 meters) in diameter and only visible from one side unless you had some way to detect invisible objects. Pools of different colors were portals to the different Outer planes. Each Outer plane had its own unique color but your home portal was always a metallic silver, rippling like mercury in a pan. Color pools could be used to view the destination plane before stepping through by mentally concentrating on the nearby pool until it became transparent. A viewer could also move (with some limitations) the portal's viewpoint by concentration. Astral projecting travelers formed a new physical body (with silver cord attached) when they stepped through a color pool to their destination plane. The new body was formed out of local materials so the greater the similarity between your home plane and your destination, the more your new body looked like your original one.

Astral Plane in the World Tree Model
In the 3.5 edition of D&D, the Astral plane was described as a shapeless cloud that surrounded all the other planes (including the Inner planes which were not accessible via the Astral in the Great Wheel model). The Forgotten Realms World Tree cosmology model modified the Astral plane to be tree-shaped, touching nearly all planes, and overlapping the World Tree as well. The ramification of this is that travel between planes was not easily accomplished without going through the "trunk" of the tree (i.e., the Material plane). Direct connections between separate dominions of the gods was only possible by cooperation between the deities in question.

The Astral Plane had the following traits in the World Tree cosmology model:
 * Subjective Directional Gravity: a traveler picked a "down" direction and "fell" in the direction until a new direction was chosen.
 * Timeless: the effects of time were suspended until the traveler exited the Astral Plane, whereupon the effects retroactively occurred.
 * Mildly Neutral-Aligned: no circumstance penalties.
 * Enhanced Magic: Spells and spell-like abilities could be used as if augmented by the Quicken Spell feat.

Color pools still existed in this model, but an Astral traveler had to choose the destination plane before setting out and would only encounter pools that lead to the chosen plane. To change destinations, the traveler had to reenter the Material plane and then begin the journey anew.

Toril's Material plane actually linked to several other Astral planes, each of which connected Toril to the outer-planer homes of a different set of deities. They are based on the geographical areas of control held by the different pantheons. As such, there is an astral plane for the Maztican and Zakharan pantheons (even though many of the Zakharan deities may reside on the Material Plane). The Kara-Turan faiths are not connected to their own astral plane, as instead their deities connect to the Spirit World. Very little is known in Faerûn about these other astral planes but it is theorized that Ao supervises them just as he adjudicates the conflicts between the pantheons.

Astral Plane in the World Axis Model
In 4th edition Forgotten Realms lore, the Spellplague set the dominions adrift&mdash;they were no longer linked to a tree-shaped Astral plane but floated aimlessly in the Astral Sea.