The astral void extends to infinity. It shimmers, evoking infinite possibilities and subtle beauty. Land on one of these, and perhaps the adventurers will have strange dreams. Either way, visitors find themselves in the astral standing by a silvery pool, looking into a reflection of the familiar world. In moments, they are whisked away, perhaps hurtling among images of stars and galaxies beyond numbers.
Time is meaningless here, and all journeys are extremely rapid.
The astral is the dimension of undifferentiated ideas that sustains the alignment planes, just as the elemental planes sustain the world of matter. Here is a possible encounter table for the astral, but it seems likely that one would tend to meet those of similar interests and attitudes. Perhaps the astral would require that creatures encountered have something in common with, or some interest in, the travellers. In a dimension which underpins all higher purposes, things should happen for a reason. Since the astral is the dimension in which people's interests shape their experiences, then encountered creatures must surely appear in the midst of the party.