The Astral Dimension, much like the Mirror Dimension, coexists alongside the Material Plane. However, to access it, one must successfully be separated from their physical form, existing in a state of pure energy. Time in the Astral Dimension is slowed down to a crawl, to the point that Doctor Strange was able to leave his body, speak with the Ancient One, and return in the time it took his body to fall to the floor.
While in the Astral Dimension, sorcerers can still cross over to other dimensions, as Strange was able to seemingly cross through the Mirror Dimension to assist Christine Palmer with his surgery. Sorcerers are also able to peer into the Astral Dimension without leaving their bodies, as both the Ancient One and Doctor Strange were able to see each other's astral bodies while in the Material Plane. While speaking to Christine Palmer in his astral form, Strange was also able to see Lucian arrive. The Ancient One was able to project and return Strange's astral form to his body, suggesting that powerful sorcerers can control the Astral Dimension to some extent other than astral projecting.
Sorcerers have limited effect on the Material Plane while in the Astral Dimension, as during their Duel on the Astral Plane, Lucian and Doctor Strange were able to cause equipment to move around and lights to burst. Due to the astral form being energy, if a sorcerer's body is exposed to high amounts of energy, such as electricity, their astral form becomes charged to the point that Strange was able to kill Lucian by overloading his astral form after Christine use a defibrillator on him.
One can simultaneously rest their bodies and perform other tasks using the Astral Dimension, as Doctor Strange was shown to be sleeping while studying a book in his astral form. Also, like the Mirror Dimension, the Astral Dimension is accessible without the use of the Sling Ring, as it occupies the same space as the real world while still being imperceptible.
For Black Panthers, after consuming the Heart-Shaped Herb, they are put into a slumber and buried, reawakening in the Astral Dimension by rising from the earth. The experience is shown to be extremely jarring, as both T'Challa and Erik Killmonger awoke from their visit visibly shaken and disoriented.
