The Supernal is a realm that imbues and connects the Real World and the Spirit World. It is the subject of the Prime Arcana, and is whence the Ley lines, Hallows and Mana flow into the the worlds. It is not a world on its own accord.
The Awakened understand it as something that was created while the earth was young, by unknown powers. Those powers do not affect the use of the Supernal by the Awakened, but might be connected with the Paradox events.