Type: Interdimensional space
Environment: Alien
Usual Means of Access: Vibrational attunement
Dominant Lifeform: Unknown

Comments: Sub-space is a sidereal realm in which distance is compressed enormously. Through the expedient of warping into sub-space, faster-than-light travel can be achieved without directly violating principles of relativity. A journey through subspace can be extremely dangerous, since the slightest miscalculation could put the traveler into the heart of a star when he warps back into his own reality. Reed Richards' initial investigations into the mysteries of sub-space led him to the discovery of the Negative Zone. Sub-Space is also called Hyperspace.

First Appearance: FANTASTIC FOUR #37