The Primary Universe is fraught with great peril. War, plague, famine and natural disasters are common :: The Fourth Dimension of Time is a stable construct, though it is not impenetrable :: Incidents when the fabric of the fourth dimension becomes corrupted are incredibly rare... The linear paradigm of Time as a single "line" is a theory constantly in need of correction :: Potential energy may build in the local collective unconscious, leading to wave interference from a Parallel Universe... If a Tangent Universe occurs, it will be highly unstable, sustaining itself for no longer than several weeks :: Eventually it will collapse inward upon itself, forming a Black Hole within the Primary Universe capable of destroying all existence... The only indication such an event will occur, by definition, will appear at some time in the past... The past is more malleable than it appears, when seen through the present moment, from the future...