The time differential describes a state of being between multiple points in a single timeline coming into contact with one another. When a human or object met itself from a different point on its own timeline, the Blinovitch Limitation Effect meant physical contact between the two versions would short out the time differential between them. This could result in dangerous effects such as a large energy discharge or damage to time itself. (TV: Mawdryn Undead, Father's Day, The Big Bang)