Blinovitch Limitation Effect

The Blinovitch Limitation Effect was a natural function of the universe that described the effects of approaching and/or making physical or causal contact with a future or past version of yourself, an action that was also referenced as "crossing your own timeline".

The effect was named after Aaron Blinovitch who, in 1928, formulated the Blinovitch theory in the reading room of the British Museum. (PROSE: The Ghosts of N-Space)

The Ninth Doctor said that prior to the time-locked destruction of the Time Lords in the Last Great Time War, his people could have prevented or mitigated the effects of a paradox. (TV: Father's Day) The Blinovitch Limitation Effect was modified by the Time Lords and their temporal technology on Gallifrey, although crossing one's own time stream required enormous amounts of energy and broke the First Law of Time. (TV: The Three Doctors)

The Doctor mentioned the effect when explaining why he or another cannot simply go back in time to take another try when a plan fails. (TV: Day of the Daleks) The Time Lords and other time-aware and time-active groups could, with technological assistance, suppress the effect. The Time Lords expended energy to suppress these effects in TV: The Three Doctors, and the Eleventh Doctor used the sonic screwdriver to do so in PROSE: Touched by an Angel, and the Doctor's TARDIS did so herself when reconfigured into a multi-dimensional city in PROSE: Cat's Cradle: Time's Crucible.

If an item or person crossed their own timeline and the past and future versions came near each other or physically touched each other, energy would be released. The Fifth Doctor called this "shorting out the time differential." In some cases, this energy caused memories to be transferred from the past to the future person, who then suffered amnesia until both versions of the person have experienced the event. (TV: Mawdryn Undead) The energy released from contact between two versions of a person was usually enough to overload any surrounding technology. Just by being in the same room, the two versions created a Blinovitch Limitation field, a crackling blue energy resembling lightning. (PROSE: Touched by an Angel) The Doctor has been able to purposefully dampen the effect through the use of a sonic screwdriver. (PROSE: Touched by an Angel)

Several other concepts were related to the Blinovitch Limitation Effect and its corollaries, althought it was unclear which are specifically due to the effect and which are effects of other theoretical temporal concepts driven by the natural law. When a person used time travel to attempt to change their own existing timeline, the deviation could create a time loop, which was a type of paradox. (TV: Day of the Daleks)

In his seventh and eighth incarnations, the Doctor claimed the title Defender of the Laws of Time. (TV: Remembrance of the Daleks, PROSE: Vampire Science) After the Last Time War, the Doctor occasionally crossed his own timeline or crossed into established events, after he had identified evidence or testimony that someone from the future had crossed into his present or past. For example, the Tenth Doctor went back to meet with Martha Jones on her way to work to prove he could time-travel, after she had told him she'd seen him earlier. (TV: Smith and Jones)

On occasions before and after the destruction of the Time Lords, the Doctor physically interacted with different incarnations of himself or with another version the same incarnation without appearing to trigger the effect. In several cases, Time Lord technology was available to dampen the effect. In others, the previous incarnations temporarily aged as a result of the time differential. (TV: The Three Doctors, The Five Doctors, The Two Doctors, Time Crash, and COMIC: The Collector) At one time, the Eleventh Doctor was in a universe that was fading away as a consequence of the explosion of the Doctor's TARDIS. A future version of himself appeared, grasped him, and whispered something. This did not trigger an energy discharge. His sonic screwdriver, however, did spark when touched to another version of itself. The Doctor took this as a confirmation that it is the same screwdriver, although he didn't name the effect at this time. (TV: The Big Bang)

After she created a temporal paradox by saving her father from death, he gave Rose Tyler the baby to adult Rose, well bundled, to hold. This produced enough of a temporal paradox to allow a reaper to enter the church in which they were sheltering. (TV: Father's Day) Two versions of Kazran Sardick touched each other without triggering the effect. (TV: A Christmas Carol) Similarly, Amy Pond as an adult and child touched on at least two occasions. (TV: The Big Bang, TV: Good Night) Two incarnations of either adult Amy or of her identical Ganger, approximately one minute older/younger than the other, touched each other flirtingly. (TV: Time)