FANDOM

Ask a question in the box below, or search using the box above.

As you enter your question, our massive, TARDIS-sized computers will search out other similar questions. So be sure to check the list that pops up before asking your question. Once you've decided that your question has not been asked before, push the not-so-threatening blue button below.

If you want to ask questions needing speculation or people's opinions, please do it in our Watercooler forum, not here. The main Q&A space is for questions with definitive factual answers. Thanks!

To avoid spoilers in the main Q&A section, please do to not post information about stories that have not been released in the UK, or ask for information about stories that have not yet aired there.

He can cross his own timestream (travel to a time & place he has already visited), although he rarely does. Crossing one's own timestream is not physically impossible but it's forbidden by Time Lord law (the First Law of Time), as it runs the risk of creating serious paradoxes. However, the first time we saw the Doctor cross his own timestream (in "The Three Doctors"), it was arranged by the Time Lords themselves, because they were facing a threat that was more dangerous than the risks associated with breaking the First Law of Time.

The universe is so large -- in both space & time -- that there's only a tiny chance of the Doctor (or anyone else) crossing his own timestream by accident. When it happens, it's usually because someone or something has intentionally caused it.

  • In "The Three Doctors", the Time Lords did so on the orders of their then Lord President.
  • In "The Five Doctors", Borusa (who was Lord President at that time) used the Time Scoop to bring it about for his own illegal purposes.
  • In "Father's Day", against his better judgement, the Ninth Doctor deliberately crossed his own timestream (& allowed Rose to cross hers) as a favour to Rose. That incident showed some of the dangers of doing such a thing.
  • In "The Big Bang", the Eleventh Doctor deliberately crossed his own timestream in order to give the Auton duplicate of Rory Williams the sonic screwdriver & instructions on how to let the Doctor out of the Pandorica. (That also created a paradox but it was a sustainable one, unlike the paradox in "Father's Day".)
  • In "The Day of the Doctor", "something" allowed the War Doctor, the Tenth Doctor & the Eleventh Doctor -- &, eventually, all the first 13 incarnations of the Doctor -- to get together to save Gallifrey. That "something" also allowed these incarnations (other than the War Doctor, who was already there) to pass through the time lock on the Time War. It was implied, but has never been explicitly confirmed, that this "something" was the Moment.

See alsoEdit