In the 50th Anniversary episode:

the Doctor(s) decide that instead of destroying Gallifrey, they should freeze it. Now for some reason, this involved ALL the Doctor's incarnations to perform some calculations that would take hundreds of years. However, why did this involve the Doctors 1-8 (I can understand why Capaldi came in as he is the future Doctor so maybe he comes back to help out or something)?


the idea of Doctors 1-8 performing these calculations that'll freeze the TARDIS may be plausible as they may have been doing so without realizing, but then why did all of the Tardises appear at the point where the 3 doctors in the main episode freeze Gallifrey. Shouldn't the Doctors 1-8 have had no involvement at all as they are in the past (relative to Gallifrey’s freezing)?

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    I'm hoping the phrasing of my question wasn't discombobulated. Can at least one person comment and say they understood my question so I don't feel like I'm talking to myself. – 83457 Nov 23 '13 at 22:37
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    Sorry, I have to say it... It's timey-wimey. – Greenstone Walker Nov 25 '13 at 3:42

11 Answers 11


I think it was just for the coolness factor- 13 doctors fighting to save their planet.

In fact, even the three doctors shouldn't have been able to meet. As David Tenannt says, the Time War is locked, and they should not have been able to visit it. But it seems Billie Piper has just waved her hands and made the Time Lock vanish, and pull the doctors together.

At the end of the episode, there is more hand waving, and we are told that due to some "time sync" (what?), they will all forget their memories.

So to answer your question: The Interface aka Billie Piper aka Rose aka Bad Wolf called all the Doctors together, across time, so they could save Gallifrey. Because she is Billie Piper, and she can do stuff like that.

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    That wasn't Rose Tyler, it was The Moment using that form to communicate with The Doctor. – user1027 Nov 23 '13 at 23:43
  • As @Keen said, she was the interface to the small (pandorica-like) Bomb. Best interface ever. – bitmask Nov 24 '13 at 9:20
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    Yes, I know she wasn't Rose. I was just being tongue-in-cheek – Shantnu Tiwari Nov 24 '13 at 9:29
  • The interface pulled them all in before the time locks was put in place, didn't she? Or this an alternate past where there was no time lock, and now there is? – AncientSwordRage Nov 24 '13 at 18:11
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    The Doctor has always lost his memory of meeting himself in the other specials, as far as I know. – Izkata Nov 25 '13 at 0:57

The Doctor (11th or beyond) will go back in time to meet every incarnation and give them the information. Then they each delete their memories selectively so that their timelines aren't contaminated by the knowledge. Alternatively, he goes back to the first incarnation, gives him the information, and every incarnation gets it from the TARDIS before forgetting it again. They each remember it only for the duration of their part of the intervention. The TARDIS has done the calculations for centuries without the Doctors being aware of it most of the time. The time lock could have been a false memory or selectively and temporarily lifted by The Moment.


OK the character played by Billie Piper was not ACTUALLY Rose.. it was the conscience of "The Moment" (which was the uber-weapon that John Hurt's doctor stole from the weapons archive of the time lords in order to end the Time War). It simply took the Bad Wolf form in order to be familiar to The Doctor, but managed to get confused over the difference between past and future. It was the weapon's conscience that pulled the "future" Doctors (Smith and Tennant) into the "present" (from the perspective of the Time War) in order to let Hurt's Doctor decide if he was going to blow everything up or not.

Why did all thirteen doctors appear? As the Galifreyan timelords mentioned it was an incredibly complex series of calculations that would take hundreds of years. One of the Doctors (Tennant I think) replied that he'd been "working on it for a very long time" at which time the image of Hartnell's Doctor appeared (followed by all the others), implying that The Doctor had been working on the problem of how to hide Galifrey for ALL of his incarnations from Hartnell onwards - in much the same way that they used the time differences in the generations to solve the calculations for destroying the door in the Tower of London.

It would make some sort of sense for the Hurt and Tennant Doctors to not remember as they'd been pulled out of their time stream, and returning them to their time stream would allow time to "heal itself"... it also HAD to be done that way or Tennant's Doctor would not have had a reason to be so beat up over having killed all his race... coz he actually hadn't.


Well, the calculations took hundreds of years, so they'd need that much computer time (from the TARDIS). Since they can obviously visit themselves in the past (there are rules against that, which they are already breaking, but not physical impediments), they (or one of them) must have gone back to at least the first Doctor and informed him about the plan.


Early on in the episode, the Moment is shown to be capable of opening time fissures that lead to different points in the Doctor's history. It was the force that brought Smith's, Tennant's, and Hurt's Doctors together and also allowed Smith and Tennant's Doctors passage into the Time War. It is very likely that it was also the vehicle by which the earlier Doctors were brought forward into the Time War in order to save Gallifrey since it was actively helping the main three Doctors. There wouldn't even be any risk of showing the earlier Doctors their own future because, like Hurt and Tennat's Doctors, they would have been out of sync with their own timestreams and would have forgotten all about helping to save Gallifrey once they re-synchronized.


I too was very skeptical about why the doctor needed to involve all of his past regenerations in order to save Gallifrey.

When the 11th doctor decides change his own past and save his home planet, the dialogue is as followed:

The War Doctor: "There's still a billion billion Daleks up there attacking us."

11th Doctor: "Yes, there is! There is!"

10th Doctor: "But there's something those billion billion Daleks don't know."

11th Doctor: "'Cause if they did they'd probably send for reinforcements."

Clara: "What? What don't they know? "

11th Doctor: "This time there's three of us."

He gathers all of his past regenerations in an effort to freeze Gallifrey as seen in the following moment:

General: "It's delusional! The—the calculations alone would take... hundreds of years!"

11th Doctor: "Oh, hundreds and hun—"

10th Doctor: "—dreds, but don't worry. I started a very long time ago."

It doesn't make any sense that this calculation can only be running for the duration of the doctor's life. Couldn't the 11 doctor go back to say the Jurassic Period, burry a calculation in the ground, and then travel to the future and get the result?

And let's say the doctor needed the TARDIS at different points around Gallifrey in order to do the freeze, it still doesn't make sense why he couldn't have just kept revisiting the same point himself, and have a ton of Matt Smith doctors solving the problem.

After giving it some thought however, here is the only valid explanation I can come up with(other than the obvious: "It was cool to have all the doctors"):

The doctor cared about having all of his faces involved in the saving of his home planet. He wants them all to be "The Doctor".

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    I believe the calculations required the TARDIS. – Django Reinhardt Dec 9 '13 at 14:44

Well let's actually look at an example from the episode with the sonic screwdriver. The Moment/Bad Wolf reminds the War Doctor that the Sonic Screwdriver is the same device with a new casing, so when he starts the calculations that would destroy the door, 11's Screwdriver has the calculations finished, however neither 10 or 11 seem to remember that these calculations have been going on for all this time. At the end of the episode, both War Doctor and 10 mention that THEY won't remember the events, implying that 11 will. And when the Curator of the museum which insinuated that he MAY be a future incarnation of the Doctor he went out of his way to be vague as to not confirm that he is.

There are other examples that touch base on this phenomenon. There is a short where the 10th Doctor's TARDIS accidentally merges with the 5th's. 10 does a complicated trick with the TARDIS that is able to separate the two. When 5 asks how he knew how to do that 10 replies that he remembers being 5 and seeing himself (10) do what he just did. In A Christmas Carol, 11 goes back in time to when Kazran was a child and the adult Kazran memories change as things are happening in his past, but he retains some of his other memories to a point that he knows the Doctor has tampered with his past.

So from these examples, I think that the Doctor could potentially tamper with his own past as much as he wants and his past incarnations would not remember it until the moment when they are the latest incarnation involved in the situation. Therefore, 11 communicated with all of his past selves telling them the exact situation and telling them to go to the specific space time coordinates to save his/their home knowing that as soon as they go back to their individual business they wouldn't remember what happened until they were him. As for Capaldi, I can only assume the 12th Doctor will have further calculations to do that will involve him going back to this instance, but also being very vague so his past self (11) will not forget what happened. There is likely rules against doing this because it would be a tremendous strain on the mind of the person furthest along in their personal timeline.

In short, wibbly wobbly timey wimey stuff.


The weird tears in spacetime, those small upside down tornado-thingeys, they made this possible, the doctor could never go back in time to the time war. But the tear in reality made by the moment makes it possible anyway! And the doctors before the time war can go there because they are not going back in time, but forward. It all makes sense.


Complete speculation: The Doctor placed a subliminal message in the Untempered Schism. When he looked into it as a boy the message was implanted into his brain so that all of his adult life he was working on the problem unconsciously.


All the Doctors must have known of the Timewar- not perhaps its details, but certainly in their travels from one end of space-time to the other they must have noticed why a huge part of it was locked up and tried to get through, repeatedly, trying to work out why it was a locked region of space time and what it meant. And assuming that it probably wasn't good , but that they'd become involved at some point in their timeline as a result of natural causality eventually anyway.

As soon as the Moment allowed the subsequent doctors entry to the otherwise locked up region of space-time all the others retrospectively got access too- once it was no longer barred to them it never had been barred to them! Normal causality resumes:

#1 enters the fray and evaluates the situation- realises Gallifrey can be saved by a particularly difficult and long running calculation - Checks to see if Deep Thought is free, but it is already booked in at another gig in another dimension, and so starts the calculation. #'s 2 to 12 (inc WD) check their instruments and find the calculation has already been running .... #13 arrives, 9 centuries* after #1 and 50 feet to the left, announces calculation complete and sends out the result to himself.

Gallifrey is saved. Couldn't be simpler if you think about it.

*Or 7 centuries after. or 18. Or pretty much any other number you like. Sort of depends on which of the doctors various guesses as to his own age is the most accurate. I suppose after centuries of traipsing around space-time in a time machine, time and causality themselves probably just become optional extras...


If you think about it, it wasn't the Doctor's plan it was The Moment's plan. She was the one who gave it to the War Doctor to handle the door. She planted the plan into all three of them.

She is also the one who can see throughout the Doctor's whole timeline (it’s where it got Lone Wolf to begin with). The Moment was also able to get the Doctors together in the first place. It could go pick up the full set, so to speak

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