The TARDIS is one of the few fictional objects that could contain themselves. Firstly, because "it's bigger on the inside" but secondly because the TARDIS has some means of sustaining paradoxes (which have their bounds, but it is capable to allow some paradoxes if you don't overdo it).

So if you had some sort of Portal technology (like in the game of the same name) which allowed you to create portals at will, you could shoot one portal inside the TARDIS and the other outside and fly through the outer Portal with the police-box-shaped TARDIS, assuming the portals were big enough.

If you remove the portals, where would the TARDIS be? Would this even work?
I realise canonic answers are probably hard to give, so I'm fine with some well backed-up hypotheses.

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    @Ryan: Nah, video feedback-loop is kindergarten compared to this. This is wibbly-wobbly. – bitmask Sep 24 '12 at 13:03
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    @SaintWacko Does the TARDIS interior ever actually move? – Iszi Sep 24 '12 at 13:05
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    Note that the TARDIS has canonically been inside itself, in the mini-episodes Space and Time. – Daniel Roseman Sep 24 '12 at 14:07
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    Just don't put a portable hole on the side of the TARDIS. The TARDIS is effectively a bag of holding with a swimming pool, right? – AncientSwordRage Sep 24 '12 at 15:46
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    Why is this opinion based, if it happened (it did, according to accepted answer)? – TGar Jun 3 '17 at 10:37

As @Daniel Roseman points out in his comments, this has actually happened in the Children of Need special mini-episodes Space and Time (contained on a Doctor Who DVD and confirmed to be "canon" by Moffet). In this episode, an emergency landing causes the TARDIS to materialize in the "nearest safe location", which happens to be inside the control room of the TARDIS.

Several interesting things happen once this takes place:

  • The doors to the TARDIS form a closed spatial loop. Anyone entering the doors of the "inner TARDIS" come through the doors of the "outer TARDIS" and vice versa. There does not appear to be any way to actually leave the TARDIS, nor for anything that's not already inside the TARDIS to get inside of it.

  • The "outer" TARDIS somehow drifts away from the inner one temporally: entering the "inner" TARDIS results in you coming through the "outer" doors several seconds earlier. Note that this does not happen immediately: at first The Doctor is able to move instantly between the doors, but seconds later Amy comes in from the future.

  • Eventually, The Doctor is able to reverse the effect through a "temporal implosion" in which both TARDISen dematerialize and everything goes "back to normal".

From this, given your portal scenario, we can draw a number of conclusion:

  1. It's perfectly legal for the TARDIS to be completely inside itself, and whatever temporospatial technology runs the TARDIS can readily adapt.

  2. Once the TARDIS becomes self-contained, it really is fully contained inside of itself. There is no path through space that starts or ends in the TARDIS except those paths that do both.

  3. There is still only one TARDIS, somehow recursively contained within itself. Note that Amy enters the "inner" TARDIS twice, while Rory only does so once, and yet both end up together in the "final" TARDIS.

  4. There is some form of temporal drifting effect between the inner and outer edges of the doors. Over time, the "external shell" (e.g. the outside of the doors) move ahead of the "internal shell", causing someone entering the contained TARDIS to come through the other set of doors in the past.

  5. Once self-contained, it is possible to remove the TARDIS from itself; this causes the TARDIS to dematerialize and reappear in "normal" space just like any normal take-off.

  6. Amy, a miniskirt, and a glass floor could potentially end the universe.

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    A miniskit, hmm? – rsegal Sep 24 '12 at 18:23
  • I've never seen the old episodes. But if this is an accurate description, then they handled it both in an interesting and plausible way. – John O Sep 24 '12 at 21:27
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    TARDISen? Is that the proper pluralization? – SaintWacko Sep 25 '12 at 3:20
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    No I'm pretty sure its really TARDISes. – KutuluMike Sep 25 '12 at 16:30
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    +1 | A bloody brilliant answer. Well done! – Thaddeus Howze Jun 23 '13 at 6:40

This is mostly a topology question. For simpler examples, you might take a look at a Moebius strip or a Klein bottle.

It's difficult to explain, our brain circuitry has evolved to understand mundane 3d space and doesn't deal well with such things. But the big blue police box would just be sitting there in the control room, with the exit door twisting back in on itself to open back up inside. It seems like this shouldn't be possible (and it probably isn't, we are talking about fiction after all), but if one region of space doesn't need to connect to the adjacent region of space, then there is nothing that should prevent such a thing.

Presumably, this would mean that the TARDIS is still in whatever time/space that it was before you put the exit/police-box inside of it (and, that it can travel to other locations and times even in this state). So if he had piloted it to London in 1968, it would still be there, though to the people of London it would be invisible.

It would clearly lack an entrance for the people of London to enter it. It may or may not lack an exit for the Doctor and his companions to leave into London. On that last one, I get the distinct impression that the insides of the TARDIS are vast, maybe a few square kilometers of livable space, so who can say whether there are other exits? If there are, and one was used, I would expect that they would have a much more spectacular appearance from the perspective of those outside. They'd just see a borderless portal open in the middle of the air.

If such is correct, then that would be the solution to fixing such a problem... they'd pick up the police box and cart it out through another door.

  • I'd say this sounds like the most likely case. I hadn't thought of it in terms of a Klein bottle, but it makes sense. – SaintWacko Sep 24 '12 at 13:17
  • How do you figure the box would still be in London? Where exactly? Just before it enters the London-portal it would be there, but just a bit later, when it exits through the inside-portal, if it is still in London, I put to you the question: Where? Note that the inside-portal travels with the blue box through the London-portal and comes out of itself. – bitmask Sep 25 '12 at 0:54
  • I did not say the box would be in London. Only that the TARDIS would be. The box is just the facade that's visible to those in the real world. The TARDIS is the entire machine. Where? Wherever it was piloted to. – John O Sep 25 '12 at 1:27

Am I the only one who thought "well, it is bigger on the inside" first off? :P I mean, think of it like this. The TARDIS stands for TIME AND RELATIVE DIMENSION IN SPACE... key word, relative. The inside of the TARDIS isn't compressed inside the outside, more like the doorway is a gateway to another dimension (although not exactly, more like a gateway to another part of space, hence the "relative" part). All this means is when the Doctor uses the control room to the TARDIS, it isn't like flying a ship, but more like guiding a missile from a remote location. It wouldn't be hard to put a missile in a control room. The only problem for the human brain is thinking about two parts of one entity being simultaneously occupying the same space.

Now, that being said... the way the TARDIS is set up is completely different from the gateway theory because if something happens to the outside, it affects the inside and vice versa. This can be explained by the latter part of "two entities occupying the same space" cause and effect. If two things are at the same place, and one is affected by something (explosion, attack, etc.) then the other would have to be affected unless it is out of phase, which no part of the TARDIS is most of the time. It is plausible that, if one part was out of phase with the other, that one could be destroyed and leave the other. I think this is what they were trying to accomplish in the episode with the Lever the doctor had to pull. It was the lever to "unsync" the two parts from the same phase of existence.

I think I got off topic a little (or a lot lol) but it was fun writing it :)


Well, the TARDIS is not really bigger on the inside when you get into technicalities. The outer shell is just a police box, and it contains a gap to a different dimension containing the inside, and the gap goes straight to the doors of the inside. So if you shot one portal outside of the TARDIS and one inside, the portal would go through two dimensions. Assuming the portal gun is capable of intradimensional quantum tunneling when the outside of the TARDIS went through the portal it would shift to the dimension containing the inside of the TARDIS. When that happened it would either destroy the portal connecting the two dimensions because both sides of the portal are in the same dimension, making it so the outside of the TARDIS was empty and the outside of the TARDIS went straight into the dimension where it actually was making it so if you went out instead of seeing a police box you would see the massive TARDIS inside, or the other possibility is that the portal would be able to adapt itself so that instead of going through dimensions it went through space, making it so attempting to exiting the TARDIS would make you go out of the police box that is inside of the TARDIS interior, although if this was the case it would be possible to simply deactivate the portal making it so that entering the police box would be a normal police box, and exiting the interior would bring straight to whatever dimension the interior exists in but instead of seeing a police box from the outside you would see, well, I already explained that.

Hope the amashing wizdom that I juiced from my brain helped!

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