Nuclear physicist, Doctor Jim Al-Khalili, explains how the TARDIS works and looks into the theory of time traveling. | dG1fSDZJZVcxOWRtVmM
Category
🎥
Short filmTranscript
00:00Exterminate! Annihilate! Destroy!
00:03It's Doctor Who Night on BBC2.
00:30Doctor Who was always getting into trouble but the one thing he would always rely on to save him was this, the TARDIS.
00:42Now, it may look like an old-fashioned London police box to you, but as a physicist, what intrigues me is that it's a very sophisticated space-time machine.
01:01It looked like a London police box because of a clever ability common to all time machines built on Gallifrey.
01:07One of its functions is that it can change shape to blend perfectly with the surrounding environment.
01:12Unfortunately, this TARDIS wasn't working properly.
01:15So the chameleon circuit's stuck?
01:17Exactly.
01:18In Totter's Yard?
01:19Yeah, in our Totter's Yard. I mean, it was ages ago, it doesn't matter. She was in on Gallifrey for repair when I borrowed her.
01:24Scientifically, the idea of a chameleon circuit was of course way ahead of its time.
01:28Materials that could behave like a chameleon and change their shape and colour to fit in with their surroundings weren't even on the drawing board in the 1960s.
01:35It's only now, with the new science of nanotechnology, in which we hope to build things molecule by molecule, that it becomes even conceivable to speculate about it.
01:44There are two possibilities.
01:46The outside of the TARDIS could be made from synthetic polymer, which can expand up to five times its normal size.
01:53Its exact shape would be controlled by chemicals sent down tiny capillaries, just like blood vessels.
01:59The other theoretical possibility would be an amazing material dubbed utility fog.
02:05Here, rather than the shape of the TARDIS being built up atom by atom, tiny molecular robots would link together to form a solid mass that could change shape.
02:14In the case of the TARDIS, these robots would be controlled by an on-board computer or chameleon circuit.
02:19In theory, we should be able to do things like this.
02:24There.
02:26You have a door there.
02:28Yes, I suppose that's useful.
02:30Well, we've got to be able to get in and out.
02:32No, I mean being able to change like that.
02:34But the most magical property about the TARDIS is the difference between the outside and the inside.
02:41Which box is larger?
02:44That one.
02:50Now, which is larger?
02:53That one.
02:54But it looks smaller.
02:55Well, that's because it's further away.
02:57Exactly. If you could keep that exactly that distance away and have it here, the large one would fit inside the small one.
03:05That's silly.
03:09But there is another way of explaining how the inside of the TARDIS could be bigger than the outside.
03:14But there is another way of explaining how the inside of the TARDIS could be bigger than the outside.
03:18Theoretically, it's possible to join two distant points in space via a wormhole or tunnel that provides a shortcut through some higher dimension.
03:28The inside of the TARDIS isn't really inside a phone box at all, but in a different part of the galaxy altogether, and so could be as big as it likes.
03:37Wormholes can also explain how the TARDIS dematerialises and materialises in different places.
03:43Getting around the Doctor's Universe is a bit like getting around London. It takes ages to walk anywhere.
03:47But by using the underground, with its system of tunnels criss-crossing under the city, we can take shortcuts.
03:52It's just the same with wormholes.
03:55However, we would need a very weird type of material to make a wormhole. It'd have to have negative mass.
04:01Since it has no call to be here, the art lies in the fact that it is here.
04:06To make a TARDIS, we'd need the equivalent of the combined mass of all the planets in the solar system.
04:13Excellent.
04:17But who knows? Maybe the Time Lords on Gallifrey know something we don't.
04:32Time is marching on, but stay with BBC Two.
04:35The Daleks are coming! Don't move!
04:40Exterminate all human! Exterminate all...