As much as I love Douglas Adams and his work (hint: hugely), I can't let this one slide: crushing planets into tiny, extremely dense balls of rock to harvest psychic energy and create a "time-dam" out of an old woman in suspended animation is a concept so riddled with errors that not even Tom Baker's pleasingly eccentric scarf can prevent some physics-induced rage.
The idea that matter contains energy is true, as Einstein's famous equation E=mc2 shows, but for elements lighter than iron this energy is only released through nuclear fusion reactions and is in no way affiliated with Derek Acorah. The shrunken planets could ignite and form a star if a huge amount of mass was condensed, but that powerful source of energy would come at a cost of a formidable gravitational pull and the incineration of any nearby societies. Highly impractical and hugely ridiculous, Queen Xanxia's plan still remains the only possible explanation for the extortionate power demands Apple satisfies to keep its stores retina-searingly bright on both sides of the Atlantic on a day-to-day basis.
Remember how I told you earlier that there are billions and billions of electrons within your body? As per usual, physics loves to make things just that little bit more complicated by dropping a brand new bombshell on anyone listening: there may only be one electron in the entire universe.
According to Feynman diagrams, an electron is a subatomic particle with a negative charge when it is travelling forward through time. Its opposite number is the positron - these have the same mass and magnitude of charge as electrons but this time the charge is positive and the particle would be traveling backwards through time. In the one-electron universe hypothesis the particle travels to wherever the collapse of a wavefunction is needed, giving the impression that there are many electrons when there is only one. Think the Double Team move from Pokémon, but less irritating.
Theoretically, electrons also have the ability to be in two places at once thanks to interference which can happen when one of them passes through two very narrow slits, so it could be entirely possible for the TARDIS to travel almost instantaneously provided there are bizarre mechanisms available to harness both phenomena on a large scale.