In the end of season 2 of Doctor Who (2005), The Doctor needed enormous power to open the rift to the parallel universe to say goodbye to Rose. So, he burned up a star.

I don't know what burning a star means (as a star's already burning), but he also said something about orbiting a supernova, meaning he was drawing power from an exploding star (which can outshine 10 billion suns).

But why would he need that? Doesn't the TARDIS have a more efficient power source?

In the Journey to the Centre of the TARDIS episode, we saw the Eye of Harmony, the power source of TARDIS. It was created by suspending time around an exploding star in the act of becoming a black hole, harnessing the potential energy of a collapse that would never occur. From the episode, there were several exploding stars which were in permanent decaying states. Isn't this some kind of unlimited power source?

The collapse of star would never happen, but yet potential energy of collapse was the output. It looks to me a kind of time loop situation. At any given point of time outside Eye of Harmony, shouldn't Eye of Harmony give literally infinite energy as there'd be infinite number of collapse energy harness cycle by then?

Why exactly did The Doctor need to use an external, less-efficient power source in that case?

  • i assume that since the tardis power wasnt enough, and their are no more tardis/unable to created another tardis power source, having a star go supernova was the only way he had to get extra power. and it was getting into the parallel universe that cost so much power, (also i thought their was some problem were the tardis power source wouldnt allow him to do it, not that it didnt have the x amount of power it litterally couldnt)
    – Himarm
    Oct 21, 2014 at 13:56
  • I think you've answered your own question. He caused a sun to go supernova to use as a power source.
    – Valorum
    Oct 21, 2014 at 14:01
  • 9
    I think the out-of-universe explanation, that they had to make it clear Rose was nigh-unreachable and that an actual reunion was not possible, probably trumps any in-universe explanation.
    – gowenfawr
    Oct 21, 2014 at 14:08
  • "literally infinite energy" made my intellect hurt -.- Oct 24, 2014 at 12:59
  • @Lightness Haha.. Yeah, that should hurt coz it's Wibbly-Wobbly stuff. Don't forget, that thing almost destroyed the universe (which is infinite) before The Doctor rebooted the universe.
    – user931
    Oct 24, 2014 at 13:46

1 Answer 1


As you pointed out, the energy output of the star at the center of the Eye of Harmony is vast, but finite. And with Gallifrey (as far as he knew at the time) dead and gone, once that power is gone, there's no way to get another. The Doctor has been able to use rift energy from time to time to recharge some of the power systems, but we don't know if those are linked to the Eye (think BTTF -- Mr. Fusion powered the time circuits, but the car still needed gasoline to run). If that's the case, then using the power from the Eye for anything other than time travel means one less trip the Doctor gets to make.

It's also worth pointing out that he wasn't using the power to open the rift. The rift was in the process of closing, and he was using the power to boost a signal through the last little pinhole before it sealed itself off completely. That being the case, draining power from the Eye might have been overkill.

So, it might have just been the Doctor being conservative with a limited fuel supply. Why burn off energy from the Eye when siphoning off a supernova would work just as well?

  • Plus this is his last chance to impress this particular girl. Dec 8, 2015 at 10:02

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