This is a collection of things I find myself answering quite often in Doctor Who forums etc.
Since It's things I want to say, but I don't want to write the same things over and over again, here you go.

These are not all my ideas. Some of them are just ideas worth repeating. If there's any idea that originated from one specific person I can credit I'll credit them but most of them are either mine or just floating around.

This is not canon! These are just things I, or others, thought up. It could all turn out to be false.

Spoiler warning.. For whatever's been broadcast anywhere, I guess.

- ailaG (Google me to contact)

• Fall of the eleventh

I don't think we should take that phrase at face value – that's what they WANT us to. The fall of the 11th may mean autumn (fall) 2011. Or it may refer to something we haven't come across yet.

As I mentioned in another item on this page, we don't even know if Matt Smith's Doctor IS the 11th. That number could be higher than we think.


• First question - why is that the question? (Spoilers S06E13)

This isn't mine at all, I took the entire idea off of another commenter I can't recall the name of. Sorry..

"Doctor Who?" is the first question because in 6x13 River sent a signal outside their collapsing bubble universe saying: "The Doctor is dying. Please, please help." That signal must've reached some kind of ancient civilisation that the Doctor hasn't yet visited and yet they could decipher it, and inevitably ask.. Doctor who?


• Numbering - 10th, 11th etc…

I usually don't name Doctors by the number (9 = Eccleston, 10 = Tennant, 11 = Smith) because:

  1. We can't be sure that during the Time War (between McGann and Eccleston) the Doctor died and regenerated *exactly* one time. He DID fight on the front.
  2. I'm not sure that we know whether he ever regenerated before Hartnell. I haven't seen these episodes yet.
  3. In Journey's End he does regenerate, so Smith is technically 12?

Keep in mind that the 12 regeneration limit was (AFAIK) enforced by Time Lord, not given by nature. A Time Lord can regenerate up to 507 times (though 5+0+7=12..) and it has been said that on his episode in the Sarah Jane Adventures. So the numbering doesn't really matter, except for unnecessarily overthinking which is what we're doing here :)


• Sonic Screwdriver - how does it work?

With resonance. In a nutshell, resonance is when you shake something at the right frequency so that it's shaken hardest.
Take radio, for example. When you turn the knob on your radio device, you're changing its parameters so that your favourite station's frequency will resonate in it. You may notice that there's a very precise frequency at which a system resonates - if you turn your radio's knob a little too much you'll lose the station completely. Where I live, there's a radio station on 91.3FM and one on 91.8FM and they don't interfere despite being so close.
But do read more about it.

The Sonic emits waves, sound waves apparently (though I suppose that some of its functionalities would require waves outside the sonic range - subsonic, supersonic), directed to a very specific spot (scientists today are working on speakers that are only heard when pointed at a specific location). It can move things by locking to their frequency/ies and "shaking" them, kind of like a remote controlled pushing hand. It can analyze things by checking which frequencies resonate or at least react in what way in which spots, kind of like an x-ray.

Though I did once see a use of the Sonic on the show that contradicted that theory – but I can't remember what it was.


• Why doesn't the Sonic work on wood?

The Sonic doesn't work on living things. We don't know why, it has just been said on the show. (It could be related to the technology, or maybe an arbitrary range had to be eliminated for technical reasons, quite like how parts of Hubble photos are eliminated for technical reasons. Or maybe the Doctor, being the pacifist that he is, sabotaged his Screwdriver so that it doesn't work on living things. But I digress.)

Wood is made of organic material. It's quite often DEAD organic material, but organic nonetheless. The sonic can't tell that and human cells apart.


• Why did they wed on Wedding of River Song?

It's kind of arbitrary, getting married on the spot when all hell breaks loose. He didn't do it to get close to her, otherwise he could've just said "let me whisper something in your ear", she would, and all would be good.

The Tesselecta crew are "lawful good", they strongly abide by the law. Yes, even when the world could end. They offer the Doctor their help (Wedding of River Song) because they're law abiding people. They withhold information from him even when he's dying despite that information could help him (Let's Kill Hitler) – UNTIL – Amy says she's family. And then they say that if she's family (with Melody) she has privileges.

So they're astonishingly law abiding and one of their laws is that family has access to confidential information. Like.. that the Doctor is inside a tesselecta. He had to wed her to make her family and give her privileges.

Romance is all nice and dandy, but that wedding was for bureaucratical reasons. If it were Kovarian at the centre of the paradox, he'd wed her.

Keep in mind that the crew of the Tesselecta are (or may be) alien, and are from another time, so their logic and reasoning may be different than yours.