Theory:Doctor Who television discontinuity and plot holes/The Tenth Planet


 * The eyes of the actors playing the Cybermen can be clearly seen through the eye holes.
 * The Cybermen were like us, they are just in their cybernetic early stages.
 * It actually makes sense that the eyes would be the last thing to go. They're more tightly interconnected with the brain than anything else but the spinal cord, and they're less tightly connected with anything other than the brain than almost any other body part.


 * As with other early Doctor Who serials set in "the future", technology and human advancement displayed in this episode, set in 1986, does not coincide with real-world development by that time, even as shown in contemporary stories such as Attack of the Cybermen, and certainly not in later revival series episodes.
 * However, there is repeated precedent involving UNIT, Torchwood Institute, etc. to suggest that the general public was not always aware of the level of technology available on "current-day" earth.
 * Additionally, any perceived discontinuity regarding that would be more appropriately applied to the later episodes.


 * A Mondas Day appears to only be a few Earth seconds.
 * Why shouldn't it be? This could be the result of whatever cosmic force caused it to be pulled out of our solar system all those years ago, and now ultimately returned to it.
 * But the spin speed shown would instantly destroy any Earth-like planet, as the centrifugal force would exceed its gravitational pull.
 * Presumably, the view of Mondas shown was intended to be deliberately speeded up by the Snowcap systems, perhaps to show more clearly the way it was moving.


 * Sometimes the Cybermen start to talk before their mouths open.
 * They're cyborgs, and their voices don't sound like anything conceivably produced by human, or even any kind of animal vocal chords. It's possible the mouths open and close independent of speech, kind of like a Teddy Ruxpin.


 * In episode one when one of the Cybermen is shot his 'ears' flap about.
 * Why shouldn't they? If he still has his human ears and he has been injured, they may well come loose.


 * The script requires the Cybermen to pass for human in their parkas, an effect ruined by the lamps on their heads.
 * Given the weather conditions, they pass well enough.
 * That doesn't explain why no-one apart from the Doctor notices their different shaped heads until they take the parkas off, long after they've entered the base.
 * It does. The weather conditions are bad, and no one is looking too closely at them. If they notice anything, they probably don't think much on it.


 * Barclay says that he designed some of the base, and that he couldn't fit into the ventilation shaft, but it is broad enough to accommodate Geoff Capes.
 * It is possible that an unseen portion of the shaft was narrower than that which is shown.


 * How can Earth and Mondas have identically shaped land masses, as each planet has been separately affected by continental drift for millions of years?
 * Does anyone explicitly state that the continents have moved differently from each other?
 * There is obviously a deeper connection between the two planets rather than just being approximately the same size, given the similarities.


 * It is always seen snowing in Antarctica. In fact, due to its high altitude, the Antarctic air is very dry and precipitation is rare.
 * Although precipitation is relatively rare in Antarctica, it does vary significantly depending upon where in Antarctica you are. It is also not unusual to have white-out conditions, which can resemble snowing.


 * The Cybermen's helmets were held together with Sellotape, which can clearly be seen in this episode.
 * These are a very primitive version of Cybermen.
 * Brits have Sellotape, Americans have Scotch Tape, Cybermen have Cybertape, but they all look and work the same.


 * Obviously, the writers haven't decided yet how many hearts the Doctor has. Polly checks his pulse and finds it normal.
 * It's normal for him, or normal enough so far as Polly knows. She's a secretary, not a doctor, and would not be expected to deduce from his pulse that he might have two hearts.
 * If there is a discontinuity here, but it's in the later episodes that establish that Time Lords have two hearts, not in this episode. Novels, reference books, etc. have offered a few different answers to this:
 * Time Lords have only one heart until they regenerate.
 * "Oldblood" Gallifreyans have only one heart until they regenerate.
 * It's only the Doctor who was born with only one heart until he regenerated, because (a) he was half-human, (b) he was born instead of loomed, (c) he was the reincarnation of a pre-Time Lord Gallifreyan who was attempting the impossible and ended up somewhat scrambled, or (d) some other reason.
 * Possibly the Doctor had two hearts, but one had shut down, either as a defense against a simultaneous double heart attack (which, as later stories explained, causes permanent death rather than regeneration) or because he was far more sickly than he appeared (not too implausible, given that he died and regenerated in this story). Either way, Polly didn't know he was supposed to have a double pulse, so she thought everything was normal.
 * "Oldblood" Gallifreyans have only one heart until they regenerate.
 * It's only the Doctor who was born with only one heart until he regenerated, because (a) he was half-human, (b) he was born instead of loomed, (c) he was the reincarnation of a pre-Time Lord Gallifreyan who was attempting the impossible and ended up somewhat scrambled, or (d) some other reason.
 * Possibly the Doctor had two hearts, but one had shut down, either as a defense against a simultaneous double heart attack (which, as later stories explained, causes permanent death rather than regeneration) or because he was far more sickly than he appeared (not too implausible, given that he died and regenerated in this story). Either way, Polly didn't know he was supposed to have a double pulse, so she thought everything was normal.
 * Possibly the Doctor had two hearts, but one had shut down, either as a defense against a simultaneous double heart attack (which, as later stories explained, causes permanent death rather than regeneration) or because he was far more sickly than he appeared (not too implausible, given that he died and regenerated in this story). Either way, Polly didn't know he was supposed to have a double pulse, so she thought everything was normal.
 * Possibly the Doctor had two hearts, but one had shut down, either as a defense against a simultaneous double heart attack (which, as later stories explained, causes permanent death rather than regeneration) or because he was far more sickly than he appeared (not too implausible, given that he died and regenerated in this story). Either way, Polly didn't know he was supposed to have a double pulse, so she thought everything was normal.


 * When the Cybermen are ambushed outside, one of them has part of his headpiece (one of the "jug handles") come loose.
 * He has just been shot with a powerful energy weapon that would likely cause all kinds of such damage.


 * How did the Doctor know about General Cutler's plan to launch the Z-bomb? Cutler decides to do this in Episode 3, but the Doctor was lying down ill in another room throughout the episode – but he walks into the Tracking Room and says "Your plan is foiled sir!"
 * He obviously overheard the plan while lying there. Also, throughout this story, the Doctor is shown to have some information about what is going on - particularly, the fact that the Cybermen will appear. Presumably he gets this from the same source as his information about the Aztecs, the French Revolution etc - ie. from history files. The Z-Bomb plan could have been mentioned in those same sources. It would be an important element in Earth's history - especially if, without the Doctor, Ben and Polly's intervention, it was detonated.


 * In part 4, Ben refers to Mondas as "Mandos".
 * Simply a variation in inflection, while he's pronouncing an alien word he's never heard before this story.
 * If there's no problem believing that Michael Craze could have got it wrong, why is there any problem believing his character Ben Jackson could have got it wrong?
 * He IS from London. Plus, anyone could get it wrong accidentaly.
 * You might have misheard it.


 * Why do the Cybermen try to use Earth's own Z-bomb to destroy the planet? If they invaded to destroy the Earth and save Mondas, shouldn't they have their own doomsday weapons? What was their plan before they learned of the Z-bomb's existence when Cutler pointed it at Mondas? I don't think the Cybermen would care if Earth's demise was ironic or not.
 * The Cybermen could have known that earth had the Z-bomb and felt no need to waste their own doomsday weapons
 * It still seems very careless considering the Cybermen can't work on disarming and re-purposing the Z-bomb themselves because of the radiation. They require humans to do the work for them and although they take hostages to try and blackmail them into obeying, this by no means guarantees the Cybermen success, especially when they're against the clock in the race to save Mondas from breaking up. Indeed, in the event, Ben and the scientists fight back and the Cybermen don't even do anything to the captive Doctor and Polly in retaliation. Mondas then breaks up shortly afterwards. This seems like a badly thought-out invasion plan on the Cybermen's part, almost requiring the humans - for all intents and purposes, the enemy here - to cooperate with them if they are to succeed. Granted though, this may have been a slapdash invasion that the Cybermen had to launch, once they found themselves in a 'do or die' situation after discovering Earth was killing Mondas in the first place.


 * Why were the Z-bombs created in the first place? When had Earth ever had to destroy another planet before 1986?
 * Tooth and Claw (TV story) shows that we have known about aliens and been preparing to fight them since the 18th century so it is reasonable to assume we would have developed doomsday weapons as we knew that aliens would invade, or maybe we realized we needed to defend ourselves after invasions in episodes like The Invasion (TV story)
 * While Earth has faced many alien threats before 1986, was any one of those invasions really on such a scale that it made the idea that Earth might have to blow up a planet one day sound unexcessive? After all, no one else brought a planet with them before.
 * The universe the Doctor lives in is an alternative universe to the one we live in.