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


 * TARDISes are grown, implying that a TARDIS is alive, yet the First Doctor said "it's only a machine".
 * Why is Scooti's corpse floating above the base rather than staying on the planetoid's surface?
 * Only the planet is stopped from being sucked into the black hole. Scooti was sucked into space therefore not immune to the black hole.
 * The device that keeps the planet from being sucked into the black hole does the same for everything that is within its field. That is how the crew was able to get onto the planet in the first place. Therefore, Scooti would be affected by the planet's gravity, not the black hole. So we still have a black plot hole here.


 * Planet could have a lower gravity. The force of her being expelled from the airlock could have exceeded escape velocity.


 * The trapdoor was not 30 feet in diameter as Ida says.
 * Perhaps Ida confused the term diameter with another, such as circumference.


 * Units of measurement could had changed for some reason.


 * Why isn't the black hole sucking in the light around it?
 * Supposedly, it is. The Doctor says at seven minutes, fifty-six seconds into the episode, "Nothing in the universe can escape it. Light, gravity, time, everything just gets pulled inside and crushed," implying that the black hole is, in fact, sucking in light. If you look at the black hole, it appears to be sucking in the light around it constantly. As for the visual effect of the black hole, the people who designed the visuals were probably more concerned with making it visually appealing, not making it look realistic.
 * Right. They're not shooting for scientific accuracy on this fantasy show. In reality, you couldn't see light that failed to escape a black hole being "sucked in", because, well, you only 'see' anything when light reaches you (but you knew that, right?) When it comes down to it, of course, there's actually nothing impossible in the slightest about a planet orbiting a black hole, making the episode's title a bit chuckle-worthy, nor is a stationary orbit around a non-Earth body called "geostationary" . . . and on and on, but that misses the point. Doctor Who is not a realistic show, and regularly pockets its own rules when convenient, to say nothing of the laws of physics. I mean, we are talking about a show where the characters get chased by mummies on Mars . ..
 * I think they're all implying that this planet is within the observed gravitational horizon of the black hole for objects of it's mass. In terms of equivalent to geostationary orbit, this system has no gravitational equivalent to the Moon (an important gravitational force in maintaining the L points). They do use the Scarlett system to establish that they've been observing for a long while, and even objects with larger mass and velocity are passing the planet on their way into the black hole.


 * Whats wrong with a planet orbiting a black hole, if its moving fast enough?
 * Tidal forces. The gravity on one side is significantly stronger than the gravity on the other side, so it tears the planet apart into small debris.
 * Tidal forces that strong wouldn't take affect until you were a lot closer to the black hole.


 * Scooti's body should have exploded after being expelled into space, since there is no pressure or atmosphere (as she states).
 * No. If you depressurise, you won't explode. I know it seems like you will, but instead, you expand. Slowly. Here's exacty what happens when you get sucked out an airlock: The average person can survive with no oxygen for 40 seconds. After that, You go unconcious. About a minute later, you die of suffication. Blood vessels pop, and the blood, given time, will dissolve into its' base components. Some time later, your body would have expanded twice its original size. Flesh is too strong to explode under those circumstances. Eventually, you're freeze-dried. Obviously, this hasen't happened to Scooti yet, but it will. Unless she's sucked into the black hole first.