Question: In which season and episode is Gallifrey destroyed, or is it just a shocking new plot development for the new series?
Question: If the Doctor gets a TARDIS, does that mean other Timelords get a TARDIS as well?
Answer: TARDISes are generally available for properly authorised use on Gallifrey; they're not usually assigned to a particular Timelord on a long-term basis. The Doctor stole his when he left his homeworld.
Question: What does the Doctor mean at the end of the episode about changing the colours of the ships or spaceships from green to white? Is this a reference to an earlier episode or something else?
Chosen answer: In the original legend of the Minotaur, Theseus' ship was supposed to approach Athens with white sails if he had slain the creature, or black sails if he had been killed. Although he killed the Minotaur, he forgot to change the sails to white and his father, King Aegeus, killed himself in despair. Two stories earlier ("The Creature from the Pit"), the Doctor claimed to have been involved in the original legend and said he had forgotten to remind Theseus about the sails.
Question: What caused the first Doctor to regenerate? Was it old age?
Chosen answer: No, it was the result of the Cybermen's draining Earth of energy to their world, that also affected the Doctor, draining his energy as well, causing him to regenerate.
Also In the episode it's said that his body was wearing thin.
Question: I wanted to know what was the name of the episode where these cancerous creatures suck the bones out of you and turn you into a pile of mush - it was one of the first episodes I think.
Answer: Your right it is, "Island of Terror."
Answer: I don't think this was a Doctor Who story. It sounds more like the 1966 film "Island of Terror" (although it did star Peter Cushing who played Dr Who in two Dalek movies around the same time).
Answer: It was never destroyed on-screen; it was intact at the end of the TV movie, and destroyed by the start of the 2005 series. It was destroyed in the novel "The Ancestor Cell," but in a completely different manner to what happened in the series.
DaveJB