The TARDIS stands for `Time and Relative Dimension in Space`. The TARDIS is supposed to change its appearance according to where it is. The device that allows it to do this is called `The Chameleon Circuit` but its malfuctioned. It was never repaired. The copyright to the Police Box belongs to the BBC, having brought the copyright off `New Scotland Yard`, the headquarters of the London (Metropolitan) Police Force.
The ability of the TARDIS to travel in time is due to the power source called `The Eye of Harmony` created by the Gallifreyan scientist `Omega`. How it works isn`t clear but it is understood that... Omega would detonate a star using a stellar manipulator called `The Hand of Omega`, bring it back to Gallifrey and then use the immense forces of the crushed star to power the time travel experiments. Omega was betrayed by Rassilon, the founder of the Time Lord Society. Omega`s ship was sucked into the explosion and believed to be dead. He had in fact been sucked into an anti-matter universe. (This is mentioned in the The Three Doctors adventure.) The follow-up episode The Arc of Infinity
Inside the Tardis
The Tardis is famous for being bigger on the inside compared to what it looks like on the outside. The inside of the Tardis is accessible from the outside through the Police Box front door. When the Doctor regenerates, the inside of the Tardis also regenerates. The controls for the Tardis stay in the same place but the environment and look and feel changes. The picture below is what the Tardis control room looked like when Matt Smith was the Doctor.
Tardis Power Source
The ship is supposedly infinite in size but that`ll make it as big as the universe. In Journey To the Centre of the Tardis, we see the power source at the heart of the Tardis, a massive star. The Tardis is able to hold the energy inside and shrink it so that the ship can appear as a police box.
Dear RH, The TARDIS is no mere machine that requires parts replacement every 10,000 parsecs; it's a type 40 Time and Relative Dimension in Space capsule--as such, it is fully self contained and sufficient. It requires no spare parts from Gallifrey anymore than it needs interchangeable parts if it wants to change its external appearance via the Chameleon Circuit. The Doctor is able to change the inside of the TARDIS or change the "desktop theme" as stated by the 5th Doctor in Time Crash, when he met his future self, the 10th Doctor. Try YouTubing..."Time Crash". In the episode, Invasion of Time, the Chancellor Borusa, the Doctor's old academy professor, tells the 4th Doctor to stabilize the TARDIS's dimensional infrastructure. This implies that the Doctor has complete control over the structural configuration of his time capsule. The Doctor's planet, Gallifrey, is not utterly destroyed. The connection between the TARDIS's 'Eye of Harmony' and the black hole which powers the ability to time travel is not severed. The evidence of this is in the fact that the Doctor can still time travel. I believe that the planet Gallifrey is still intact, although lifeless, because of the still operational Quantum Barrier. Again, look up Invasion of Time to know both the Quantum and Transduction Barriers of Gallifrey. As for your personal taste in the TARDIS interior, I will agree with you in that it would not be my style of decorum. I rather prefer the 5th Doctors style of decoration.
i love it
i believe that the new tardis is absalutely stupid the inside is completely garbage and that if his planet was destroyed how did he get all the equipment to change the inside of the tardis hmm