Rose Tyler: Really, though, Doctor... Tell me. Who are you?

Doctor: Do you know like we were saying? About the Earth revolving? It's like when you're a kid. The first time they tell you the world's turning and you can't believe it cos it looks like everything's standing still... I can feel it. (takes her hand) The turn of the Earth. The ground beneath our feet is spinning at 1,000 miles an hour. The entire planet is hurtling round the sun at 67,000 miles an hour. I can feel it, we're falling through Space, you and me. Clinging to the skin of this tiny little world, and if we let go... (lets go of her hand) That's who I am. Now forget me, Rose Tyler. Go home.