Torvendis can never be fully mapped. The deserts change to forest, the glaciers to rivers of lava, the mountains to ocean troughs and the cities to plains of dust. Trying to chart it seems to make the landscape change even faster, as if Torvendis takes exception to any attempt to unravel its secrets with compass and map. No one on Torvendis ever wakes up to the same world twice, and in a world where even the colour of the sky mutates from hour to hour nothing ever stays the same.
But even the land never changes as much as the patterns of power that have played across Torvendis for aeons, like wildfires flaring and burning out.
The Doctor: I see. This asteroid is sentient.
Auntie: We walk on his back, breathe his air. Eat his food...
Amy: Smell its armpits?
House: (through Auntie and Uncle) And do my will. You are most welcome, travellers.
Amy: Doctor... that voice, that's the asteroid talking?
The Doctor: Yes. So you're like a... sea urchin; hard outer surface- that's the planet we're walking on- big, squashy, oogly thing inside- that's you?