Sense Sphere

The Sense Sphere was the home planet of the Sensorites.

Geography
The Tenth Doctor confirmed that the Sense Sphere was located in the same star system as the Ood Sphere. (DW: Planet of the Ood) It had two suns, which meant the planet never had natural night-time. The planet was also riddled with caves, which is where the Zilgans lived. (DWA: The Monsters from Earth) It was also rich in molybdenum. (DW: The Sensorites)

History
During the 28th century, the Sense Sphere was visited by two separate Earth expeditions. The humans wanted to mine the molybdenum. The First Doctor ensured that the Sense Sphere would not end up exploited by humans as the native Sensorites would rather they left them alone. (DW: The Sensorites)