Where & When
The story takes place on, and in orbit around, a planet somewhat strangely named the Sense-Sphere. This is at least in the same galaxy as Earth, but beyond the area of space governed/inhabited by humans at whatever the date may be. Maitland states that that is the 28th century but doesn’t give any more precise figure. If one has to pick a specific year, 2764, eight centuries after the broadcast date, is as good as any. Since it is the first story to be explicitly set in the future, rather than on an alien planet with no apparent connection to Earth, the date had, at the time, no larger context of future history to be placed in – it might as well be plucked from thin air.