The oldest question in the universe has been transmitting through all of time and space.
It certainly was transmitted through all of space - after all, everybody came to see.
But the part that bothers me is time. From what I gather, the message should have been transmitted in the past, present and future.
Technically, this means that the message must have been transmitting during all the other Doctor Who episodes - not just The time of the Doctor. Since it is the "oldest question in the universe" then clearly it must have been transmitting since way before this episode.
I suppose that the message itself is the "beep" we hear in The time of the Doctor, so my question is: is this beep ever played in any prior Doctor Who episode? If not, is there a canon explanation for its absence?
Figures that such an "overwhelming" transmission through all of time and space would have made at least a few apparitions in previous episodes...