I think you mean luminous ceiling. If so Its usually having flourescent lights mounted directly to the ceiling of a room and a dropped grid system about 10 to 16 "s below the ordinary ceiling, The dropped grid system has translucent panels in place of the ordinary acoustical tiles usually seen. The flourescent lights shining through the translucent panels make it appear as if the whole ceiling is lit up.

It is luminous

luminous

I think you mean luminous ceiling. If so Its usually having flourescent lights mounted directly to the ceiling of a room and a dropped grid system about 10 to 16 "s below the ordinary ceiling, The dropped grid system has translucent panels in place of the ordinary acoustical tiles usually seen. The flourescent lights shining through the translucent panels make it appear as if the whole ceiling is lit up.

The earth is Non-luminous.