Red or green lights, maybe (6)
I believe the answer is:
aurora
(Other definitions for aurora that I've seen before include "Polar light show" , "Northern/southern lights" , "Display of lights in the night sky" , "skylights?" , "Orange" .)
I believe the answer is:
aurora
(Other definitions for aurora that I've seen before include "Polar light show" , "Northern/southern lights" , "Display of lights in the night sky" , "skylights?" , "Orange" .)