'''Twilight''' is the time between [[dawn]] and sunrise, and between [[sunset]] and [[dusk]]. Sunlight scattered in the upper [[atmosphere]] [[illuminates]] the lower atmosphere, and the [[surface]] of the [[Earth]] is neither completely lit nor completely dark. The [[sun]] itself is not actually visible because it is below the [[horizon]]. Owing to the unusual [[quality]] of the ambient light at this time, twilight has long been popular with photographers and painters, who refer to it as the "blue hour", after the French [[expression]] l'heure bleue. Twilight is [[technically]] defined as the period before sunrise and after sunset during which there is [[natural]] [[light]] provided by the upper [[atmosphere]], which receives direct sunlight and scatters part of it towards the [[Earth]]'s [[surface]]. | '''Twilight''' is the time between [[dawn]] and sunrise, and between [[sunset]] and [[dusk]]. Sunlight scattered in the upper [[atmosphere]] [[illuminates]] the lower atmosphere, and the [[surface]] of the [[Earth]] is neither completely lit nor completely dark. The [[sun]] itself is not actually visible because it is below the [[horizon]]. Owing to the unusual [[quality]] of the ambient light at this time, twilight has long been popular with photographers and painters, who refer to it as the "blue hour", after the French [[expression]] l'heure bleue. Twilight is [[technically]] defined as the period before sunrise and after sunset during which there is [[natural]] [[light]] provided by the upper [[atmosphere]], which receives direct sunlight and scatters part of it towards the [[Earth]]'s [[surface]]. |