Night

Night, or nighttime, is the period of darkness when the Sun is below the horizon. Daylight illuminates one side of Earth, leaving the other in darkness. The opposite of nighttime is daytime. Earth's rotation causes the appearance of sunrise and sunset. Moonlight, airglow, starlight, and light pollution dimly illuminate night. The duration of day, night, and twilight varies depending on the time of year and the observer's latitude.