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Twilight is the time between darkness and sunrise in the morning, and sunset and complete darkness in the evening, when there is light outside, but the Sun is below the horizon. There are 3 types of twilight: civil, nautical, and astronomical. Dubai skyline in twilight.
Twilight is produced by sunlight scattering in the upper atmosphere, illuminating the lower atmosphere so that the surface of the Earth is neither completely lit nor completely dark. The word twilight is also used to denote the periods of time when this illumination occurs. The further the Sun is below the horizon, the dimmer the twilight (other things such as atmospheric conditions being equal).