Young Brunette Girl Undresses Her Black Bikini On The Beach In The Sand During Sunset

Sunset or sundown is the daily disappearance of the Sun below the horizon as a result of Earth's rotation.
The time of sunset is defined in astronomy as the moment the trailing edge of the Sun's disk disappears below the horizon in the west. The ray path of light from the setting Sun is highly distorted near the horizon because of atmospheric refraction, making the apparent astronomical sunset occur when the Sun’s disk is already about one diameter below the horizon. Sunset is distinct from dusk, which is the moment at which darkness falls, which occurs when the Sun is approximately eighteen degrees below the horizon. The period between the astronomical sunset and dusk is called twilight.
Locations north of the Arctic Circle and south of the Antarctic Circle experience no sunset or sunrise at least one day of the year, when the polar day or the polar night persist continuously for 24 hours.