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Lunar day
Time for Moon to complete one rotation on its axis / From Wikipedia, the free encyclopedia
See also: Synodic day
For the tidal lunar day of about 24 hours and 50 minutes, see Tide.
A lunar day is the time it takes for Earth's Moon to complete on its axis one synodic rotation, meaning with respect to the Sun. Informally, a lunar day and a lunar night is each approx. 14 Earth days. The formal lunar day is therefore the time of a full lunar day-night cycle. Due to tidal locking, this equals the time that the Moon takes to complete one synodic orbit around Earth, a synodic lunar month, returning to the same lunar phase. The synodic period is about 29+1⁄2 Earth days, which is about 2.2 days longer than its sidereal period.
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