Waning crescent Moon. Image 24 of 27. Optical image of a waning (decreasing in apparent size) crescent Moon 24 days into its 28-day cycle. The lunar p

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Waning crescent Moon. Image 24 of 27. Optical image of a waning (decreasing in apparent size) crescent Moon 24 days into its 28-day cycle. The lunar phases arise as the Moon's orbit of the Earth shows the Earth-facing side moving into and out of the light of the Sun. This Earth-facing side of the Moon is locked in place by the gravitational influence of the Earth. This results in a lunar day that equals the length of the lunar Earth orbit. On a waning Moon the day-night line (terminator) marks the lunar sunset. The Moon is crescent when it is less than half full. Taken in October 2001. A sequence of the monthly cycle of Moon phases is shown on images R340/644-670.

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Size: 3000px × 3000px
Photo credit: © ECKHARD SLAWIK/SCIENCE PHOTO LIBRARY / Alamy / Afripics
License: Licensed
Model Released: No

Keywords: 24, 24-day-, astronomical, astronomy, cosmology, crescent, cycle, cycles, cyclical, days, lunar, mare, maria, moon, optical, period, periodical, periods, phase, phases, planetary, satellite, satellites, science, sea, seas, sunlight, sunlit, waning