The Moon is unique in the solar system in its large relative size compared with the [[Earth]]. The Moon appears from the Earth to be the same size as the [[sun]], in perfect artistic symmetry, unlike any known other planet-moon system. Moreover, unlike most planets in the [[solar system]], [[Earth]] has only one moon, which is designed in two remarkable ways: (1) it rotates and revolves such that only one side is ever visible to the Earth (the possibly only moon with this characteristic)<ref>Some attribute the remarkable orbit and rotation of the Moon as being due to tidal locking.</ref> and (2) its side that faces the Earth is smooth, while the side that remains hidden is jagged. To those on Earth the Moon appears as an artistic disc that goes through phases of varying visibility from Earth. | The Moon is unique in the solar system in its large relative size compared with the [[Earth]]. The Moon appears from the Earth to be the same size as the [[sun]], in perfect artistic symmetry, unlike any known other planet-moon system. Moreover, unlike most planets in the [[solar system]], [[Earth]] has only one moon, which is designed in two remarkable ways: (1) it rotates and revolves such that only one side is ever visible to the Earth (the possibly only moon with this characteristic)<ref>Some attribute the remarkable orbit and rotation of the Moon as being due to tidal locking.</ref> and (2) its side that faces the Earth is smooth, while the side that remains hidden is jagged. To those on Earth the Moon appears as an artistic disc that goes through phases of varying visibility from Earth. |