a person or thing that retracts. Anatomy. a muscle that retracts an organ or protruded part. Surgery. an instrument or appliance for drawing back an impeding part, as the edge of an incision. a mechanism, device, or the like that regulates retraction: to adjust the retractor on a seat belt.
The Moon orbits Earth in the prograde direction and completes one revolution relative to the stars in approximately 27.323 days (a sidereal month). Earth and the Moon orbit about their barycentre (common center of mass), which lies about 4,600 km (2,900 mi) from Earth's center (about 34 of the radius of Earth).
Not to be confused with Lunar orbit (the orbit of an object around the Moon). The Moon orbits Earth in the prograde direction and completes one revolution in approximately 27.322 days (a sidereal month).Earth and the Moon orbit about their barycentre (common center of mass), which lies about 4600 km from Earth's center (about three quarters of the radius of Earth).On average, the Moon is at a distance of about 385000 km from Earth's center, which corresponds to about 60 Earth radii.With a mean orbital velocity of 1.023 km/s, the Moon moves relative to the stars each hour by an amount roughly equal to its angular diameter, or by about 0.5Â°.n average, the Moon is at a distance of about 385000 km from Earth's center, which corresponds to about 60 Earth radii. With a mean orbital velocity of 1.023 km/s, the Moon moves relative to the stars each hour by an amount roughly equal to its angular diameter, or by about 0.5Â°.